VandenBroeck and Keller, Equation (6)

Percentage Accurate: 76.8% → 82.4%
Time: 1.6min
Alternatives: 7
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \end{array} \]
(FPCore (F l)
 :precision binary64
 (- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))
double code(double F, double l) {
	return (((double) M_PI) * l) - ((1.0 / (F * F)) * tan((((double) M_PI) * l)));
}
public static double code(double F, double l) {
	return (Math.PI * l) - ((1.0 / (F * F)) * Math.tan((Math.PI * l)));
}
def code(F, l):
	return (math.pi * l) - ((1.0 / (F * F)) * math.tan((math.pi * l)))
function code(F, l)
	return Float64(Float64(pi * l) - Float64(Float64(1.0 / Float64(F * F)) * tan(Float64(pi * l))))
end
function tmp = code(F, l)
	tmp = (pi * l) - ((1.0 / (F * F)) * tan((pi * l)));
end
code[F_, l_] := N[(N[(Pi * l), $MachinePrecision] - N[(N[(1.0 / N[(F * F), $MachinePrecision]), $MachinePrecision] * N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)
\end{array}

Sampling outcomes in binary64 precision:

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 7 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: 76.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \end{array} \]
(FPCore (F l)
 :precision binary64
 (- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))
double code(double F, double l) {
	return (((double) M_PI) * l) - ((1.0 / (F * F)) * tan((((double) M_PI) * l)));
}
public static double code(double F, double l) {
	return (Math.PI * l) - ((1.0 / (F * F)) * Math.tan((Math.PI * l)));
}
def code(F, l):
	return (math.pi * l) - ((1.0 / (F * F)) * math.tan((math.pi * l)))
function code(F, l)
	return Float64(Float64(pi * l) - Float64(Float64(1.0 / Float64(F * F)) * tan(Float64(pi * l))))
end
function tmp = code(F, l)
	tmp = (pi * l) - ((1.0 / (F * F)) * tan((pi * l)));
end
code[F_, l_] := N[(N[(Pi * l), $MachinePrecision] - N[(N[(1.0 / N[(F * F), $MachinePrecision]), $MachinePrecision] * N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)
\end{array}

Alternative 1: 82.4% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\ell \cdot \sqrt[3]{{\pi}^{3}}\right)}{F}}{-F}\right) \end{array} \]
(FPCore (F l)
 :precision binary64
 (fma PI l (/ (/ (tan (* l (cbrt (pow PI 3.0)))) F) (- F))))
double code(double F, double l) {
	return fma(((double) M_PI), l, ((tan((l * cbrt(pow(((double) M_PI), 3.0)))) / F) / -F));
}
function code(F, l)
	return fma(pi, l, Float64(Float64(tan(Float64(l * cbrt((pi ^ 3.0)))) / F) / Float64(-F)))
end
code[F_, l_] := N[(Pi * l + N[(N[(N[Tan[N[(l * N[Power[N[Power[Pi, 3.0], $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / F), $MachinePrecision] / (-F)), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\ell \cdot \sqrt[3]{{\pi}^{3}}\right)}{F}}{-F}\right)
\end{array}
Derivation
  1. Initial program 76.7%

    \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
  2. Step-by-step derivation
    1. fma-neg76.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, -\frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\right)} \]
    2. distribute-lft-neg-in76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\left(-\frac{1}{F \cdot F}\right) \cdot \tan \left(\pi \cdot \ell\right)}\right) \]
    3. sqr-neg76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \left(-\frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}}\right) \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    4. distribute-neg-frac76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{-1}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    5. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{-1}}{\left(-F\right) \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    6. distribute-lft-neg-out76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    7. neg-mul-176.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-1 \cdot \left(F \cdot \left(-F\right)\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    8. associate-/r*76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{-1}{-1}}{F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    9. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{1}}{F \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    10. associate-*l/77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{F \cdot \left(-F\right)}}\right) \]
    11. *-lft-identity77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{F \cdot \left(-F\right)}\right) \]
    12. associate-/r*83.6%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}}\right) \]
  3. Simplified83.6%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. add-cbrt-cube83.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\color{blue}{\sqrt[3]{\left(\pi \cdot \pi\right) \cdot \pi}} \cdot \ell\right)}{F}}{-F}\right) \]
    2. pow383.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\sqrt[3]{\color{blue}{{\pi}^{3}}} \cdot \ell\right)}{F}}{-F}\right) \]
  6. Applied egg-rr83.7%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\color{blue}{\sqrt[3]{{\pi}^{3}}} \cdot \ell\right)}{F}}{-F}\right) \]
  7. Final simplification83.7%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\ell \cdot \sqrt[3]{{\pi}^{3}}\right)}{F}}{-F}\right) \]
  8. Add Preprocessing

Alternative 2: 82.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\pi, \ell, \frac{\frac{1}{F} \cdot \tan \left(\pi \cdot \ell\right)}{-F}\right) \end{array} \]
(FPCore (F l)
 :precision binary64
 (fma PI l (/ (* (/ 1.0 F) (tan (* PI l))) (- F))))
double code(double F, double l) {
	return fma(((double) M_PI), l, (((1.0 / F) * tan((((double) M_PI) * l))) / -F));
}
function code(F, l)
	return fma(pi, l, Float64(Float64(Float64(1.0 / F) * tan(Float64(pi * l))) / Float64(-F)))
end
code[F_, l_] := N[(Pi * l + N[(N[(N[(1.0 / F), $MachinePrecision] * N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / (-F)), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\pi, \ell, \frac{\frac{1}{F} \cdot \tan \left(\pi \cdot \ell\right)}{-F}\right)
\end{array}
Derivation
  1. Initial program 76.7%

    \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
  2. Step-by-step derivation
    1. fma-neg76.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, -\frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\right)} \]
    2. distribute-lft-neg-in76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\left(-\frac{1}{F \cdot F}\right) \cdot \tan \left(\pi \cdot \ell\right)}\right) \]
    3. sqr-neg76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \left(-\frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}}\right) \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    4. distribute-neg-frac76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{-1}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    5. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{-1}}{\left(-F\right) \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    6. distribute-lft-neg-out76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    7. neg-mul-176.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-1 \cdot \left(F \cdot \left(-F\right)\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    8. associate-/r*76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{-1}{-1}}{F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    9. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{1}}{F \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    10. associate-*l/77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{F \cdot \left(-F\right)}}\right) \]
    11. *-lft-identity77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{F \cdot \left(-F\right)}\right) \]
    12. associate-/r*83.6%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}}\right) \]
  3. Simplified83.6%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. clear-num83.6%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{1}{\frac{F}{\tan \left(\pi \cdot \ell\right)}}}}{-F}\right) \]
    2. associate-/r/83.6%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{1}{F} \cdot \tan \left(\pi \cdot \ell\right)}}{-F}\right) \]
  6. Applied egg-rr83.6%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{1}{F} \cdot \tan \left(\pi \cdot \ell\right)}}{-F}\right) \]
  7. Final simplification83.6%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\frac{1}{F} \cdot \tan \left(\pi \cdot \ell\right)}{-F}\right) \]
  8. Add Preprocessing

Alternative 3: 82.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right) \end{array} \]
(FPCore (F l) :precision binary64 (fma PI l (/ (/ (tan (* PI l)) F) (- F))))
double code(double F, double l) {
	return fma(((double) M_PI), l, ((tan((((double) M_PI) * l)) / F) / -F));
}
function code(F, l)
	return fma(pi, l, Float64(Float64(tan(Float64(pi * l)) / F) / Float64(-F)))
end
code[F_, l_] := N[(Pi * l + N[(N[(N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision] / F), $MachinePrecision] / (-F)), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)
\end{array}
Derivation
  1. Initial program 76.7%

    \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
  2. Step-by-step derivation
    1. fma-neg76.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, -\frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\right)} \]
    2. distribute-lft-neg-in76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\left(-\frac{1}{F \cdot F}\right) \cdot \tan \left(\pi \cdot \ell\right)}\right) \]
    3. sqr-neg76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \left(-\frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}}\right) \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    4. distribute-neg-frac76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{-1}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    5. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{-1}}{\left(-F\right) \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    6. distribute-lft-neg-out76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    7. neg-mul-176.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-1 \cdot \left(F \cdot \left(-F\right)\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    8. associate-/r*76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{-1}{-1}}{F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    9. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{1}}{F \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    10. associate-*l/77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{F \cdot \left(-F\right)}}\right) \]
    11. *-lft-identity77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{F \cdot \left(-F\right)}\right) \]
    12. associate-/r*83.6%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}}\right) \]
  3. Simplified83.6%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)} \]
  4. Add Preprocessing
  5. Final simplification83.6%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right) \]
  6. Add Preprocessing

Alternative 4: 79.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq 4 \cdot 10^{-68}:\\ \;\;\;\;\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell - \tan \left(\pi \cdot \ell\right) \cdot \frac{1}{F \cdot F}\\ \end{array} \end{array} \]
(FPCore (F l)
 :precision binary64
 (if (<= (* PI l) 4e-68)
   (fma PI l (/ (* PI (/ l F)) (- F)))
   (- (* PI l) (* (tan (* PI l)) (/ 1.0 (* F F))))))
double code(double F, double l) {
	double tmp;
	if ((((double) M_PI) * l) <= 4e-68) {
		tmp = fma(((double) M_PI), l, ((((double) M_PI) * (l / F)) / -F));
	} else {
		tmp = (((double) M_PI) * l) - (tan((((double) M_PI) * l)) * (1.0 / (F * F)));
	}
	return tmp;
}
function code(F, l)
	tmp = 0.0
	if (Float64(pi * l) <= 4e-68)
		tmp = fma(pi, l, Float64(Float64(pi * Float64(l / F)) / Float64(-F)));
	else
		tmp = Float64(Float64(pi * l) - Float64(tan(Float64(pi * l)) * Float64(1.0 / Float64(F * F))));
	end
	return tmp
end
code[F_, l_] := If[LessEqual[N[(Pi * l), $MachinePrecision], 4e-68], N[(Pi * l + N[(N[(Pi * N[(l / F), $MachinePrecision]), $MachinePrecision] / (-F)), $MachinePrecision]), $MachinePrecision], N[(N[(Pi * l), $MachinePrecision] - N[(N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision] * N[(1.0 / N[(F * F), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\pi \cdot \ell \leq 4 \cdot 10^{-68}:\\
\;\;\;\;\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)\\

\mathbf{else}:\\
\;\;\;\;\pi \cdot \ell - \tan \left(\pi \cdot \ell\right) \cdot \frac{1}{F \cdot F}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 (PI.f64) l) < 4.00000000000000027e-68

    1. Initial program 76.8%

      \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
    2. Step-by-step derivation
      1. fma-neg76.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, -\frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\right)} \]
      2. distribute-lft-neg-in76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\left(-\frac{1}{F \cdot F}\right) \cdot \tan \left(\pi \cdot \ell\right)}\right) \]
      3. sqr-neg76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \left(-\frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}}\right) \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      4. distribute-neg-frac76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{-1}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      5. metadata-eval76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{-1}}{\left(-F\right) \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      6. distribute-lft-neg-out76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      7. neg-mul-176.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-1 \cdot \left(F \cdot \left(-F\right)\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      8. associate-/r*76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{-1}{-1}}{F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      9. metadata-eval76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{1}}{F \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      10. associate-*l/77.3%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{F \cdot \left(-F\right)}}\right) \]
      11. *-lft-identity77.3%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{F \cdot \left(-F\right)}\right) \]
      12. associate-/r*87.1%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}}\right) \]
    3. Simplified87.1%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in l around 0 83.4%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell \cdot \pi}{F}}}{-F}\right) \]
    6. Step-by-step derivation
      1. associate-/l*83.4%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{\frac{F}{\pi}}}}{-F}\right) \]
      2. associate-/r/83.4%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{F} \cdot \pi}}{-F}\right) \]
    7. Simplified83.4%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{F} \cdot \pi}}{-F}\right) \]

    if 4.00000000000000027e-68 < (*.f64 (PI.f64) l)

    1. Initial program 76.5%

      \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification81.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq 4 \cdot 10^{-68}:\\ \;\;\;\;\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell - \tan \left(\pi \cdot \ell\right) \cdot \frac{1}{F \cdot F}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 79.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq 4 \cdot 10^{-68}:\\ \;\;\;\;\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}\\ \end{array} \end{array} \]
(FPCore (F l)
 :precision binary64
 (if (<= (* PI l) 4e-68)
   (fma PI l (/ (* PI (/ l F)) (- F)))
   (- (* PI l) (/ (tan (* PI l)) (* F F)))))
double code(double F, double l) {
	double tmp;
	if ((((double) M_PI) * l) <= 4e-68) {
		tmp = fma(((double) M_PI), l, ((((double) M_PI) * (l / F)) / -F));
	} else {
		tmp = (((double) M_PI) * l) - (tan((((double) M_PI) * l)) / (F * F));
	}
	return tmp;
}
function code(F, l)
	tmp = 0.0
	if (Float64(pi * l) <= 4e-68)
		tmp = fma(pi, l, Float64(Float64(pi * Float64(l / F)) / Float64(-F)));
	else
		tmp = Float64(Float64(pi * l) - Float64(tan(Float64(pi * l)) / Float64(F * F)));
	end
	return tmp
end
code[F_, l_] := If[LessEqual[N[(Pi * l), $MachinePrecision], 4e-68], N[(Pi * l + N[(N[(Pi * N[(l / F), $MachinePrecision]), $MachinePrecision] / (-F)), $MachinePrecision]), $MachinePrecision], N[(N[(Pi * l), $MachinePrecision] - N[(N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision] / N[(F * F), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\pi \cdot \ell \leq 4 \cdot 10^{-68}:\\
\;\;\;\;\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)\\

\mathbf{else}:\\
\;\;\;\;\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 (PI.f64) l) < 4.00000000000000027e-68

    1. Initial program 76.8%

      \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
    2. Step-by-step derivation
      1. fma-neg76.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, -\frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\right)} \]
      2. distribute-lft-neg-in76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\left(-\frac{1}{F \cdot F}\right) \cdot \tan \left(\pi \cdot \ell\right)}\right) \]
      3. sqr-neg76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \left(-\frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}}\right) \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      4. distribute-neg-frac76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{-1}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      5. metadata-eval76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{-1}}{\left(-F\right) \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      6. distribute-lft-neg-out76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      7. neg-mul-176.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-1 \cdot \left(F \cdot \left(-F\right)\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      8. associate-/r*76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{-1}{-1}}{F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      9. metadata-eval76.8%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{1}}{F \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
      10. associate-*l/77.3%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{F \cdot \left(-F\right)}}\right) \]
      11. *-lft-identity77.3%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{F \cdot \left(-F\right)}\right) \]
      12. associate-/r*87.1%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}}\right) \]
    3. Simplified87.1%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in l around 0 83.4%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell \cdot \pi}{F}}}{-F}\right) \]
    6. Step-by-step derivation
      1. associate-/l*83.4%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{\frac{F}{\pi}}}}{-F}\right) \]
      2. associate-/r/83.4%

        \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{F} \cdot \pi}}{-F}\right) \]
    7. Simplified83.4%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{F} \cdot \pi}}{-F}\right) \]

    if 4.00000000000000027e-68 < (*.f64 (PI.f64) l)

    1. Initial program 76.5%

      \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
    2. Step-by-step derivation
      1. sqr-neg76.5%

        \[\leadsto \pi \cdot \ell - \frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right) \]
      2. associate-*l/76.5%

        \[\leadsto \pi \cdot \ell - \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{\left(-F\right) \cdot \left(-F\right)}} \]
      3. *-lft-identity76.5%

        \[\leadsto \pi \cdot \ell - \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{\left(-F\right) \cdot \left(-F\right)} \]
      4. sqr-neg76.5%

        \[\leadsto \pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{\color{blue}{F \cdot F}} \]
    3. Simplified76.5%

      \[\leadsto \color{blue}{\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}} \]
    4. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification81.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq 4 \cdot 10^{-68}:\\ \;\;\;\;\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 75.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right) \end{array} \]
(FPCore (F l) :precision binary64 (fma PI l (/ (* PI (/ l F)) (- F))))
double code(double F, double l) {
	return fma(((double) M_PI), l, ((((double) M_PI) * (l / F)) / -F));
}
function code(F, l)
	return fma(pi, l, Float64(Float64(pi * Float64(l / F)) / Float64(-F)))
end
code[F_, l_] := N[(Pi * l + N[(N[(Pi * N[(l / F), $MachinePrecision]), $MachinePrecision] / (-F)), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right)
\end{array}
Derivation
  1. Initial program 76.7%

    \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
  2. Step-by-step derivation
    1. fma-neg76.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, -\frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right)\right)} \]
    2. distribute-lft-neg-in76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\left(-\frac{1}{F \cdot F}\right) \cdot \tan \left(\pi \cdot \ell\right)}\right) \]
    3. sqr-neg76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \left(-\frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}}\right) \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    4. distribute-neg-frac76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{-1}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    5. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{-1}}{\left(-F\right) \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    6. distribute-lft-neg-out76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    7. neg-mul-176.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{-1}{\color{blue}{-1 \cdot \left(F \cdot \left(-F\right)\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    8. associate-/r*76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{-1}{-1}}{F \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    9. metadata-eval76.7%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{1}}{F \cdot \left(-F\right)} \cdot \tan \left(\pi \cdot \ell\right)\right) \]
    10. associate-*l/77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{F \cdot \left(-F\right)}}\right) \]
    11. *-lft-identity77.1%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{F \cdot \left(-F\right)}\right) \]
    12. associate-/r*83.6%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}}\right) \]
  3. Simplified83.6%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, \ell, \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{-F}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in l around 0 74.9%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell \cdot \pi}{F}}}{-F}\right) \]
  6. Step-by-step derivation
    1. associate-/l*74.9%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{\frac{F}{\pi}}}}{-F}\right) \]
    2. associate-/r/74.9%

      \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{F} \cdot \pi}}{-F}\right) \]
  7. Simplified74.9%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\color{blue}{\frac{\ell}{F} \cdot \pi}}{-F}\right) \]
  8. Final simplification74.9%

    \[\leadsto \mathsf{fma}\left(\pi, \ell, \frac{\pi \cdot \frac{\ell}{F}}{-F}\right) \]
  9. Add Preprocessing

Alternative 7: 70.1% accurate, 10.3× speedup?

\[\begin{array}{l} \\ \pi \cdot \ell - \frac{\pi \cdot \ell}{F \cdot F} \end{array} \]
(FPCore (F l) :precision binary64 (- (* PI l) (/ (* PI l) (* F F))))
double code(double F, double l) {
	return (((double) M_PI) * l) - ((((double) M_PI) * l) / (F * F));
}
public static double code(double F, double l) {
	return (Math.PI * l) - ((Math.PI * l) / (F * F));
}
def code(F, l):
	return (math.pi * l) - ((math.pi * l) / (F * F))
function code(F, l)
	return Float64(Float64(pi * l) - Float64(Float64(pi * l) / Float64(F * F)))
end
function tmp = code(F, l)
	tmp = (pi * l) - ((pi * l) / (F * F));
end
code[F_, l_] := N[(N[(Pi * l), $MachinePrecision] - N[(N[(Pi * l), $MachinePrecision] / N[(F * F), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\pi \cdot \ell - \frac{\pi \cdot \ell}{F \cdot F}
\end{array}
Derivation
  1. Initial program 76.7%

    \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]
  2. Step-by-step derivation
    1. sqr-neg76.7%

      \[\leadsto \pi \cdot \ell - \frac{1}{\color{blue}{\left(-F\right) \cdot \left(-F\right)}} \cdot \tan \left(\pi \cdot \ell\right) \]
    2. associate-*l/77.1%

      \[\leadsto \pi \cdot \ell - \color{blue}{\frac{1 \cdot \tan \left(\pi \cdot \ell\right)}{\left(-F\right) \cdot \left(-F\right)}} \]
    3. *-lft-identity77.1%

      \[\leadsto \pi \cdot \ell - \frac{\color{blue}{\tan \left(\pi \cdot \ell\right)}}{\left(-F\right) \cdot \left(-F\right)} \]
    4. sqr-neg77.1%

      \[\leadsto \pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{\color{blue}{F \cdot F}} \]
  3. Simplified77.1%

    \[\leadsto \color{blue}{\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}} \]
  4. Add Preprocessing
  5. Taylor expanded in l around 0 68.3%

    \[\leadsto \pi \cdot \ell - \frac{\color{blue}{\ell \cdot \pi}}{F \cdot F} \]
  6. Final simplification68.3%

    \[\leadsto \pi \cdot \ell - \frac{\pi \cdot \ell}{F \cdot F} \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024039 
(FPCore (F l)
  :name "VandenBroeck and Keller, Equation (6)"
  :precision binary64
  (- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))