VandenBroeck and Keller, Equation (20)

Percentage Accurate: 6.7% → 99.1%
Time: 6.8s
Alternatives: 16
Speedup: 4.8×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{\pi}{4} \cdot f\\ t_1 := e^{t\_0}\\ t_2 := e^{-t\_0}\\ -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right) \end{array} \end{array} \]
(FPCore (f)
 :precision binary64
 (let* ((t_0 (* (/ PI 4.0) f)) (t_1 (exp t_0)) (t_2 (exp (- t_0))))
   (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ t_1 t_2) (- t_1 t_2)))))))
double code(double f) {
	double t_0 = (((double) M_PI) / 4.0) * f;
	double t_1 = exp(t_0);
	double t_2 = exp(-t_0);
	return -((1.0 / (((double) M_PI) / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
}
public static double code(double f) {
	double t_0 = (Math.PI / 4.0) * f;
	double t_1 = Math.exp(t_0);
	double t_2 = Math.exp(-t_0);
	return -((1.0 / (Math.PI / 4.0)) * Math.log(((t_1 + t_2) / (t_1 - t_2))));
}
def code(f):
	t_0 = (math.pi / 4.0) * f
	t_1 = math.exp(t_0)
	t_2 = math.exp(-t_0)
	return -((1.0 / (math.pi / 4.0)) * math.log(((t_1 + t_2) / (t_1 - t_2))))
function code(f)
	t_0 = Float64(Float64(pi / 4.0) * f)
	t_1 = exp(t_0)
	t_2 = exp(Float64(-t_0))
	return Float64(-Float64(Float64(1.0 / Float64(pi / 4.0)) * log(Float64(Float64(t_1 + t_2) / Float64(t_1 - t_2)))))
end
function tmp = code(f)
	t_0 = (pi / 4.0) * f;
	t_1 = exp(t_0);
	t_2 = exp(-t_0);
	tmp = -((1.0 / (pi / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
end
code[f_] := Block[{t$95$0 = N[(N[(Pi / 4.0), $MachinePrecision] * f), $MachinePrecision]}, Block[{t$95$1 = N[Exp[t$95$0], $MachinePrecision]}, Block[{t$95$2 = N[Exp[(-t$95$0)], $MachinePrecision]}, (-N[(N[(1.0 / N[(Pi / 4.0), $MachinePrecision]), $MachinePrecision] * N[Log[N[(N[(t$95$1 + t$95$2), $MachinePrecision] / N[(t$95$1 - t$95$2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision])]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{\pi}{4} \cdot f\\
t_1 := e^{t\_0}\\
t_2 := e^{-t\_0}\\
-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right)
\end{array}
\end{array}

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 16 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 6.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{\pi}{4} \cdot f\\ t_1 := e^{t\_0}\\ t_2 := e^{-t\_0}\\ -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right) \end{array} \end{array} \]
(FPCore (f)
 :precision binary64
 (let* ((t_0 (* (/ PI 4.0) f)) (t_1 (exp t_0)) (t_2 (exp (- t_0))))
   (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ t_1 t_2) (- t_1 t_2)))))))
double code(double f) {
	double t_0 = (((double) M_PI) / 4.0) * f;
	double t_1 = exp(t_0);
	double t_2 = exp(-t_0);
	return -((1.0 / (((double) M_PI) / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
}
public static double code(double f) {
	double t_0 = (Math.PI / 4.0) * f;
	double t_1 = Math.exp(t_0);
	double t_2 = Math.exp(-t_0);
	return -((1.0 / (Math.PI / 4.0)) * Math.log(((t_1 + t_2) / (t_1 - t_2))));
}
def code(f):
	t_0 = (math.pi / 4.0) * f
	t_1 = math.exp(t_0)
	t_2 = math.exp(-t_0)
	return -((1.0 / (math.pi / 4.0)) * math.log(((t_1 + t_2) / (t_1 - t_2))))
function code(f)
	t_0 = Float64(Float64(pi / 4.0) * f)
	t_1 = exp(t_0)
	t_2 = exp(Float64(-t_0))
	return Float64(-Float64(Float64(1.0 / Float64(pi / 4.0)) * log(Float64(Float64(t_1 + t_2) / Float64(t_1 - t_2)))))
end
function tmp = code(f)
	t_0 = (pi / 4.0) * f;
	t_1 = exp(t_0);
	t_2 = exp(-t_0);
	tmp = -((1.0 / (pi / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
end
code[f_] := Block[{t$95$0 = N[(N[(Pi / 4.0), $MachinePrecision] * f), $MachinePrecision]}, Block[{t$95$1 = N[Exp[t$95$0], $MachinePrecision]}, Block[{t$95$2 = N[Exp[(-t$95$0)], $MachinePrecision]}, (-N[(N[(1.0 / N[(Pi / 4.0), $MachinePrecision]), $MachinePrecision] * N[Log[N[(N[(t$95$1 + t$95$2), $MachinePrecision] / N[(t$95$1 - t$95$2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision])]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{\pi}{4} \cdot f\\
t_1 := e^{t\_0}\\
t_2 := e^{-t\_0}\\
-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right)
\end{array}
\end{array}

Alternative 1: 99.1% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := e^{\frac{\pi}{4} \cdot \left(-f\right)}\\ t_1 := \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, 0.0026041666666666665, 0.03125 \cdot \left(\pi \cdot \pi\right)\right), f, 0.25 \cdot \pi\right), f, 1\right)\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + t\_1}{t\_1 - t\_0}\right)\right)\\ \end{array} \end{array} \]
(FPCore (f)
 :precision binary64
 (let* ((t_0 (exp (* (/ PI 4.0) (- f))))
        (t_1
         (fma
          (fma
           (fma
            (* (* (* PI PI) PI) f)
            0.0026041666666666665
            (* 0.03125 (* PI PI)))
           f
           (* 0.25 PI))
          f
          1.0)))
   (if (<= f 23.0)
     (*
      (-
       (/ (log (cosh (* (* f PI) -0.25))) PI)
       (/ (log (sinh (* (* f PI) 0.25))) PI))
      -4.0)
     (* (/ 4.0 PI) (- (log (/ (+ t_0 t_1) (- t_1 t_0))))))))
double code(double f) {
	double t_0 = exp(((((double) M_PI) / 4.0) * -f));
	double t_1 = fma(fma(fma((((((double) M_PI) * ((double) M_PI)) * ((double) M_PI)) * f), 0.0026041666666666665, (0.03125 * (((double) M_PI) * ((double) M_PI)))), f, (0.25 * ((double) M_PI))), f, 1.0);
	double tmp;
	if (f <= 23.0) {
		tmp = ((log(cosh(((f * ((double) M_PI)) * -0.25))) / ((double) M_PI)) - (log(sinh(((f * ((double) M_PI)) * 0.25))) / ((double) M_PI))) * -4.0;
	} else {
		tmp = (4.0 / ((double) M_PI)) * -log(((t_0 + t_1) / (t_1 - t_0)));
	}
	return tmp;
}
function code(f)
	t_0 = exp(Float64(Float64(pi / 4.0) * Float64(-f)))
	t_1 = fma(fma(fma(Float64(Float64(Float64(pi * pi) * pi) * f), 0.0026041666666666665, Float64(0.03125 * Float64(pi * pi))), f, Float64(0.25 * pi)), f, 1.0)
	tmp = 0.0
	if (f <= 23.0)
		tmp = Float64(Float64(Float64(log(cosh(Float64(Float64(f * pi) * -0.25))) / pi) - Float64(log(sinh(Float64(Float64(f * pi) * 0.25))) / pi)) * -4.0);
	else
		tmp = Float64(Float64(4.0 / pi) * Float64(-log(Float64(Float64(t_0 + t_1) / Float64(t_1 - t_0)))));
	end
	return tmp
end
code[f_] := Block[{t$95$0 = N[Exp[N[(N[(Pi / 4.0), $MachinePrecision] * (-f)), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(N[(N[(N[(Pi * Pi), $MachinePrecision] * Pi), $MachinePrecision] * f), $MachinePrecision] * 0.0026041666666666665 + N[(0.03125 * N[(Pi * Pi), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * f + N[(0.25 * Pi), $MachinePrecision]), $MachinePrecision] * f + 1.0), $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], N[(N[(4.0 / Pi), $MachinePrecision] * (-N[Log[N[(N[(t$95$0 + t$95$1), $MachinePrecision] / N[(t$95$1 - t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{4} \cdot \left(-f\right)}\\
t_1 := \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, 0.0026041666666666665, 0.03125 \cdot \left(\pi \cdot \pi\right)\right), f, 0.25 \cdot \pi\right), f, 1\right)\\
\mathbf{if}\;f \leq 23:\\
\;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\

\mathbf{else}:\\
\;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + t\_1}{t\_1 - t\_0}\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if f < 23

    1. Initial program 6.7%

      \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
    2. Taylor expanded in f around inf

      \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
    4. Applied rewrites99.4%

      \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
    5. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      3. lift-cosh.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      4. lift-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      5. lift-PI.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      6. lift-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      7. lift-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      8. lift-sinh.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      9. lift-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      10. lift-PI.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      11. lift-*.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
      12. lower-log.f64N/A

        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
    6. Applied rewrites99.4%

      \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
    7. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
      2. lift-/.f64N/A

        \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
    8. Applied rewrites99.4%

      \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

    if 23 < f

    1. Initial program 3.0%

      \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
    2. Taylor expanded in f around 0

      \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
    3. Step-by-step derivation
      1. Applied rewrites1.7%

        \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
      2. Taylor expanded in f around 0

        \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
      3. Step-by-step derivation
        1. Applied rewrites86.1%

          \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
        2. Step-by-step derivation
          1. lift-neg.f64N/A

            \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} \]
          2. lift-*.f64N/A

            \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)}\right) \]
          3. distribute-rgt-neg-inN/A

            \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
          4. lower-*.f64N/A

            \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
        3. Applied rewrites86.1%

          \[\leadsto \color{blue}{\frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right)} \]
        4. Taylor expanded in f around 0

          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \color{blue}{\left(1 + f \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right)\right)\right)}}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
        5. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \left(f \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right)\right) + \color{blue}{1}\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
          2. *-commutativeN/A

            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \left(\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right)\right) \cdot f + 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
          3. lower-fma.f64N/A

            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right), \color{blue}{f}, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
        6. Applied rewrites3.6%

          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, 0.0026041666666666665, 0.03125 \cdot \left(\pi \cdot \pi\right)\right), f, 0.25 \cdot \pi\right), f, 1\right)}}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
        7. Taylor expanded in f around 0

          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, \frac{1}{384}, \frac{1}{32} \cdot \left(\pi \cdot \pi\right)\right), f, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\color{blue}{\left(1 + f \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right)\right)\right)} - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
        8. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, \frac{1}{384}, \frac{1}{32} \cdot \left(\pi \cdot \pi\right)\right), f, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\left(f \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right)\right) + \color{blue}{1}\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
          2. *-commutativeN/A

            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, \frac{1}{384}, \frac{1}{32} \cdot \left(\pi \cdot \pi\right)\right), f, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\left(\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right)\right) \cdot f + 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
          3. lower-fma.f64N/A

            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, \frac{1}{384}, \frac{1}{32} \cdot \left(\pi \cdot \pi\right)\right), f, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) + f \cdot \left(\frac{1}{384} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{3}\right) + \frac{1}{32} \cdot {\mathsf{PI}\left(\right)}^{2}\right), \color{blue}{f}, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
        9. Applied rewrites86.1%

          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, 0.0026041666666666665, 0.03125 \cdot \left(\pi \cdot \pi\right)\right), f, 0.25 \cdot \pi\right), f, 1\right)}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\pi \cdot \pi\right) \cdot \pi\right) \cdot f, 0.0026041666666666665, 0.03125 \cdot \left(\pi \cdot \pi\right)\right), f, 0.25 \cdot \pi\right), f, 1\right)} - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
      4. Recombined 2 regimes into one program.
      5. Add Preprocessing

      Alternative 2: 99.1% accurate, 0.9× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_0 := e^{\frac{\pi}{4} \cdot \left(-f\right)}\\ t_1 := \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + t\_1}{t\_1 - t\_0}\right)\right)\\ \end{array} \end{array} \]
      (FPCore (f)
       :precision binary64
       (let* ((t_0 (exp (* (/ PI 4.0) (- f))))
              (t_1 (fma (fma (* (* PI PI) f) 0.03125 (* 0.25 PI)) f 1.0)))
         (if (<= f 23.0)
           (*
            (-
             (/ (log (cosh (* (* f PI) -0.25))) PI)
             (/ (log (sinh (* (* f PI) 0.25))) PI))
            -4.0)
           (* (/ 4.0 PI) (- (log (/ (+ t_0 t_1) (- t_1 t_0))))))))
      double code(double f) {
      	double t_0 = exp(((((double) M_PI) / 4.0) * -f));
      	double t_1 = fma(fma(((((double) M_PI) * ((double) M_PI)) * f), 0.03125, (0.25 * ((double) M_PI))), f, 1.0);
      	double tmp;
      	if (f <= 23.0) {
      		tmp = ((log(cosh(((f * ((double) M_PI)) * -0.25))) / ((double) M_PI)) - (log(sinh(((f * ((double) M_PI)) * 0.25))) / ((double) M_PI))) * -4.0;
      	} else {
      		tmp = (4.0 / ((double) M_PI)) * -log(((t_0 + t_1) / (t_1 - t_0)));
      	}
      	return tmp;
      }
      
      function code(f)
      	t_0 = exp(Float64(Float64(pi / 4.0) * Float64(-f)))
      	t_1 = fma(fma(Float64(Float64(pi * pi) * f), 0.03125, Float64(0.25 * pi)), f, 1.0)
      	tmp = 0.0
      	if (f <= 23.0)
      		tmp = Float64(Float64(Float64(log(cosh(Float64(Float64(f * pi) * -0.25))) / pi) - Float64(log(sinh(Float64(Float64(f * pi) * 0.25))) / pi)) * -4.0);
      	else
      		tmp = Float64(Float64(4.0 / pi) * Float64(-log(Float64(Float64(t_0 + t_1) / Float64(t_1 - t_0)))));
      	end
      	return tmp
      end
      
      code[f_] := Block[{t$95$0 = N[Exp[N[(N[(Pi / 4.0), $MachinePrecision] * (-f)), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(N[(Pi * Pi), $MachinePrecision] * f), $MachinePrecision] * 0.03125 + N[(0.25 * Pi), $MachinePrecision]), $MachinePrecision] * f + 1.0), $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], N[(N[(4.0 / Pi), $MachinePrecision] * (-N[Log[N[(N[(t$95$0 + t$95$1), $MachinePrecision] / N[(t$95$1 - t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])), $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_0 := e^{\frac{\pi}{4} \cdot \left(-f\right)}\\
      t_1 := \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)\\
      \mathbf{if}\;f \leq 23:\\
      \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\
      
      \mathbf{else}:\\
      \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + t\_1}{t\_1 - t\_0}\right)\right)\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if f < 23

        1. Initial program 6.7%

          \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
        2. Taylor expanded in f around inf

          \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
        3. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
          2. lower-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
        4. Applied rewrites99.4%

          \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
        5. Step-by-step derivation
          1. lift-/.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          2. lift-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          3. lift-cosh.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          4. lift-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          5. lift-PI.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          6. lift-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          7. lift-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          8. lift-sinh.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          9. lift-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          10. lift-PI.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          11. lift-*.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
          12. lower-log.f64N/A

            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
        6. Applied rewrites99.4%

          \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
        7. Step-by-step derivation
          1. lift-PI.f64N/A

            \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
          2. lift-/.f64N/A

            \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
        8. Applied rewrites99.4%

          \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

        if 23 < f

        1. Initial program 3.0%

          \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
        2. Taylor expanded in f around 0

          \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
        3. Step-by-step derivation
          1. Applied rewrites1.7%

            \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
          2. Taylor expanded in f around 0

            \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
          3. Step-by-step derivation
            1. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Step-by-step derivation
              1. lift-neg.f64N/A

                \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} \]
              2. lift-*.f64N/A

                \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)}\right) \]
              3. distribute-rgt-neg-inN/A

                \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
              4. lower-*.f64N/A

                \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
            3. Applied rewrites86.1%

              \[\leadsto \color{blue}{\frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right)} \]
            4. Taylor expanded in f around 0

              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \color{blue}{\left(1 + f \cdot \left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right)\right)}}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
            5. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \left(f \cdot \left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              2. *-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \left(\left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right) \cdot f + 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              3. lower-fma.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right), \color{blue}{f}, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              4. *-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) \cdot \frac{1}{32} + \frac{1}{4} \cdot \mathsf{PI}\left(\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              5. lower-fma.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(f \cdot {\mathsf{PI}\left(\right)}^{2}, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              6. *-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left({\mathsf{PI}\left(\right)}^{2} \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              7. lower-*.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left({\mathsf{PI}\left(\right)}^{2} \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              8. unpow2N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              9. lower-*.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              10. lift-PI.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \mathsf{PI}\left(\right)\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              11. lift-PI.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              12. lower-*.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              13. lift-PI.f643.6

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
            6. Applied rewrites3.6%

              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)}}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
            7. Taylor expanded in f around 0

              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\color{blue}{\left(1 + f \cdot \left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right)\right)} - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
            8. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\left(f \cdot \left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              2. *-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\left(\left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right) \cdot f + 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              3. lower-fma.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\frac{1}{32} \cdot \left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) + \frac{1}{4} \cdot \mathsf{PI}\left(\right), \color{blue}{f}, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              4. *-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\left(f \cdot {\mathsf{PI}\left(\right)}^{2}\right) \cdot \frac{1}{32} + \frac{1}{4} \cdot \mathsf{PI}\left(\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              5. lower-fma.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(f \cdot {\mathsf{PI}\left(\right)}^{2}, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              6. *-commutativeN/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left({\mathsf{PI}\left(\right)}^{2} \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              7. lower-*.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left({\mathsf{PI}\left(\right)}^{2} \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              8. unpow2N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              9. lower-*.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              10. lift-PI.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \mathsf{PI}\left(\right)\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              11. lift-PI.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              12. lower-*.f64N/A

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, \frac{1}{32}, \frac{1}{4} \cdot \mathsf{PI}\left(\right)\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
              13. lift-PI.f6486.1

                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right) - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
            9. Applied rewrites86.1%

              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + \mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\left(\pi \cdot \pi\right) \cdot f, 0.03125, 0.25 \cdot \pi\right), f, 1\right)} - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
          4. Recombined 2 regimes into one program.
          5. Add Preprocessing

          Alternative 3: 99.1% accurate, 1.0× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(f \cdot \pi\right) \cdot 0.25\\ t_1 := \mathsf{fma}\left(f \cdot \pi, 0.25, 1\right)\\ t_2 := e^{-t\_0}\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh t\_0}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;\log \left({\left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right)}^{\left(-\frac{1}{\pi} \cdot 4\right)}\right)\\ \end{array} \end{array} \]
          (FPCore (f)
           :precision binary64
           (let* ((t_0 (* (* f PI) 0.25))
                  (t_1 (fma (* f PI) 0.25 1.0))
                  (t_2 (exp (- t_0))))
             (if (<= f 23.0)
               (*
                (- (/ (log (cosh (* (* f PI) -0.25))) PI) (/ (log (sinh t_0)) PI))
                -4.0)
               (log (pow (/ (+ t_1 t_2) (- t_1 t_2)) (- (* (/ 1.0 PI) 4.0)))))))
          double code(double f) {
          	double t_0 = (f * ((double) M_PI)) * 0.25;
          	double t_1 = fma((f * ((double) M_PI)), 0.25, 1.0);
          	double t_2 = exp(-t_0);
          	double tmp;
          	if (f <= 23.0) {
          		tmp = ((log(cosh(((f * ((double) M_PI)) * -0.25))) / ((double) M_PI)) - (log(sinh(t_0)) / ((double) M_PI))) * -4.0;
          	} else {
          		tmp = log(pow(((t_1 + t_2) / (t_1 - t_2)), -((1.0 / ((double) M_PI)) * 4.0)));
          	}
          	return tmp;
          }
          
          function code(f)
          	t_0 = Float64(Float64(f * pi) * 0.25)
          	t_1 = fma(Float64(f * pi), 0.25, 1.0)
          	t_2 = exp(Float64(-t_0))
          	tmp = 0.0
          	if (f <= 23.0)
          		tmp = Float64(Float64(Float64(log(cosh(Float64(Float64(f * pi) * -0.25))) / pi) - Float64(log(sinh(t_0)) / pi)) * -4.0);
          	else
          		tmp = log((Float64(Float64(t_1 + t_2) / Float64(t_1 - t_2)) ^ Float64(-Float64(Float64(1.0 / pi) * 4.0))));
          	end
          	return tmp
          end
          
          code[f_] := Block[{t$95$0 = N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]}, Block[{t$95$1 = N[(N[(f * Pi), $MachinePrecision] * 0.25 + 1.0), $MachinePrecision]}, Block[{t$95$2 = N[Exp[(-t$95$0)], $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[t$95$0], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], N[Log[N[Power[N[(N[(t$95$1 + t$95$2), $MachinePrecision] / N[(t$95$1 - t$95$2), $MachinePrecision]), $MachinePrecision], (-N[(N[(1.0 / Pi), $MachinePrecision] * 4.0), $MachinePrecision])], $MachinePrecision]], $MachinePrecision]]]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \left(f \cdot \pi\right) \cdot 0.25\\
          t_1 := \mathsf{fma}\left(f \cdot \pi, 0.25, 1\right)\\
          t_2 := e^{-t\_0}\\
          \mathbf{if}\;f \leq 23:\\
          \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh t\_0}{\pi}\right) \cdot -4\\
          
          \mathbf{else}:\\
          \;\;\;\;\log \left({\left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right)}^{\left(-\frac{1}{\pi} \cdot 4\right)}\right)\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if f < 23

            1. Initial program 6.7%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around inf

              \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
            3. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
              2. lower-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
            4. Applied rewrites99.4%

              \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
            5. Step-by-step derivation
              1. lift-/.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              2. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              3. lift-cosh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              4. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              5. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              6. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              7. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              8. lift-sinh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              9. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              10. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              11. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              12. lower-log.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
            6. Applied rewrites99.4%

              \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
            7. Step-by-step derivation
              1. lift-PI.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
              2. lift-/.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
            8. Applied rewrites99.4%

              \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

            if 23 < f

            1. Initial program 3.0%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\left(1 + \frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            3. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lower-fma.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(f \cdot \mathsf{PI}\left(\right), \color{blue}{\frac{1}{4}}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              5. lower-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              6. lift-PI.f641.7

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            4. Applied rewrites1.7%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            5. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\left(1 + \frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            6. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\left(\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lower-fma.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(f \cdot \mathsf{PI}\left(\right), \color{blue}{\frac{1}{4}}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              5. lower-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              6. lift-PI.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            7. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            8. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\color{blue}{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            9. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{1}{4}}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \color{blue}{0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            10. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\color{blue}{\left(f \cdot \pi\right) \cdot 0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            11. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\color{blue}{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right) \]
            12. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{1}{4}}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \color{blue}{0.25}}}\right) \]
            13. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\color{blue}{\left(f \cdot \pi\right) \cdot 0.25}}}\right) \]
            14. Step-by-step derivation
              1. lift-neg.f64N/A

                \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right)\right)} \]
              2. lift-*.f64N/A

                \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right)}\right) \]
            15. Applied rewrites86.1%

              \[\leadsto \color{blue}{\log \left({\left(\frac{\mathsf{fma}\left(f \cdot \pi, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(f \cdot \pi, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right)}^{\left(-\frac{1}{\pi} \cdot 4\right)}\right)} \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 4: 99.1% accurate, 1.2× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(f \cdot \pi\right) \cdot -0.25\\ t_1 := \mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)\\ t_2 := e^{t\_0}\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh t\_0}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right)\\ \end{array} \end{array} \]
          (FPCore (f)
           :precision binary64
           (let* ((t_0 (* (* f PI) -0.25)) (t_1 (fma (* PI f) 0.25 1.0)) (t_2 (exp t_0)))
             (if (<= f 23.0)
               (* (- (/ (log (cosh t_0)) PI) (/ (log (sinh (* (* f PI) 0.25))) PI)) -4.0)
               (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ t_1 t_2) (- t_1 t_2))))))))
          double code(double f) {
          	double t_0 = (f * ((double) M_PI)) * -0.25;
          	double t_1 = fma((((double) M_PI) * f), 0.25, 1.0);
          	double t_2 = exp(t_0);
          	double tmp;
          	if (f <= 23.0) {
          		tmp = ((log(cosh(t_0)) / ((double) M_PI)) - (log(sinh(((f * ((double) M_PI)) * 0.25))) / ((double) M_PI))) * -4.0;
          	} else {
          		tmp = -((1.0 / (((double) M_PI) / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
          	}
          	return tmp;
          }
          
          function code(f)
          	t_0 = Float64(Float64(f * pi) * -0.25)
          	t_1 = fma(Float64(pi * f), 0.25, 1.0)
          	t_2 = exp(t_0)
          	tmp = 0.0
          	if (f <= 23.0)
          		tmp = Float64(Float64(Float64(log(cosh(t_0)) / pi) - Float64(log(sinh(Float64(Float64(f * pi) * 0.25))) / pi)) * -4.0);
          	else
          		tmp = Float64(-Float64(Float64(1.0 / Float64(pi / 4.0)) * log(Float64(Float64(t_1 + t_2) / Float64(t_1 - t_2)))));
          	end
          	return tmp
          end
          
          code[f_] := Block[{t$95$0 = N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]}, Block[{t$95$1 = N[(N[(Pi * f), $MachinePrecision] * 0.25 + 1.0), $MachinePrecision]}, Block[{t$95$2 = N[Exp[t$95$0], $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[t$95$0], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], (-N[(N[(1.0 / N[(Pi / 4.0), $MachinePrecision]), $MachinePrecision] * N[Log[N[(N[(t$95$1 + t$95$2), $MachinePrecision] / N[(t$95$1 - t$95$2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision])]]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \left(f \cdot \pi\right) \cdot -0.25\\
          t_1 := \mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)\\
          t_2 := e^{t\_0}\\
          \mathbf{if}\;f \leq 23:\\
          \;\;\;\;\left(\frac{\log \cosh t\_0}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\
          
          \mathbf{else}:\\
          \;\;\;\;-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_1 + t\_2}{t\_1 - t\_2}\right)\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if f < 23

            1. Initial program 6.7%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around inf

              \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
            3. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
              2. lower-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
            4. Applied rewrites99.4%

              \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
            5. Step-by-step derivation
              1. lift-/.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              2. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              3. lift-cosh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              4. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              5. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              6. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              7. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              8. lift-sinh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              9. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              10. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              11. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              12. lower-log.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
            6. Applied rewrites99.4%

              \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
            7. Step-by-step derivation
              1. lift-PI.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
              2. lift-/.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
            8. Applied rewrites99.4%

              \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

            if 23 < f

            1. Initial program 3.0%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\left(1 + \frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            3. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lower-fma.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(f \cdot \mathsf{PI}\left(\right), \color{blue}{\frac{1}{4}}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              5. lower-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              6. lift-PI.f641.7

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            4. Applied rewrites1.7%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            5. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\left(1 + \frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            6. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\left(\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lower-fma.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(f \cdot \mathsf{PI}\left(\right), \color{blue}{\frac{1}{4}}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              5. lower-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              6. lift-PI.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            7. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            8. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\color{blue}{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            9. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{1}{4}}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \color{blue}{0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            10. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\color{blue}{\left(f \cdot \pi\right) \cdot 0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            11. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\color{blue}{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right) \]
            12. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{1}{4}}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \color{blue}{0.25}}}\right) \]
            13. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\color{blue}{\left(f \cdot \pi\right) \cdot 0.25}}}\right) \]
            14. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
            15. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{\left(f \cdot \pi\right) \cdot \color{blue}{-0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right) \]
            16. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right) \]
            17. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right) \]
            18. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{\left(f \cdot \pi\right) \cdot -0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{\left(f \cdot \pi\right) \cdot \color{blue}{-0.25}}}\right) \]
            19. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{\left(f \cdot \pi\right) \cdot -0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}}}\right) \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 5: 99.1% accurate, 1.2× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(f \cdot \pi\right) \cdot 0.25\\ t_1 := e^{-t\_0}\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh t\_0}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_0 + t\_1}{t\_0 - t\_1}\right)\\ \end{array} \end{array} \]
          (FPCore (f)
           :precision binary64
           (let* ((t_0 (* (* f PI) 0.25)) (t_1 (exp (- t_0))))
             (if (<= f 23.0)
               (*
                (- (/ (log (cosh (* (* f PI) -0.25))) PI) (/ (log (sinh t_0)) PI))
                -4.0)
               (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ t_0 t_1) (- t_0 t_1))))))))
          double code(double f) {
          	double t_0 = (f * ((double) M_PI)) * 0.25;
          	double t_1 = exp(-t_0);
          	double tmp;
          	if (f <= 23.0) {
          		tmp = ((log(cosh(((f * ((double) M_PI)) * -0.25))) / ((double) M_PI)) - (log(sinh(t_0)) / ((double) M_PI))) * -4.0;
          	} else {
          		tmp = -((1.0 / (((double) M_PI) / 4.0)) * log(((t_0 + t_1) / (t_0 - t_1))));
          	}
          	return tmp;
          }
          
          public static double code(double f) {
          	double t_0 = (f * Math.PI) * 0.25;
          	double t_1 = Math.exp(-t_0);
          	double tmp;
          	if (f <= 23.0) {
          		tmp = ((Math.log(Math.cosh(((f * Math.PI) * -0.25))) / Math.PI) - (Math.log(Math.sinh(t_0)) / Math.PI)) * -4.0;
          	} else {
          		tmp = -((1.0 / (Math.PI / 4.0)) * Math.log(((t_0 + t_1) / (t_0 - t_1))));
          	}
          	return tmp;
          }
          
          def code(f):
          	t_0 = (f * math.pi) * 0.25
          	t_1 = math.exp(-t_0)
          	tmp = 0
          	if f <= 23.0:
          		tmp = ((math.log(math.cosh(((f * math.pi) * -0.25))) / math.pi) - (math.log(math.sinh(t_0)) / math.pi)) * -4.0
          	else:
          		tmp = -((1.0 / (math.pi / 4.0)) * math.log(((t_0 + t_1) / (t_0 - t_1))))
          	return tmp
          
          function code(f)
          	t_0 = Float64(Float64(f * pi) * 0.25)
          	t_1 = exp(Float64(-t_0))
          	tmp = 0.0
          	if (f <= 23.0)
          		tmp = Float64(Float64(Float64(log(cosh(Float64(Float64(f * pi) * -0.25))) / pi) - Float64(log(sinh(t_0)) / pi)) * -4.0);
          	else
          		tmp = Float64(-Float64(Float64(1.0 / Float64(pi / 4.0)) * log(Float64(Float64(t_0 + t_1) / Float64(t_0 - t_1)))));
          	end
          	return tmp
          end
          
          function tmp_2 = code(f)
          	t_0 = (f * pi) * 0.25;
          	t_1 = exp(-t_0);
          	tmp = 0.0;
          	if (f <= 23.0)
          		tmp = ((log(cosh(((f * pi) * -0.25))) / pi) - (log(sinh(t_0)) / pi)) * -4.0;
          	else
          		tmp = -((1.0 / (pi / 4.0)) * log(((t_0 + t_1) / (t_0 - t_1))));
          	end
          	tmp_2 = tmp;
          end
          
          code[f_] := Block[{t$95$0 = N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]}, Block[{t$95$1 = N[Exp[(-t$95$0)], $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[t$95$0], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], (-N[(N[(1.0 / N[(Pi / 4.0), $MachinePrecision]), $MachinePrecision] * N[Log[N[(N[(t$95$0 + t$95$1), $MachinePrecision] / N[(t$95$0 - t$95$1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision])]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \left(f \cdot \pi\right) \cdot 0.25\\
          t_1 := e^{-t\_0}\\
          \mathbf{if}\;f \leq 23:\\
          \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh t\_0}{\pi}\right) \cdot -4\\
          
          \mathbf{else}:\\
          \;\;\;\;-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t\_0 + t\_1}{t\_0 - t\_1}\right)\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if f < 23

            1. Initial program 6.7%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around inf

              \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
            3. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
              2. lower-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
            4. Applied rewrites99.4%

              \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
            5. Step-by-step derivation
              1. lift-/.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              2. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              3. lift-cosh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              4. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              5. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              6. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              7. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              8. lift-sinh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              9. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              10. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              11. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              12. lower-log.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
            6. Applied rewrites99.4%

              \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
            7. Step-by-step derivation
              1. lift-PI.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
              2. lift-/.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
            8. Applied rewrites99.4%

              \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

            if 23 < f

            1. Initial program 3.0%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\left(1 + \frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            3. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lower-fma.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(f \cdot \mathsf{PI}\left(\right), \color{blue}{\frac{1}{4}}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              5. lower-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              6. lift-PI.f641.7

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            4. Applied rewrites1.7%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            5. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\left(1 + \frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            6. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right) + \color{blue}{1}\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\left(\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lower-fma.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(f \cdot \mathsf{PI}\left(\right), \color{blue}{\frac{1}{4}}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              5. lower-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              6. lift-PI.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            7. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right)} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            8. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\color{blue}{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            9. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{1}{4}}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \color{blue}{0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            10. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\color{blue}{\left(f \cdot \pi\right) \cdot 0.25}}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            11. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\color{blue}{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right) \]
            12. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{1}{4}}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \color{blue}{0.25}}}\right) \]
            13. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\color{blue}{\left(f \cdot \pi\right) \cdot 0.25}}}\right) \]
            14. Taylor expanded in f around inf

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\frac{1}{4} \cdot \color{blue}{\left(f \cdot \mathsf{PI}\left(\right)\right)} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
            15. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\mathsf{fma}\left(\pi \cdot f, \frac{1}{4}, 1\right) - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              4. lift-*.f643.0

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot 0.25 + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right) \]
            16. Applied rewrites3.0%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot \color{blue}{0.25} + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\mathsf{fma}\left(\pi \cdot f, 0.25, 1\right) - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right) \]
            17. Taylor expanded in f around inf

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\frac{1}{4} \cdot \color{blue}{\left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
            18. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              2. lift-*.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{4} - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              3. lift-PI.f64N/A

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot \frac{1}{4} + e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}{\left(f \cdot \pi\right) \cdot \frac{1}{4} - e^{-\left(f \cdot \pi\right) \cdot \frac{1}{4}}}\right) \]
              4. lift-*.f6486.1

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot 0.25 + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\left(f \cdot \pi\right) \cdot 0.25 - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right) \]
            19. Applied rewrites86.1%

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\left(f \cdot \pi\right) \cdot 0.25 + e^{-\left(f \cdot \pi\right) \cdot 0.25}}{\left(f \cdot \pi\right) \cdot \color{blue}{0.25} - e^{-\left(f \cdot \pi\right) \cdot 0.25}}\right) \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 6: 99.1% accurate, 1.3× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := e^{\frac{\pi}{4} \cdot \left(-f\right)}\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;\log \left({\left(\frac{t\_0 + 1}{1 - t\_0}\right)}^{\left(-\frac{4}{\pi}\right)}\right)\\ \end{array} \end{array} \]
          (FPCore (f)
           :precision binary64
           (let* ((t_0 (exp (* (/ PI 4.0) (- f)))))
             (if (<= f 23.0)
               (*
                (-
                 (/ (log (cosh (* (* f PI) -0.25))) PI)
                 (/ (log (sinh (* (* f PI) 0.25))) PI))
                -4.0)
               (log (pow (/ (+ t_0 1.0) (- 1.0 t_0)) (- (/ 4.0 PI)))))))
          double code(double f) {
          	double t_0 = exp(((((double) M_PI) / 4.0) * -f));
          	double tmp;
          	if (f <= 23.0) {
          		tmp = ((log(cosh(((f * ((double) M_PI)) * -0.25))) / ((double) M_PI)) - (log(sinh(((f * ((double) M_PI)) * 0.25))) / ((double) M_PI))) * -4.0;
          	} else {
          		tmp = log(pow(((t_0 + 1.0) / (1.0 - t_0)), -(4.0 / ((double) M_PI))));
          	}
          	return tmp;
          }
          
          public static double code(double f) {
          	double t_0 = Math.exp(((Math.PI / 4.0) * -f));
          	double tmp;
          	if (f <= 23.0) {
          		tmp = ((Math.log(Math.cosh(((f * Math.PI) * -0.25))) / Math.PI) - (Math.log(Math.sinh(((f * Math.PI) * 0.25))) / Math.PI)) * -4.0;
          	} else {
          		tmp = Math.log(Math.pow(((t_0 + 1.0) / (1.0 - t_0)), -(4.0 / Math.PI)));
          	}
          	return tmp;
          }
          
          def code(f):
          	t_0 = math.exp(((math.pi / 4.0) * -f))
          	tmp = 0
          	if f <= 23.0:
          		tmp = ((math.log(math.cosh(((f * math.pi) * -0.25))) / math.pi) - (math.log(math.sinh(((f * math.pi) * 0.25))) / math.pi)) * -4.0
          	else:
          		tmp = math.log(math.pow(((t_0 + 1.0) / (1.0 - t_0)), -(4.0 / math.pi)))
          	return tmp
          
          function code(f)
          	t_0 = exp(Float64(Float64(pi / 4.0) * Float64(-f)))
          	tmp = 0.0
          	if (f <= 23.0)
          		tmp = Float64(Float64(Float64(log(cosh(Float64(Float64(f * pi) * -0.25))) / pi) - Float64(log(sinh(Float64(Float64(f * pi) * 0.25))) / pi)) * -4.0);
          	else
          		tmp = log((Float64(Float64(t_0 + 1.0) / Float64(1.0 - t_0)) ^ Float64(-Float64(4.0 / pi))));
          	end
          	return tmp
          end
          
          function tmp_2 = code(f)
          	t_0 = exp(((pi / 4.0) * -f));
          	tmp = 0.0;
          	if (f <= 23.0)
          		tmp = ((log(cosh(((f * pi) * -0.25))) / pi) - (log(sinh(((f * pi) * 0.25))) / pi)) * -4.0;
          	else
          		tmp = log((((t_0 + 1.0) / (1.0 - t_0)) ^ -(4.0 / pi)));
          	end
          	tmp_2 = tmp;
          end
          
          code[f_] := Block[{t$95$0 = N[Exp[N[(N[(Pi / 4.0), $MachinePrecision] * (-f)), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], N[Log[N[Power[N[(N[(t$95$0 + 1.0), $MachinePrecision] / N[(1.0 - t$95$0), $MachinePrecision]), $MachinePrecision], (-N[(4.0 / Pi), $MachinePrecision])], $MachinePrecision]], $MachinePrecision]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := e^{\frac{\pi}{4} \cdot \left(-f\right)}\\
          \mathbf{if}\;f \leq 23:\\
          \;\;\;\;\left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\
          
          \mathbf{else}:\\
          \;\;\;\;\log \left({\left(\frac{t\_0 + 1}{1 - t\_0}\right)}^{\left(-\frac{4}{\pi}\right)}\right)\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if f < 23

            1. Initial program 6.7%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around inf

              \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
            3. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
              2. lower-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
            4. Applied rewrites99.4%

              \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
            5. Step-by-step derivation
              1. lift-/.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              2. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              3. lift-cosh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              4. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              5. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              6. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              7. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              8. lift-sinh.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              9. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              10. lift-PI.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              11. lift-*.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
              12. lower-log.f64N/A

                \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
            6. Applied rewrites99.4%

              \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
            7. Step-by-step derivation
              1. lift-PI.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
              2. lift-/.f64N/A

                \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
            8. Applied rewrites99.4%

              \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

            if 23 < f

            1. Initial program 3.0%

              \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            2. Taylor expanded in f around 0

              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
            3. Step-by-step derivation
              1. Applied rewrites1.7%

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              2. Taylor expanded in f around 0

                \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
              3. Step-by-step derivation
                1. Applied rewrites86.1%

                  \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                2. Step-by-step derivation
                  1. lift-neg.f64N/A

                    \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} \]
                  2. lift-*.f64N/A

                    \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)}\right) \]
                  3. distribute-lft-neg-inN/A

                    \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}}\right)\right) \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)} \]
                  4. lift-log.f64N/A

                    \[\leadsto \left(\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}}\right)\right) \cdot \color{blue}{\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)} \]
                3. Applied rewrites86.1%

                  \[\leadsto \color{blue}{\log \left({\left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)}^{\left(-\frac{4}{\pi}\right)}\right)} \]
              4. Recombined 2 regimes into one program.
              5. Add Preprocessing

              Alternative 7: 99.1% accurate, 1.5× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(f \cdot \pi\right) \cdot -0.25\\ t_1 := e^{t\_0}\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\left(\frac{\log \cosh t\_0}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\ \mathbf{else}:\\ \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_1 + 1}{1 - t\_1}\right)\right)\\ \end{array} \end{array} \]
              (FPCore (f)
               :precision binary64
               (let* ((t_0 (* (* f PI) -0.25)) (t_1 (exp t_0)))
                 (if (<= f 23.0)
                   (* (- (/ (log (cosh t_0)) PI) (/ (log (sinh (* (* f PI) 0.25))) PI)) -4.0)
                   (* (/ 4.0 PI) (- (log (/ (+ t_1 1.0) (- 1.0 t_1))))))))
              double code(double f) {
              	double t_0 = (f * ((double) M_PI)) * -0.25;
              	double t_1 = exp(t_0);
              	double tmp;
              	if (f <= 23.0) {
              		tmp = ((log(cosh(t_0)) / ((double) M_PI)) - (log(sinh(((f * ((double) M_PI)) * 0.25))) / ((double) M_PI))) * -4.0;
              	} else {
              		tmp = (4.0 / ((double) M_PI)) * -log(((t_1 + 1.0) / (1.0 - t_1)));
              	}
              	return tmp;
              }
              
              public static double code(double f) {
              	double t_0 = (f * Math.PI) * -0.25;
              	double t_1 = Math.exp(t_0);
              	double tmp;
              	if (f <= 23.0) {
              		tmp = ((Math.log(Math.cosh(t_0)) / Math.PI) - (Math.log(Math.sinh(((f * Math.PI) * 0.25))) / Math.PI)) * -4.0;
              	} else {
              		tmp = (4.0 / Math.PI) * -Math.log(((t_1 + 1.0) / (1.0 - t_1)));
              	}
              	return tmp;
              }
              
              def code(f):
              	t_0 = (f * math.pi) * -0.25
              	t_1 = math.exp(t_0)
              	tmp = 0
              	if f <= 23.0:
              		tmp = ((math.log(math.cosh(t_0)) / math.pi) - (math.log(math.sinh(((f * math.pi) * 0.25))) / math.pi)) * -4.0
              	else:
              		tmp = (4.0 / math.pi) * -math.log(((t_1 + 1.0) / (1.0 - t_1)))
              	return tmp
              
              function code(f)
              	t_0 = Float64(Float64(f * pi) * -0.25)
              	t_1 = exp(t_0)
              	tmp = 0.0
              	if (f <= 23.0)
              		tmp = Float64(Float64(Float64(log(cosh(t_0)) / pi) - Float64(log(sinh(Float64(Float64(f * pi) * 0.25))) / pi)) * -4.0);
              	else
              		tmp = Float64(Float64(4.0 / pi) * Float64(-log(Float64(Float64(t_1 + 1.0) / Float64(1.0 - t_1)))));
              	end
              	return tmp
              end
              
              function tmp_2 = code(f)
              	t_0 = (f * pi) * -0.25;
              	t_1 = exp(t_0);
              	tmp = 0.0;
              	if (f <= 23.0)
              		tmp = ((log(cosh(t_0)) / pi) - (log(sinh(((f * pi) * 0.25))) / pi)) * -4.0;
              	else
              		tmp = (4.0 / pi) * -log(((t_1 + 1.0) / (1.0 - t_1)));
              	end
              	tmp_2 = tmp;
              end
              
              code[f_] := Block[{t$95$0 = N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]}, Block[{t$95$1 = N[Exp[t$95$0], $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[t$95$0], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] - N[(N[Log[N[Sinh[N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision], N[(N[(4.0 / Pi), $MachinePrecision] * (-N[Log[N[(N[(t$95$1 + 1.0), $MachinePrecision] / N[(1.0 - t$95$1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])), $MachinePrecision]]]]
              
              \begin{array}{l}
              
              \\
              \begin{array}{l}
              t_0 := \left(f \cdot \pi\right) \cdot -0.25\\
              t_1 := e^{t\_0}\\
              \mathbf{if}\;f \leq 23:\\
              \;\;\;\;\left(\frac{\log \cosh t\_0}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4\\
              
              \mathbf{else}:\\
              \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_1 + 1}{1 - t\_1}\right)\right)\\
              
              
              \end{array}
              \end{array}
              
              Derivation
              1. Split input into 2 regimes
              2. if f < 23

                1. Initial program 6.7%

                  \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                2. Taylor expanded in f around inf

                  \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                3. Step-by-step derivation
                  1. *-commutativeN/A

                    \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                  2. lower-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                4. Applied rewrites99.4%

                  \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                5. Step-by-step derivation
                  1. lift-/.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  2. lift-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  3. lift-cosh.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  4. lift-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  5. lift-PI.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  6. lift-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  7. lift-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  8. lift-sinh.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  9. lift-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  10. lift-PI.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  11. lift-*.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                  12. lower-log.f64N/A

                    \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                6. Applied rewrites99.4%

                  \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
                7. Step-by-step derivation
                  1. lift-PI.f64N/A

                    \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
                  2. lift-/.f64N/A

                    \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
                8. Applied rewrites99.4%

                  \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]

                if 23 < f

                1. Initial program 3.0%

                  \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                2. Taylor expanded in f around 0

                  \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                3. Step-by-step derivation
                  1. Applied rewrites1.7%

                    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                  2. Taylor expanded in f around 0

                    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                  3. Step-by-step derivation
                    1. Applied rewrites86.1%

                      \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                    2. Step-by-step derivation
                      1. lift-neg.f64N/A

                        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} \]
                      2. lift-*.f64N/A

                        \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)}\right) \]
                      3. distribute-rgt-neg-inN/A

                        \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
                      4. lower-*.f64N/A

                        \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
                    3. Applied rewrites86.1%

                      \[\leadsto \color{blue}{\frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right)} \]
                    4. Taylor expanded in f around 0

                      \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                    5. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                      2. lower-*.f64N/A

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                      3. lift-*.f64N/A

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                      4. lift-PI.f6486.1

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                    6. Applied rewrites86.1%

                      \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                    7. Taylor expanded in f around 0

                      \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right)\right) \]
                    8. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right)\right) \]
                      2. lower-*.f64N/A

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right)\right) \]
                      3. lift-*.f64N/A

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}}}\right)\right) \]
                      4. lift-PI.f6486.1

                        \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\left(f \cdot \pi\right) \cdot -0.25}}\right)\right) \]
                    9. Applied rewrites86.1%

                      \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}}}\right)\right) \]
                  4. Recombined 2 regimes into one program.
                  5. Add Preprocessing

                  Alternative 8: 99.1% accurate, 1.6× speedup?

                  \[\begin{array}{l} \\ \begin{array}{l} t_0 := e^{\left(f \cdot \pi\right) \cdot -0.25}\\ t_1 := \left(f \cdot \pi\right) \cdot 0.25\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\frac{\log \cosh t\_1 - \log \sinh t\_1}{\pi} \cdot -4\\ \mathbf{else}:\\ \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + 1}{1 - t\_0}\right)\right)\\ \end{array} \end{array} \]
                  (FPCore (f)
                   :precision binary64
                   (let* ((t_0 (exp (* (* f PI) -0.25))) (t_1 (* (* f PI) 0.25)))
                     (if (<= f 23.0)
                       (* (/ (- (log (cosh t_1)) (log (sinh t_1))) PI) -4.0)
                       (* (/ 4.0 PI) (- (log (/ (+ t_0 1.0) (- 1.0 t_0))))))))
                  double code(double f) {
                  	double t_0 = exp(((f * ((double) M_PI)) * -0.25));
                  	double t_1 = (f * ((double) M_PI)) * 0.25;
                  	double tmp;
                  	if (f <= 23.0) {
                  		tmp = ((log(cosh(t_1)) - log(sinh(t_1))) / ((double) M_PI)) * -4.0;
                  	} else {
                  		tmp = (4.0 / ((double) M_PI)) * -log(((t_0 + 1.0) / (1.0 - t_0)));
                  	}
                  	return tmp;
                  }
                  
                  public static double code(double f) {
                  	double t_0 = Math.exp(((f * Math.PI) * -0.25));
                  	double t_1 = (f * Math.PI) * 0.25;
                  	double tmp;
                  	if (f <= 23.0) {
                  		tmp = ((Math.log(Math.cosh(t_1)) - Math.log(Math.sinh(t_1))) / Math.PI) * -4.0;
                  	} else {
                  		tmp = (4.0 / Math.PI) * -Math.log(((t_0 + 1.0) / (1.0 - t_0)));
                  	}
                  	return tmp;
                  }
                  
                  def code(f):
                  	t_0 = math.exp(((f * math.pi) * -0.25))
                  	t_1 = (f * math.pi) * 0.25
                  	tmp = 0
                  	if f <= 23.0:
                  		tmp = ((math.log(math.cosh(t_1)) - math.log(math.sinh(t_1))) / math.pi) * -4.0
                  	else:
                  		tmp = (4.0 / math.pi) * -math.log(((t_0 + 1.0) / (1.0 - t_0)))
                  	return tmp
                  
                  function code(f)
                  	t_0 = exp(Float64(Float64(f * pi) * -0.25))
                  	t_1 = Float64(Float64(f * pi) * 0.25)
                  	tmp = 0.0
                  	if (f <= 23.0)
                  		tmp = Float64(Float64(Float64(log(cosh(t_1)) - log(sinh(t_1))) / pi) * -4.0);
                  	else
                  		tmp = Float64(Float64(4.0 / pi) * Float64(-log(Float64(Float64(t_0 + 1.0) / Float64(1.0 - t_0)))));
                  	end
                  	return tmp
                  end
                  
                  function tmp_2 = code(f)
                  	t_0 = exp(((f * pi) * -0.25));
                  	t_1 = (f * pi) * 0.25;
                  	tmp = 0.0;
                  	if (f <= 23.0)
                  		tmp = ((log(cosh(t_1)) - log(sinh(t_1))) / pi) * -4.0;
                  	else
                  		tmp = (4.0 / pi) * -log(((t_0 + 1.0) / (1.0 - t_0)));
                  	end
                  	tmp_2 = tmp;
                  end
                  
                  code[f_] := Block[{t$95$0 = N[Exp[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[(N[Log[N[Cosh[t$95$1], $MachinePrecision]], $MachinePrecision] - N[Log[N[Sinh[t$95$1], $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision], N[(N[(4.0 / Pi), $MachinePrecision] * (-N[Log[N[(N[(t$95$0 + 1.0), $MachinePrecision] / N[(1.0 - t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])), $MachinePrecision]]]]
                  
                  \begin{array}{l}
                  
                  \\
                  \begin{array}{l}
                  t_0 := e^{\left(f \cdot \pi\right) \cdot -0.25}\\
                  t_1 := \left(f \cdot \pi\right) \cdot 0.25\\
                  \mathbf{if}\;f \leq 23:\\
                  \;\;\;\;\frac{\log \cosh t\_1 - \log \sinh t\_1}{\pi} \cdot -4\\
                  
                  \mathbf{else}:\\
                  \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + 1}{1 - t\_0}\right)\right)\\
                  
                  
                  \end{array}
                  \end{array}
                  
                  Derivation
                  1. Split input into 2 regimes
                  2. if f < 23

                    1. Initial program 6.7%

                      \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                    2. Taylor expanded in f around inf

                      \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                    3. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                      2. lower-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                    4. Applied rewrites99.4%

                      \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                    5. Step-by-step derivation
                      1. lift-/.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      2. lift-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      3. lift-cosh.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      4. lift-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      5. lift-PI.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      6. lift-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      7. lift-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      8. lift-sinh.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      9. lift-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      10. lift-PI.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      11. lift-*.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                      12. lower-log.f64N/A

                        \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                    6. Applied rewrites99.4%

                      \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]

                    if 23 < f

                    1. Initial program 3.0%

                      \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                    2. Taylor expanded in f around 0

                      \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                    3. Step-by-step derivation
                      1. Applied rewrites1.7%

                        \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                      2. Taylor expanded in f around 0

                        \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                      3. Step-by-step derivation
                        1. Applied rewrites86.1%

                          \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                        2. Step-by-step derivation
                          1. lift-neg.f64N/A

                            \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} \]
                          2. lift-*.f64N/A

                            \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)}\right) \]
                          3. distribute-rgt-neg-inN/A

                            \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
                          4. lower-*.f64N/A

                            \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
                        3. Applied rewrites86.1%

                          \[\leadsto \color{blue}{\frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right)} \]
                        4. Taylor expanded in f around 0

                          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                        5. Step-by-step derivation
                          1. *-commutativeN/A

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                          2. lower-*.f64N/A

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                          3. lift-*.f64N/A

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                          4. lift-PI.f6486.1

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                        6. Applied rewrites86.1%

                          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                        7. Taylor expanded in f around 0

                          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right)\right) \]
                        8. Step-by-step derivation
                          1. *-commutativeN/A

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right)\right) \]
                          2. lower-*.f64N/A

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right)\right) \]
                          3. lift-*.f64N/A

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}}}\right)\right) \]
                          4. lift-PI.f6486.1

                            \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\left(f \cdot \pi\right) \cdot -0.25}}\right)\right) \]
                        9. Applied rewrites86.1%

                          \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}}}\right)\right) \]
                      4. Recombined 2 regimes into one program.
                      5. Add Preprocessing

                      Alternative 9: 99.1% accurate, 1.6× speedup?

                      \[\begin{array}{l} \\ \begin{array}{l} t_0 := e^{\left(f \cdot \pi\right) \cdot -0.25}\\ t_1 := \left(f \cdot \pi\right) \cdot 0.25\\ \mathbf{if}\;f \leq 23:\\ \;\;\;\;\frac{\log \left(\frac{\cosh t\_1}{\sinh t\_1}\right) \cdot -4}{\pi}\\ \mathbf{else}:\\ \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + 1}{1 - t\_0}\right)\right)\\ \end{array} \end{array} \]
                      (FPCore (f)
                       :precision binary64
                       (let* ((t_0 (exp (* (* f PI) -0.25))) (t_1 (* (* f PI) 0.25)))
                         (if (<= f 23.0)
                           (/ (* (log (/ (cosh t_1) (sinh t_1))) -4.0) PI)
                           (* (/ 4.0 PI) (- (log (/ (+ t_0 1.0) (- 1.0 t_0))))))))
                      double code(double f) {
                      	double t_0 = exp(((f * ((double) M_PI)) * -0.25));
                      	double t_1 = (f * ((double) M_PI)) * 0.25;
                      	double tmp;
                      	if (f <= 23.0) {
                      		tmp = (log((cosh(t_1) / sinh(t_1))) * -4.0) / ((double) M_PI);
                      	} else {
                      		tmp = (4.0 / ((double) M_PI)) * -log(((t_0 + 1.0) / (1.0 - t_0)));
                      	}
                      	return tmp;
                      }
                      
                      public static double code(double f) {
                      	double t_0 = Math.exp(((f * Math.PI) * -0.25));
                      	double t_1 = (f * Math.PI) * 0.25;
                      	double tmp;
                      	if (f <= 23.0) {
                      		tmp = (Math.log((Math.cosh(t_1) / Math.sinh(t_1))) * -4.0) / Math.PI;
                      	} else {
                      		tmp = (4.0 / Math.PI) * -Math.log(((t_0 + 1.0) / (1.0 - t_0)));
                      	}
                      	return tmp;
                      }
                      
                      def code(f):
                      	t_0 = math.exp(((f * math.pi) * -0.25))
                      	t_1 = (f * math.pi) * 0.25
                      	tmp = 0
                      	if f <= 23.0:
                      		tmp = (math.log((math.cosh(t_1) / math.sinh(t_1))) * -4.0) / math.pi
                      	else:
                      		tmp = (4.0 / math.pi) * -math.log(((t_0 + 1.0) / (1.0 - t_0)))
                      	return tmp
                      
                      function code(f)
                      	t_0 = exp(Float64(Float64(f * pi) * -0.25))
                      	t_1 = Float64(Float64(f * pi) * 0.25)
                      	tmp = 0.0
                      	if (f <= 23.0)
                      		tmp = Float64(Float64(log(Float64(cosh(t_1) / sinh(t_1))) * -4.0) / pi);
                      	else
                      		tmp = Float64(Float64(4.0 / pi) * Float64(-log(Float64(Float64(t_0 + 1.0) / Float64(1.0 - t_0)))));
                      	end
                      	return tmp
                      end
                      
                      function tmp_2 = code(f)
                      	t_0 = exp(((f * pi) * -0.25));
                      	t_1 = (f * pi) * 0.25;
                      	tmp = 0.0;
                      	if (f <= 23.0)
                      		tmp = (log((cosh(t_1) / sinh(t_1))) * -4.0) / pi;
                      	else
                      		tmp = (4.0 / pi) * -log(((t_0 + 1.0) / (1.0 - t_0)));
                      	end
                      	tmp_2 = tmp;
                      end
                      
                      code[f_] := Block[{t$95$0 = N[Exp[N[(N[(f * Pi), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]}, If[LessEqual[f, 23.0], N[(N[(N[Log[N[(N[Cosh[t$95$1], $MachinePrecision] / N[Sinh[t$95$1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * -4.0), $MachinePrecision] / Pi), $MachinePrecision], N[(N[(4.0 / Pi), $MachinePrecision] * (-N[Log[N[(N[(t$95$0 + 1.0), $MachinePrecision] / N[(1.0 - t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])), $MachinePrecision]]]]
                      
                      \begin{array}{l}
                      
                      \\
                      \begin{array}{l}
                      t_0 := e^{\left(f \cdot \pi\right) \cdot -0.25}\\
                      t_1 := \left(f \cdot \pi\right) \cdot 0.25\\
                      \mathbf{if}\;f \leq 23:\\
                      \;\;\;\;\frac{\log \left(\frac{\cosh t\_1}{\sinh t\_1}\right) \cdot -4}{\pi}\\
                      
                      \mathbf{else}:\\
                      \;\;\;\;\frac{4}{\pi} \cdot \left(-\log \left(\frac{t\_0 + 1}{1 - t\_0}\right)\right)\\
                      
                      
                      \end{array}
                      \end{array}
                      
                      Derivation
                      1. Split input into 2 regimes
                      2. if f < 23

                        1. Initial program 6.7%

                          \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                        2. Taylor expanded in f around inf

                          \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                        3. Step-by-step derivation
                          1. *-commutativeN/A

                            \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          2. lower-*.f64N/A

                            \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                        4. Applied rewrites99.4%

                          \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                        5. Applied rewrites99.4%

                          \[\leadsto \frac{\log \left(\frac{\cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}\right) \cdot -4}{\color{blue}{\pi}} \]

                        if 23 < f

                        1. Initial program 3.0%

                          \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                        2. Taylor expanded in f around 0

                          \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                        3. Step-by-step derivation
                          1. Applied rewrites1.7%

                            \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{1} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around 0

                            \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          3. Step-by-step derivation
                            1. Applied rewrites86.1%

                              \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{1} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                            2. Step-by-step derivation
                              1. lift-neg.f64N/A

                                \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} \]
                              2. lift-*.f64N/A

                                \[\leadsto \mathsf{neg}\left(\color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)}\right) \]
                              3. distribute-rgt-neg-inN/A

                                \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
                              4. lower-*.f64N/A

                                \[\leadsto \color{blue}{\frac{1}{\frac{\pi}{4}} \cdot \left(\mathsf{neg}\left(\log \left(\frac{1 + e^{-\frac{\pi}{4} \cdot f}}{1 - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
                            3. Applied rewrites86.1%

                              \[\leadsto \color{blue}{\frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\frac{\pi}{4} \cdot \left(-f\right)} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right)} \]
                            4. Taylor expanded in f around 0

                              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                            5. Step-by-step derivation
                              1. *-commutativeN/A

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                              2. lower-*.f64N/A

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                              3. lift-*.f64N/A

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                              4. lift-PI.f6486.1

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                            6. Applied rewrites86.1%

                              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}} + 1}{1 - e^{\frac{\pi}{4} \cdot \left(-f\right)}}\right)\right) \]
                            7. Taylor expanded in f around 0

                              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\color{blue}{\frac{-1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}}\right)\right) \]
                            8. Step-by-step derivation
                              1. *-commutativeN/A

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right)\right) \]
                              2. lower-*.f64N/A

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \color{blue}{\frac{-1}{4}}}}\right)\right) \]
                              3. lift-*.f64N/A

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot \frac{-1}{4}} + 1}{1 - e^{\left(f \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{-1}{4}}}\right)\right) \]
                              4. lift-PI.f6486.1

                                \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\left(f \cdot \pi\right) \cdot -0.25}}\right)\right) \]
                            9. Applied rewrites86.1%

                              \[\leadsto \frac{4}{\pi} \cdot \left(-\log \left(\frac{e^{\left(f \cdot \pi\right) \cdot -0.25} + 1}{1 - e^{\color{blue}{\left(f \cdot \pi\right) \cdot -0.25}}}\right)\right) \]
                          4. Recombined 2 regimes into one program.
                          5. Add Preprocessing

                          Alternative 10: 97.2% accurate, 1.8× speedup?

                          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(f \cdot \pi\right) \cdot 0.25\\ \frac{\log \left(\frac{\cosh t\_0}{\sinh t\_0}\right) \cdot -4}{\pi} \end{array} \end{array} \]
                          (FPCore (f)
                           :precision binary64
                           (let* ((t_0 (* (* f PI) 0.25)))
                             (/ (* (log (/ (cosh t_0) (sinh t_0))) -4.0) PI)))
                          double code(double f) {
                          	double t_0 = (f * ((double) M_PI)) * 0.25;
                          	return (log((cosh(t_0) / sinh(t_0))) * -4.0) / ((double) M_PI);
                          }
                          
                          public static double code(double f) {
                          	double t_0 = (f * Math.PI) * 0.25;
                          	return (Math.log((Math.cosh(t_0) / Math.sinh(t_0))) * -4.0) / Math.PI;
                          }
                          
                          def code(f):
                          	t_0 = (f * math.pi) * 0.25
                          	return (math.log((math.cosh(t_0) / math.sinh(t_0))) * -4.0) / math.pi
                          
                          function code(f)
                          	t_0 = Float64(Float64(f * pi) * 0.25)
                          	return Float64(Float64(log(Float64(cosh(t_0) / sinh(t_0))) * -4.0) / pi)
                          end
                          
                          function tmp = code(f)
                          	t_0 = (f * pi) * 0.25;
                          	tmp = (log((cosh(t_0) / sinh(t_0))) * -4.0) / pi;
                          end
                          
                          code[f_] := Block[{t$95$0 = N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]}, N[(N[(N[Log[N[(N[Cosh[t$95$0], $MachinePrecision] / N[Sinh[t$95$0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * -4.0), $MachinePrecision] / Pi), $MachinePrecision]]
                          
                          \begin{array}{l}
                          
                          \\
                          \begin{array}{l}
                          t_0 := \left(f \cdot \pi\right) \cdot 0.25\\
                          \frac{\log \left(\frac{\cosh t\_0}{\sinh t\_0}\right) \cdot -4}{\pi}
                          \end{array}
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around inf

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites97.2%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                          5. Applied rewrites97.2%

                            \[\leadsto \frac{\log \left(\frac{\cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}\right) \cdot -4}{\color{blue}{\pi}} \]
                          6. Add Preprocessing

                          Alternative 11: 96.6% accurate, 2.2× speedup?

                          \[\begin{array}{l} \\ \left(\left(\left(f \cdot f\right) \cdot \pi\right) \cdot 0.03125 - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \end{array} \]
                          (FPCore (f)
                           :precision binary64
                           (* (- (* (* (* f f) PI) 0.03125) (/ (log (sinh (* (* f PI) 0.25))) PI)) -4.0))
                          double code(double f) {
                          	return ((((f * f) * ((double) M_PI)) * 0.03125) - (log(sinh(((f * ((double) M_PI)) * 0.25))) / ((double) M_PI))) * -4.0;
                          }
                          
                          public static double code(double f) {
                          	return ((((f * f) * Math.PI) * 0.03125) - (Math.log(Math.sinh(((f * Math.PI) * 0.25))) / Math.PI)) * -4.0;
                          }
                          
                          def code(f):
                          	return ((((f * f) * math.pi) * 0.03125) - (math.log(math.sinh(((f * math.pi) * 0.25))) / math.pi)) * -4.0
                          
                          function code(f)
                          	return Float64(Float64(Float64(Float64(Float64(f * f) * pi) * 0.03125) - Float64(log(sinh(Float64(Float64(f * pi) * 0.25))) / pi)) * -4.0)
                          end
                          
                          function tmp = code(f)
                          	tmp = ((((f * f) * pi) * 0.03125) - (log(sinh(((f * pi) * 0.25))) / pi)) * -4.0;
                          end
                          
                          code[f_] := N[(N[(N[(N[(N[(f * f), $MachinePrecision] * Pi), $MachinePrecision] * 0.03125), $MachinePrecision] - N[(N[Log[N[Sinh[N[(N[(f * Pi), $MachinePrecision] * 0.25), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] * -4.0), $MachinePrecision]
                          
                          \begin{array}{l}
                          
                          \\
                          \left(\left(\left(f \cdot f\right) \cdot \pi\right) \cdot 0.03125 - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around inf

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites97.2%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                          5. Step-by-step derivation
                            1. lift-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            2. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            3. lift-cosh.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            4. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            5. lift-PI.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            6. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            7. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            8. lift-sinh.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            9. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            10. lift-PI.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            11. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            12. lower-log.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                          6. Applied rewrites97.2%

                            \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
                          7. Step-by-step derivation
                            1. lift-PI.f64N/A

                              \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
                            2. lift-/.f64N/A

                              \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\mathsf{PI}\left(\right)} \cdot -4 \]
                          8. Applied rewrites97.2%

                            \[\leadsto \left(\frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot -0.25\right)}{\pi} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]
                          9. Taylor expanded in f around 0

                            \[\leadsto \left(\frac{1}{32} \cdot \left({f}^{2} \cdot \mathsf{PI}\left(\right)\right) - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\pi}\right) \cdot -4 \]
                          10. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \left(\left({f}^{2} \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{32} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\pi}\right) \cdot -4 \]
                            2. lower-*.f64N/A

                              \[\leadsto \left(\left({f}^{2} \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{32} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\pi}\right) \cdot -4 \]
                            3. lower-*.f64N/A

                              \[\leadsto \left(\left({f}^{2} \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{32} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\pi}\right) \cdot -4 \]
                            4. unpow2N/A

                              \[\leadsto \left(\left(\left(f \cdot f\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{32} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\pi}\right) \cdot -4 \]
                            5. lower-*.f64N/A

                              \[\leadsto \left(\left(\left(f \cdot f\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{1}{32} - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot \frac{1}{4}\right)}{\pi}\right) \cdot -4 \]
                            6. lift-PI.f6496.6

                              \[\leadsto \left(\left(\left(f \cdot f\right) \cdot \pi\right) \cdot 0.03125 - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]
                          11. Applied rewrites96.6%

                            \[\leadsto \left(\left(\left(f \cdot f\right) \cdot \pi\right) \cdot 0.03125 - \frac{\log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi}\right) \cdot -4 \]
                          12. Add Preprocessing

                          Alternative 12: 96.2% accurate, 2.2× speedup?

                          \[\begin{array}{l} \\ \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{\left(0.5 \cdot \pi\right) \cdot f}\right)}{\pi} \cdot -4 \end{array} \]
                          (FPCore (f)
                           :precision binary64
                           (* (/ (log (/ (* 2.0 (cosh (* (* PI f) -0.25))) (* (* 0.5 PI) f))) PI) -4.0))
                          double code(double f) {
                          	return (log(((2.0 * cosh(((((double) M_PI) * f) * -0.25))) / ((0.5 * ((double) M_PI)) * f))) / ((double) M_PI)) * -4.0;
                          }
                          
                          public static double code(double f) {
                          	return (Math.log(((2.0 * Math.cosh(((Math.PI * f) * -0.25))) / ((0.5 * Math.PI) * f))) / Math.PI) * -4.0;
                          }
                          
                          def code(f):
                          	return (math.log(((2.0 * math.cosh(((math.pi * f) * -0.25))) / ((0.5 * math.pi) * f))) / math.pi) * -4.0
                          
                          function code(f)
                          	return Float64(Float64(log(Float64(Float64(2.0 * cosh(Float64(Float64(pi * f) * -0.25))) / Float64(Float64(0.5 * pi) * f))) / pi) * -4.0)
                          end
                          
                          function tmp = code(f)
                          	tmp = (log(((2.0 * cosh(((pi * f) * -0.25))) / ((0.5 * pi) * f))) / pi) * -4.0;
                          end
                          
                          code[f_] := N[(N[(N[Log[N[(N[(2.0 * N[Cosh[N[(N[(Pi * f), $MachinePrecision] * -0.25), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(N[(0.5 * Pi), $MachinePrecision] * f), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
                          
                          \begin{array}{l}
                          
                          \\
                          \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{\left(0.5 \cdot \pi\right) \cdot f}\right)}{\pi} \cdot -4
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around inf

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites97.2%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                          5. Taylor expanded in f around 0

                            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{f \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right)}\right)}{\pi} \cdot -4 \]
                          6. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            3. distribute-rgt-out--N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{\left(\mathsf{PI}\left(\right) \cdot \left(\frac{1}{4} - \frac{-1}{4}\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            4. metadata-evalN/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{\left(\mathsf{PI}\left(\right) \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            5. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{\left(\frac{1}{2} \cdot \mathsf{PI}\left(\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            6. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{\left(\frac{1}{2} \cdot \mathsf{PI}\left(\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            7. lift-PI.f6496.2

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{\left(0.5 \cdot \pi\right) \cdot f}\right)}{\pi} \cdot -4 \]
                          7. Applied rewrites96.2%

                            \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{\left(0.5 \cdot \pi\right) \cdot f}\right)}{\pi} \cdot -4 \]
                          8. Add Preprocessing

                          Alternative 13: 96.2% accurate, 3.4× speedup?

                          \[\begin{array}{l} \\ \frac{\log \left(\frac{2}{0.5 \cdot \pi}\right) - \log f}{\pi} \cdot -4 \end{array} \]
                          (FPCore (f)
                           :precision binary64
                           (* (/ (- (log (/ 2.0 (* 0.5 PI))) (log f)) PI) -4.0))
                          double code(double f) {
                          	return ((log((2.0 / (0.5 * ((double) M_PI)))) - log(f)) / ((double) M_PI)) * -4.0;
                          }
                          
                          public static double code(double f) {
                          	return ((Math.log((2.0 / (0.5 * Math.PI))) - Math.log(f)) / Math.PI) * -4.0;
                          }
                          
                          def code(f):
                          	return ((math.log((2.0 / (0.5 * math.pi))) - math.log(f)) / math.pi) * -4.0
                          
                          function code(f)
                          	return Float64(Float64(Float64(log(Float64(2.0 / Float64(0.5 * pi))) - log(f)) / pi) * -4.0)
                          end
                          
                          function tmp = code(f)
                          	tmp = ((log((2.0 / (0.5 * pi))) - log(f)) / pi) * -4.0;
                          end
                          
                          code[f_] := N[(N[(N[(N[Log[N[(2.0 / N[(0.5 * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[Log[f], $MachinePrecision]), $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
                          
                          \begin{array}{l}
                          
                          \\
                          \frac{\log \left(\frac{2}{0.5 \cdot \pi}\right) - \log f}{\pi} \cdot -4
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around 0

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites96.1%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2}{\left(\pi \cdot 0.5\right) \cdot f}\right)}{\pi} \cdot -4} \]
                          5. Step-by-step derivation
                            1. lift-log.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\pi \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            2. lift-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\pi \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            3. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\pi \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            4. lift-PI.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\mathsf{PI}\left(\right) \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            5. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\mathsf{PI}\left(\right) \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            6. metadata-evalN/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\mathsf{PI}\left(\right) \cdot \left(\frac{1}{4} - \frac{-1}{4}\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            7. distribute-rgt-out--N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            8. associate-/r*N/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}}{f}\right)}{\pi} \cdot -4 \]
                            9. metadata-evalN/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2 \cdot 1}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}}{f}\right)}{\pi} \cdot -4 \]
                            10. associate-*r/N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \frac{1}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}}{f}\right)}{\pi} \cdot -4 \]
                            11. log-divN/A

                              \[\leadsto \frac{\log \left(2 \cdot \frac{1}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) - \log f}{\pi} \cdot -4 \]
                            12. associate-*r/N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot 1}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) - \log f}{\pi} \cdot -4 \]
                            13. metadata-evalN/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) - \log f}{\pi} \cdot -4 \]
                          6. Applied rewrites96.2%

                            \[\leadsto \frac{\log \left(\frac{2}{0.5 \cdot \pi}\right) - \log f}{\pi} \cdot -4 \]
                          7. Add Preprocessing

                          Alternative 14: 96.1% accurate, 4.1× speedup?

                          \[\begin{array}{l} \\ \frac{\log \left(\frac{\frac{2}{f}}{0.5 \cdot \pi}\right)}{\pi} \cdot -4 \end{array} \]
                          (FPCore (f) :precision binary64 (* (/ (log (/ (/ 2.0 f) (* 0.5 PI))) PI) -4.0))
                          double code(double f) {
                          	return (log(((2.0 / f) / (0.5 * ((double) M_PI)))) / ((double) M_PI)) * -4.0;
                          }
                          
                          public static double code(double f) {
                          	return (Math.log(((2.0 / f) / (0.5 * Math.PI))) / Math.PI) * -4.0;
                          }
                          
                          def code(f):
                          	return (math.log(((2.0 / f) / (0.5 * math.pi))) / math.pi) * -4.0
                          
                          function code(f)
                          	return Float64(Float64(log(Float64(Float64(2.0 / f) / Float64(0.5 * pi))) / pi) * -4.0)
                          end
                          
                          function tmp = code(f)
                          	tmp = (log(((2.0 / f) / (0.5 * pi))) / pi) * -4.0;
                          end
                          
                          code[f_] := N[(N[(N[Log[N[(N[(2.0 / f), $MachinePrecision] / N[(0.5 * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
                          
                          \begin{array}{l}
                          
                          \\
                          \frac{\log \left(\frac{\frac{2}{f}}{0.5 \cdot \pi}\right)}{\pi} \cdot -4
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around 0

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites96.1%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2}{\left(\pi \cdot 0.5\right) \cdot f}\right)}{\pi} \cdot -4} \]
                          5. Step-by-step derivation
                            1. lift-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\pi \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            2. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\pi \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            3. lift-PI.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\mathsf{PI}\left(\right) \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            4. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\mathsf{PI}\left(\right) \cdot \frac{1}{2}\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            5. metadata-evalN/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\mathsf{PI}\left(\right) \cdot \left(\frac{1}{4} - \frac{-1}{4}\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            6. distribute-rgt-out--N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right) \cdot f}\right)}{\pi} \cdot -4 \]
                            7. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{2}{f \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right)}\right)}{\pi} \cdot -4 \]
                            8. associate-/r*N/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            9. lower-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            10. lower-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            11. distribute-rgt-out--N/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\mathsf{PI}\left(\right) \cdot \left(\frac{1}{4} - \frac{-1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            12. metadata-evalN/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\mathsf{PI}\left(\right) \cdot \frac{1}{2}}\right)}{\pi} \cdot -4 \]
                            13. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\frac{1}{2} \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            14. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{\frac{1}{2} \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            15. lift-PI.f6496.1

                              \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{0.5 \cdot \pi}\right)}{\pi} \cdot -4 \]
                          6. Applied rewrites96.1%

                            \[\leadsto \frac{\log \left(\frac{\frac{2}{f}}{0.5 \cdot \pi}\right)}{\pi} \cdot -4 \]
                          7. Add Preprocessing

                          Alternative 15: 96.1% accurate, 4.3× speedup?

                          \[\begin{array}{l} \\ \frac{\log \left(\left(\left(0.5 \cdot \pi\right) \cdot 0.5\right) \cdot f\right)}{\pi} \cdot 4 \end{array} \]
                          (FPCore (f) :precision binary64 (* (/ (log (* (* (* 0.5 PI) 0.5) f)) PI) 4.0))
                          double code(double f) {
                          	return (log((((0.5 * ((double) M_PI)) * 0.5) * f)) / ((double) M_PI)) * 4.0;
                          }
                          
                          public static double code(double f) {
                          	return (Math.log((((0.5 * Math.PI) * 0.5) * f)) / Math.PI) * 4.0;
                          }
                          
                          def code(f):
                          	return (math.log((((0.5 * math.pi) * 0.5) * f)) / math.pi) * 4.0
                          
                          function code(f)
                          	return Float64(Float64(log(Float64(Float64(Float64(0.5 * pi) * 0.5) * f)) / pi) * 4.0)
                          end
                          
                          function tmp = code(f)
                          	tmp = (log((((0.5 * pi) * 0.5) * f)) / pi) * 4.0;
                          end
                          
                          code[f_] := N[(N[(N[Log[N[(N[(N[(0.5 * Pi), $MachinePrecision] * 0.5), $MachinePrecision] * f), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * 4.0), $MachinePrecision]
                          
                          \begin{array}{l}
                          
                          \\
                          \frac{\log \left(\left(\left(0.5 \cdot \pi\right) \cdot 0.5\right) \cdot f\right)}{\pi} \cdot 4
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around inf

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)} + e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)}}{e^{\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)} - e^{\mathsf{neg}\left(\frac{1}{4} \cdot \left(f \cdot \mathsf{PI}\left(\right)\right)\right)}}\right)}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites97.2%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot -0.25\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot 0.25\right)}\right)}{\pi} \cdot -4} \]
                          5. Step-by-step derivation
                            1. lift-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            2. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            3. lift-cosh.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            4. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\pi \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            5. lift-PI.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            6. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            7. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            8. lift-sinh.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            9. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\pi \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            10. lift-PI.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            11. lift-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                            12. lower-log.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2 \cdot \cosh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{-1}{4}\right)}{2 \cdot \sinh \left(\left(\mathsf{PI}\left(\right) \cdot f\right) \cdot \frac{1}{4}\right)}\right)}{\pi} \cdot -4 \]
                          6. Applied rewrites97.2%

                            \[\leadsto \frac{\log \cosh \left(\left(f \cdot \pi\right) \cdot 0.25\right) - \log \sinh \left(\left(f \cdot \pi\right) \cdot 0.25\right)}{\pi} \cdot -4 \]
                          7. Taylor expanded in f around 0

                            \[\leadsto 4 \cdot \color{blue}{\frac{\log f + \log \left(\frac{1}{2} \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right)\right)}{\mathsf{PI}\left(\right)}} \]
                          8. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log f + \log \left(\frac{1}{2} \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right)\right)}{\mathsf{PI}\left(\right)} \cdot 4 \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log f + \log \left(\frac{1}{2} \cdot \left(\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)\right)\right)}{\mathsf{PI}\left(\right)} \cdot 4 \]
                          9. Applied rewrites96.1%

                            \[\leadsto \frac{\log \left(\left(\left(0.5 \cdot \pi\right) \cdot 0.5\right) \cdot f\right)}{\pi} \cdot \color{blue}{4} \]
                          10. Add Preprocessing

                          Alternative 16: 96.1% accurate, 4.8× speedup?

                          \[\begin{array}{l} \\ \frac{\log \left(\frac{4}{f \cdot \pi}\right)}{\pi} \cdot -4 \end{array} \]
                          (FPCore (f) :precision binary64 (* (/ (log (/ 4.0 (* f PI))) PI) -4.0))
                          double code(double f) {
                          	return (log((4.0 / (f * ((double) M_PI)))) / ((double) M_PI)) * -4.0;
                          }
                          
                          public static double code(double f) {
                          	return (Math.log((4.0 / (f * Math.PI))) / Math.PI) * -4.0;
                          }
                          
                          def code(f):
                          	return (math.log((4.0 / (f * math.pi))) / math.pi) * -4.0
                          
                          function code(f)
                          	return Float64(Float64(log(Float64(4.0 / Float64(f * pi))) / pi) * -4.0)
                          end
                          
                          function tmp = code(f)
                          	tmp = (log((4.0 / (f * pi))) / pi) * -4.0;
                          end
                          
                          code[f_] := N[(N[(N[Log[N[(4.0 / N[(f * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
                          
                          \begin{array}{l}
                          
                          \\
                          \frac{\log \left(\frac{4}{f \cdot \pi}\right)}{\pi} \cdot -4
                          \end{array}
                          
                          Derivation
                          1. Initial program 6.7%

                            \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
                          2. Taylor expanded in f around 0

                            \[\leadsto \color{blue}{-4 \cdot \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)}} \]
                          3. Step-by-step derivation
                            1. *-commutativeN/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{2}{\frac{1}{4} \cdot \mathsf{PI}\left(\right) - \frac{-1}{4} \cdot \mathsf{PI}\left(\right)}\right) + -1 \cdot \log f}{\mathsf{PI}\left(\right)} \cdot \color{blue}{-4} \]
                          4. Applied rewrites96.1%

                            \[\leadsto \color{blue}{\frac{\log \left(\frac{2}{\left(\pi \cdot 0.5\right) \cdot f}\right)}{\pi} \cdot -4} \]
                          5. Taylor expanded in f around 0

                            \[\leadsto \frac{\log \left(\frac{4}{f \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                          6. Step-by-step derivation
                            1. lower-/.f64N/A

                              \[\leadsto \frac{\log \left(\frac{4}{f \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            2. lower-*.f64N/A

                              \[\leadsto \frac{\log \left(\frac{4}{f \cdot \mathsf{PI}\left(\right)}\right)}{\pi} \cdot -4 \]
                            3. lift-PI.f6496.1

                              \[\leadsto \frac{\log \left(\frac{4}{f \cdot \pi}\right)}{\pi} \cdot -4 \]
                          7. Applied rewrites96.1%

                            \[\leadsto \frac{\log \left(\frac{4}{f \cdot \pi}\right)}{\pi} \cdot -4 \]
                          8. Add Preprocessing

                          Reproduce

                          ?
                          herbie shell --seed 2025115 
                          (FPCore (f)
                            :name "VandenBroeck and Keller, Equation (20)"
                            :precision binary64
                            (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ (exp (* (/ PI 4.0) f)) (exp (- (* (/ PI 4.0) f)))) (- (exp (* (/ PI 4.0) f)) (exp (- (* (/ PI 4.0) f)))))))))