Kahan p13 Example 2

Percentage Accurate: 100.0% → 100.0%
Time: 8.9s
Alternatives: 11
Speedup: 2.0×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\\ t_2 := t\_1 \cdot t\_1\\ \frac{1 + t\_2}{2 + t\_2} \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t))))) (t_2 (* t_1 t_1)))
   (/ (+ 1.0 t_2) (+ 2.0 t_2))))
double code(double t) {
	double t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)));
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: t_2
    t_1 = 2.0d0 - ((2.0d0 / t) / (1.0d0 + (1.0d0 / t)))
    t_2 = t_1 * t_1
    code = (1.0d0 + t_2) / (2.0d0 + t_2)
end function
public static double code(double t) {
	double t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)));
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
def code(t):
	t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)))
	t_2 = t_1 * t_1
	return (1.0 + t_2) / (2.0 + t_2)
function code(t)
	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + Float64(1.0 / t))))
	t_2 = Float64(t_1 * t_1)
	return Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2))
end
function tmp = code(t)
	t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)));
	t_2 = t_1 * t_1;
	tmp = (1.0 + t_2) / (2.0 + t_2);
end
code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[(1.0 / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\\
t_2 := t\_1 \cdot t\_1\\
\frac{1 + t\_2}{2 + t\_2}
\end{array}
\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 11 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: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\\ t_2 := t\_1 \cdot t\_1\\ \frac{1 + t\_2}{2 + t\_2} \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t))))) (t_2 (* t_1 t_1)))
   (/ (+ 1.0 t_2) (+ 2.0 t_2))))
double code(double t) {
	double t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)));
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: t_2
    t_1 = 2.0d0 - ((2.0d0 / t) / (1.0d0 + (1.0d0 / t)))
    t_2 = t_1 * t_1
    code = (1.0d0 + t_2) / (2.0d0 + t_2)
end function
public static double code(double t) {
	double t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)));
	double t_2 = t_1 * t_1;
	return (1.0 + t_2) / (2.0 + t_2);
}
def code(t):
	t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)))
	t_2 = t_1 * t_1
	return (1.0 + t_2) / (2.0 + t_2)
function code(t)
	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + Float64(1.0 / t))))
	t_2 = Float64(t_1 * t_1)
	return Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2))
end
function tmp = code(t)
	t_1 = 2.0 - ((2.0 / t) / (1.0 + (1.0 / t)));
	t_2 = t_1 * t_1;
	tmp = (1.0 + t_2) / (2.0 + t_2);
end
code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[(1.0 / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\\
t_2 := t\_1 \cdot t\_1\\
\frac{1 + t\_2}{2 + t\_2}
\end{array}
\end{array}

Alternative 1: 100.0% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{2}{1 + t} - 2\\ t_2 := 2 + \frac{-2}{1 + t}\\ \frac{\mathsf{fma}\left(t\_1, t\_1, 1\right)}{\frac{{t\_2}^{4} - 4}{{t\_2}^{2} - 2}} \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (- (/ 2.0 (+ 1.0 t)) 2.0)) (t_2 (+ 2.0 (/ -2.0 (+ 1.0 t)))))
   (/ (fma t_1 t_1 1.0) (/ (- (pow t_2 4.0) 4.0) (- (pow t_2 2.0) 2.0)))))
double code(double t) {
	double t_1 = (2.0 / (1.0 + t)) - 2.0;
	double t_2 = 2.0 + (-2.0 / (1.0 + t));
	return fma(t_1, t_1, 1.0) / ((pow(t_2, 4.0) - 4.0) / (pow(t_2, 2.0) - 2.0));
}
function code(t)
	t_1 = Float64(Float64(2.0 / Float64(1.0 + t)) - 2.0)
	t_2 = Float64(2.0 + Float64(-2.0 / Float64(1.0 + t)))
	return Float64(fma(t_1, t_1, 1.0) / Float64(Float64((t_2 ^ 4.0) - 4.0) / Float64((t_2 ^ 2.0) - 2.0)))
end
code[t_] := Block[{t$95$1 = N[(N[(2.0 / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] - 2.0), $MachinePrecision]}, Block[{t$95$2 = N[(2.0 + N[(-2.0 / N[(1.0 + t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(t$95$1 * t$95$1 + 1.0), $MachinePrecision] / N[(N[(N[Power[t$95$2, 4.0], $MachinePrecision] - 4.0), $MachinePrecision] / N[(N[Power[t$95$2, 2.0], $MachinePrecision] - 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{2}{1 + t} - 2\\
t_2 := 2 + \frac{-2}{1 + t}\\
\frac{\mathsf{fma}\left(t\_1, t\_1, 1\right)}{\frac{{t\_2}^{4} - 4}{{t\_2}^{2} - 2}}
\end{array}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-+.f64N/A

      \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}} \]
    2. +-commutativeN/A

      \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) + 2}} \]
    3. flip-+N/A

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

      \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{\frac{\left(\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)\right) \cdot \left(\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)\right) - 2 \cdot 2}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) - 2}}} \]
  4. Applied rewrites100.0%

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

      \[\leadsto \frac{\color{blue}{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    2. +-commutativeN/A

      \[\leadsto \frac{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) + 1}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    3. lift-*.f64N/A

      \[\leadsto \frac{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    4. sqr-abs-revN/A

      \[\leadsto \frac{\color{blue}{\left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right|} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    5. lift--.f64N/A

      \[\leadsto \frac{\left|\color{blue}{2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}}\right| \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    6. fabs-subN/A

      \[\leadsto \frac{\color{blue}{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right|} \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    7. lift--.f64N/A

      \[\leadsto \frac{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right| \cdot \left|\color{blue}{2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    8. fabs-subN/A

      \[\leadsto \frac{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right| \cdot \color{blue}{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right|} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    9. sqr-absN/A

      \[\leadsto \frac{\color{blue}{\left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right) \cdot \left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right)} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    10. lower-fma.f64N/A

      \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2, \frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2, 1\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
  6. Applied rewrites100.0%

    \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
  7. Add Preprocessing

Alternative 2: 99.4% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{2}{1 + t} - 2\\ t_2 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_3 := t\_2 \cdot t\_2\\ \mathbf{if}\;\frac{1 + t\_3}{2 + t\_3} \leq 0.6:\\ \;\;\;\;\frac{\mathsf{fma}\left(t\_1, t\_1, 1\right)}{2 + \left(\mathsf{fma}\left(\mathsf{fma}\left(-16, t, 12\right) \cdot t - 8, t, 4\right) \cdot t\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;\left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \frac{\frac{0.037037037037037035}{t}}{t}\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (- (/ 2.0 (+ 1.0 t)) 2.0))
        (t_2 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0)))))
        (t_3 (* t_2 t_2)))
   (if (<= (/ (+ 1.0 t_3) (+ 2.0 t_3)) 0.6)
     (/
      (fma t_1 t_1 1.0)
      (+ 2.0 (* (* (fma (- (* (fma -16.0 t 12.0) t) 8.0) t 4.0) t) t)))
     (+
      (- 0.8333333333333334 (/ 0.2222222222222222 t))
      (/ (/ 0.037037037037037035 t) t)))))
double code(double t) {
	double t_1 = (2.0 / (1.0 + t)) - 2.0;
	double t_2 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
	double t_3 = t_2 * t_2;
	double tmp;
	if (((1.0 + t_3) / (2.0 + t_3)) <= 0.6) {
		tmp = fma(t_1, t_1, 1.0) / (2.0 + ((fma(((fma(-16.0, t, 12.0) * t) - 8.0), t, 4.0) * t) * t));
	} else {
		tmp = (0.8333333333333334 - (0.2222222222222222 / t)) + ((0.037037037037037035 / t) / t);
	}
	return tmp;
}
function code(t)
	t_1 = Float64(Float64(2.0 / Float64(1.0 + t)) - 2.0)
	t_2 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
	t_3 = Float64(t_2 * t_2)
	tmp = 0.0
	if (Float64(Float64(1.0 + t_3) / Float64(2.0 + t_3)) <= 0.6)
		tmp = Float64(fma(t_1, t_1, 1.0) / Float64(2.0 + Float64(Float64(fma(Float64(Float64(fma(-16.0, t, 12.0) * t) - 8.0), t, 4.0) * t) * t)));
	else
		tmp = Float64(Float64(0.8333333333333334 - Float64(0.2222222222222222 / t)) + Float64(Float64(0.037037037037037035 / t) / t));
	end
	return tmp
end
code[t_] := Block[{t$95$1 = N[(N[(2.0 / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] - 2.0), $MachinePrecision]}, Block[{t$95$2 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$3 = N[(t$95$2 * t$95$2), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$3), $MachinePrecision] / N[(2.0 + t$95$3), $MachinePrecision]), $MachinePrecision], 0.6], N[(N[(t$95$1 * t$95$1 + 1.0), $MachinePrecision] / N[(2.0 + N[(N[(N[(N[(N[(N[(-16.0 * t + 12.0), $MachinePrecision] * t), $MachinePrecision] - 8.0), $MachinePrecision] * t + 4.0), $MachinePrecision] * t), $MachinePrecision] * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(0.8333333333333334 - N[(0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision] + N[(N[(0.037037037037037035 / t), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{2}{1 + t} - 2\\
t_2 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
t_3 := t\_2 \cdot t\_2\\
\mathbf{if}\;\frac{1 + t\_3}{2 + t\_3} \leq 0.6:\\
\;\;\;\;\frac{\mathsf{fma}\left(t\_1, t\_1, 1\right)}{2 + \left(\mathsf{fma}\left(\mathsf{fma}\left(-16, t, 12\right) \cdot t - 8, t, 4\right) \cdot t\right) \cdot t}\\

\mathbf{else}:\\
\;\;\;\;\left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \frac{\frac{0.037037037037037035}{t}}{t}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

    1. Initial program 100.0%

      \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Add Preprocessing
    3. Applied rewrites100.0%

      \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    4. Taylor expanded in t around 0

      \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \color{blue}{{t}^{2} \cdot \left(4 + t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right)\right)}} \]
    5. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \color{blue}{\left(4 + t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right)\right) \cdot {t}^{2}}} \]
      2. unpow2N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(4 + t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right)\right) \cdot \color{blue}{\left(t \cdot t\right)}} \]
      3. associate-*r*N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \color{blue}{\left(\left(4 + t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right)\right) \cdot t\right) \cdot t}} \]
      4. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \color{blue}{\left(\left(4 + t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right)\right) \cdot t\right) \cdot t}} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \color{blue}{\left(\left(4 + t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right)\right) \cdot t\right)} \cdot t} \]
      6. +-commutativeN/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\color{blue}{\left(t \cdot \left(t \cdot \left(12 + -16 \cdot t\right) - 8\right) + 4\right)} \cdot t\right) \cdot t} \]
      7. *-commutativeN/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\left(\color{blue}{\left(t \cdot \left(12 + -16 \cdot t\right) - 8\right) \cdot t} + 4\right) \cdot t\right) \cdot t} \]
      8. lower-fma.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\color{blue}{\mathsf{fma}\left(t \cdot \left(12 + -16 \cdot t\right) - 8, t, 4\right)} \cdot t\right) \cdot t} \]
      9. lower--.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\mathsf{fma}\left(\color{blue}{t \cdot \left(12 + -16 \cdot t\right) - 8}, t, 4\right) \cdot t\right) \cdot t} \]
      10. *-commutativeN/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\mathsf{fma}\left(\color{blue}{\left(12 + -16 \cdot t\right) \cdot t} - 8, t, 4\right) \cdot t\right) \cdot t} \]
      11. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\mathsf{fma}\left(\color{blue}{\left(12 + -16 \cdot t\right) \cdot t} - 8, t, 4\right) \cdot t\right) \cdot t} \]
      12. +-commutativeN/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\mathsf{fma}\left(\color{blue}{\left(-16 \cdot t + 12\right)} \cdot t - 8, t, 4\right) \cdot t\right) \cdot t} \]
      13. lower-fma.f6499.5

        \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-16, t, 12\right)} \cdot t - 8, t, 4\right) \cdot t\right) \cdot t} \]
    6. Applied rewrites99.5%

      \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \color{blue}{\left(\mathsf{fma}\left(\mathsf{fma}\left(-16, t, 12\right) \cdot t - 8, t, 4\right) \cdot t\right) \cdot t}} \]

    if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

    1. Initial program 100.0%

      \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-+.f64N/A

        \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}} \]
      2. +-commutativeN/A

        \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) + 2}} \]
      3. flip-+N/A

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

        \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{\frac{\left(\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)\right) \cdot \left(\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)\right) - 2 \cdot 2}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) - 2}}} \]
    4. Applied rewrites100.0%

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

        \[\leadsto \frac{\color{blue}{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      2. +-commutativeN/A

        \[\leadsto \frac{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) + 1}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      3. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      4. sqr-abs-revN/A

        \[\leadsto \frac{\color{blue}{\left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right|} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      5. lift--.f64N/A

        \[\leadsto \frac{\left|\color{blue}{2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}}\right| \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      6. fabs-subN/A

        \[\leadsto \frac{\color{blue}{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right|} \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      7. lift--.f64N/A

        \[\leadsto \frac{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right| \cdot \left|\color{blue}{2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      8. fabs-subN/A

        \[\leadsto \frac{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right| \cdot \color{blue}{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right|} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      9. sqr-absN/A

        \[\leadsto \frac{\color{blue}{\left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right) \cdot \left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right)} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      10. lower-fma.f64N/A

        \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2, \frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2, 1\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    6. Applied rewrites100.0%

      \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
    7. Taylor expanded in t around inf

      \[\leadsto \color{blue}{\left(\frac{5}{6} + \frac{\frac{1}{27}}{{t}^{2}}\right) - \frac{2}{9} \cdot \frac{1}{t}} \]
    8. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{\frac{1}{27}}{{t}^{2}} + \frac{5}{6}\right)} - \frac{2}{9} \cdot \frac{1}{t} \]
      2. associate--l+N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{27}}{{t}^{2}} + \left(\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}\right)} \]
      3. +-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}\right) + \frac{\frac{1}{27}}{{t}^{2}}} \]
      4. associate--r-N/A

        \[\leadsto \color{blue}{\frac{5}{6} - \left(\frac{2}{9} \cdot \frac{1}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)} \]
      5. associate-*r/N/A

        \[\leadsto \frac{5}{6} - \left(\color{blue}{\frac{\frac{2}{9} \cdot 1}{t}} - \frac{\frac{1}{27}}{{t}^{2}}\right) \]
      6. metadata-evalN/A

        \[\leadsto \frac{5}{6} - \left(\frac{\color{blue}{\frac{2}{9}}}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right) \]
      7. unpow2N/A

        \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{\color{blue}{t \cdot t}}\right) \]
      8. associate-/r*N/A

        \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \color{blue}{\frac{\frac{\frac{1}{27}}{t}}{t}}\right) \]
      9. metadata-evalN/A

        \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\color{blue}{\frac{1}{27} \cdot 1}}{t}}{t}\right) \]
      10. associate-*r/N/A

        \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\color{blue}{\frac{1}{27} \cdot \frac{1}{t}}}{t}\right) \]
      11. div-subN/A

        \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
      12. *-lft-identityN/A

        \[\leadsto \frac{5}{6} - \color{blue}{1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
      13. metadata-evalN/A

        \[\leadsto \frac{5}{6} - \color{blue}{\left(\mathsf{neg}\left(-1\right)\right)} \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \]
      14. fp-cancel-sign-sub-invN/A

        \[\leadsto \color{blue}{\frac{5}{6} + -1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
      15. *-commutativeN/A

        \[\leadsto \frac{5}{6} + \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot -1} \]
      16. fp-cancel-sign-sub-invN/A

        \[\leadsto \color{blue}{\frac{5}{6} - \left(\mathsf{neg}\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right) \cdot -1} \]
      17. mul-1-negN/A

        \[\leadsto \frac{5}{6} - \color{blue}{\left(-1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)} \cdot -1 \]
      18. *-commutativeN/A

        \[\leadsto \frac{5}{6} - \color{blue}{\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot -1\right)} \cdot -1 \]
      19. associate-*l*N/A

        \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot \left(-1 \cdot -1\right)} \]
    9. Applied rewrites99.4%

      \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035}{t}}{t}} \]
    10. Step-by-step derivation
      1. Applied rewrites99.5%

        \[\leadsto \left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \color{blue}{\frac{\frac{0.037037037037037035}{t}}{t}} \]
    11. Recombined 2 regimes into one program.
    12. Final simplification99.5%

      \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{2 + \left(\mathsf{fma}\left(\mathsf{fma}\left(-16, t, 12\right) \cdot t - 8, t, 4\right) \cdot t\right) \cdot t}\\ \mathbf{else}:\\ \;\;\;\;\left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \frac{\frac{0.037037037037037035}{t}}{t}\\ \end{array} \]
    13. Add Preprocessing

    Alternative 3: 99.4% accurate, 0.3× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \frac{\frac{0.037037037037037035}{t}}{t}\\ \end{array} \end{array} \]
    (FPCore (t)
     :precision binary64
     (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
       (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.6)
         (fma (fma (- t 2.0) t 1.0) (* t t) 0.5)
         (+
          (- 0.8333333333333334 (/ 0.2222222222222222 t))
          (/ (/ 0.037037037037037035 t) t)))))
    double code(double t) {
    	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
    	double t_2 = t_1 * t_1;
    	double tmp;
    	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.6) {
    		tmp = fma(fma((t - 2.0), t, 1.0), (t * t), 0.5);
    	} else {
    		tmp = (0.8333333333333334 - (0.2222222222222222 / t)) + ((0.037037037037037035 / t) / t);
    	}
    	return tmp;
    }
    
    function code(t)
    	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
    	t_2 = Float64(t_1 * t_1)
    	tmp = 0.0
    	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.6)
    		tmp = fma(fma(Float64(t - 2.0), t, 1.0), Float64(t * t), 0.5);
    	else
    		tmp = Float64(Float64(0.8333333333333334 - Float64(0.2222222222222222 / t)) + Float64(Float64(0.037037037037037035 / t) / t));
    	end
    	return tmp
    end
    
    code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.6], N[(N[(N[(t - 2.0), $MachinePrecision] * t + 1.0), $MachinePrecision] * N[(t * t), $MachinePrecision] + 0.5), $MachinePrecision], N[(N[(0.8333333333333334 - N[(0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision] + N[(N[(0.037037037037037035 / t), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
    t_2 := t\_1 \cdot t\_1\\
    \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\
    \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \frac{\frac{0.037037037037037035}{t}}{t}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

      1. Initial program 100.0%

        \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
      2. Add Preprocessing
      3. Taylor expanded in t around 0

        \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2} \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
      4. Step-by-step derivation
        1. fp-cancel-sign-sub-invN/A

          \[\leadsto \color{blue}{\frac{1}{2} - \left(\mathsf{neg}\left({t}^{2}\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
        2. fp-cancel-sub-sign-invN/A

          \[\leadsto \color{blue}{\frac{1}{2} + \left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
        3. +-commutativeN/A

          \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2}} \]
        4. remove-double-negN/A

          \[\leadsto \color{blue}{{t}^{2}} \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2} \]
        5. *-commutativeN/A

          \[\leadsto \color{blue}{\left(1 + t \cdot \left(t - 2\right)\right) \cdot {t}^{2}} + \frac{1}{2} \]
        6. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(1 + t \cdot \left(t - 2\right), {t}^{2}, \frac{1}{2}\right)} \]
        7. +-commutativeN/A

          \[\leadsto \mathsf{fma}\left(\color{blue}{t \cdot \left(t - 2\right) + 1}, {t}^{2}, \frac{1}{2}\right) \]
        8. *-commutativeN/A

          \[\leadsto \mathsf{fma}\left(\color{blue}{\left(t - 2\right) \cdot t} + 1, {t}^{2}, \frac{1}{2}\right) \]
        9. lower-fma.f64N/A

          \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(t - 2, t, 1\right)}, {t}^{2}, \frac{1}{2}\right) \]
        10. lower--.f64N/A

          \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{t - 2}, t, 1\right), {t}^{2}, \frac{1}{2}\right) \]
        11. unpow2N/A

          \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, \frac{1}{2}\right) \]
        12. lower-*.f6499.5

          \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, 0.5\right) \]
      5. Applied rewrites99.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)} \]

      if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

      1. Initial program 100.0%

        \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift-+.f64N/A

          \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}} \]
        2. +-commutativeN/A

          \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) + 2}} \]
        3. flip-+N/A

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

          \[\leadsto \frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{\color{blue}{\frac{\left(\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)\right) \cdot \left(\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)\right) - 2 \cdot 2}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) - 2}}} \]
      4. Applied rewrites100.0%

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

          \[\leadsto \frac{\color{blue}{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        2. +-commutativeN/A

          \[\leadsto \frac{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) + 1}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        3. lift-*.f64N/A

          \[\leadsto \frac{\color{blue}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        4. sqr-abs-revN/A

          \[\leadsto \frac{\color{blue}{\left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right|} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        5. lift--.f64N/A

          \[\leadsto \frac{\left|\color{blue}{2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}}\right| \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        6. fabs-subN/A

          \[\leadsto \frac{\color{blue}{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right|} \cdot \left|2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        7. lift--.f64N/A

          \[\leadsto \frac{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right| \cdot \left|\color{blue}{2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}}\right| + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        8. fabs-subN/A

          \[\leadsto \frac{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right| \cdot \color{blue}{\left|\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right|} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        9. sqr-absN/A

          \[\leadsto \frac{\color{blue}{\left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right) \cdot \left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right)} + 1}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
        10. lower-fma.f64N/A

          \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2, \frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2, 1\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      6. Applied rewrites100.0%

        \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}}{\frac{{\left(2 + \frac{-2}{1 + t}\right)}^{4} - 4}{{\left(2 + \frac{-2}{1 + t}\right)}^{2} - 2}} \]
      7. Taylor expanded in t around inf

        \[\leadsto \color{blue}{\left(\frac{5}{6} + \frac{\frac{1}{27}}{{t}^{2}}\right) - \frac{2}{9} \cdot \frac{1}{t}} \]
      8. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto \color{blue}{\left(\frac{\frac{1}{27}}{{t}^{2}} + \frac{5}{6}\right)} - \frac{2}{9} \cdot \frac{1}{t} \]
        2. associate--l+N/A

          \[\leadsto \color{blue}{\frac{\frac{1}{27}}{{t}^{2}} + \left(\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}\right)} \]
        3. +-commutativeN/A

          \[\leadsto \color{blue}{\left(\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}\right) + \frac{\frac{1}{27}}{{t}^{2}}} \]
        4. associate--r-N/A

          \[\leadsto \color{blue}{\frac{5}{6} - \left(\frac{2}{9} \cdot \frac{1}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)} \]
        5. associate-*r/N/A

          \[\leadsto \frac{5}{6} - \left(\color{blue}{\frac{\frac{2}{9} \cdot 1}{t}} - \frac{\frac{1}{27}}{{t}^{2}}\right) \]
        6. metadata-evalN/A

          \[\leadsto \frac{5}{6} - \left(\frac{\color{blue}{\frac{2}{9}}}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right) \]
        7. unpow2N/A

          \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{\color{blue}{t \cdot t}}\right) \]
        8. associate-/r*N/A

          \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \color{blue}{\frac{\frac{\frac{1}{27}}{t}}{t}}\right) \]
        9. metadata-evalN/A

          \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\color{blue}{\frac{1}{27} \cdot 1}}{t}}{t}\right) \]
        10. associate-*r/N/A

          \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\color{blue}{\frac{1}{27} \cdot \frac{1}{t}}}{t}\right) \]
        11. div-subN/A

          \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
        12. *-lft-identityN/A

          \[\leadsto \frac{5}{6} - \color{blue}{1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
        13. metadata-evalN/A

          \[\leadsto \frac{5}{6} - \color{blue}{\left(\mathsf{neg}\left(-1\right)\right)} \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \]
        14. fp-cancel-sign-sub-invN/A

          \[\leadsto \color{blue}{\frac{5}{6} + -1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
        15. *-commutativeN/A

          \[\leadsto \frac{5}{6} + \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot -1} \]
        16. fp-cancel-sign-sub-invN/A

          \[\leadsto \color{blue}{\frac{5}{6} - \left(\mathsf{neg}\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right) \cdot -1} \]
        17. mul-1-negN/A

          \[\leadsto \frac{5}{6} - \color{blue}{\left(-1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)} \cdot -1 \]
        18. *-commutativeN/A

          \[\leadsto \frac{5}{6} - \color{blue}{\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot -1\right)} \cdot -1 \]
        19. associate-*l*N/A

          \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot \left(-1 \cdot -1\right)} \]
      9. Applied rewrites99.4%

        \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035}{t}}{t}} \]
      10. Step-by-step derivation
        1. Applied rewrites99.5%

          \[\leadsto \left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \color{blue}{\frac{\frac{0.037037037037037035}{t}}{t}} \]
      11. Recombined 2 regimes into one program.
      12. Final simplification99.5%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\left(0.8333333333333334 - \frac{0.2222222222222222}{t}\right) + \frac{\frac{0.037037037037037035}{t}}{t}\\ \end{array} \]
      13. Add Preprocessing

      Alternative 4: 99.4% accurate, 0.3× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035}{t}}{t}\\ \end{array} \end{array} \]
      (FPCore (t)
       :precision binary64
       (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
         (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.6)
           (fma (fma (- t 2.0) t 1.0) (* t t) 0.5)
           (-
            0.8333333333333334
            (/ (- 0.2222222222222222 (/ 0.037037037037037035 t)) t)))))
      double code(double t) {
      	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
      	double t_2 = t_1 * t_1;
      	double tmp;
      	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.6) {
      		tmp = fma(fma((t - 2.0), t, 1.0), (t * t), 0.5);
      	} else {
      		tmp = 0.8333333333333334 - ((0.2222222222222222 - (0.037037037037037035 / t)) / t);
      	}
      	return tmp;
      }
      
      function code(t)
      	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
      	t_2 = Float64(t_1 * t_1)
      	tmp = 0.0
      	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.6)
      		tmp = fma(fma(Float64(t - 2.0), t, 1.0), Float64(t * t), 0.5);
      	else
      		tmp = Float64(0.8333333333333334 - Float64(Float64(0.2222222222222222 - Float64(0.037037037037037035 / t)) / t));
      	end
      	return tmp
      end
      
      code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.6], N[(N[(N[(t - 2.0), $MachinePrecision] * t + 1.0), $MachinePrecision] * N[(t * t), $MachinePrecision] + 0.5), $MachinePrecision], N[(0.8333333333333334 - N[(N[(0.2222222222222222 - N[(0.037037037037037035 / t), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
      t_2 := t\_1 \cdot t\_1\\
      \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\
      \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\
      
      \mathbf{else}:\\
      \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035}{t}}{t}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

        1. Initial program 100.0%

          \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in t around 0

          \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2} \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
        4. Step-by-step derivation
          1. fp-cancel-sign-sub-invN/A

            \[\leadsto \color{blue}{\frac{1}{2} - \left(\mathsf{neg}\left({t}^{2}\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
          2. fp-cancel-sub-sign-invN/A

            \[\leadsto \color{blue}{\frac{1}{2} + \left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
          3. +-commutativeN/A

            \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2}} \]
          4. remove-double-negN/A

            \[\leadsto \color{blue}{{t}^{2}} \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2} \]
          5. *-commutativeN/A

            \[\leadsto \color{blue}{\left(1 + t \cdot \left(t - 2\right)\right) \cdot {t}^{2}} + \frac{1}{2} \]
          6. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left(1 + t \cdot \left(t - 2\right), {t}^{2}, \frac{1}{2}\right)} \]
          7. +-commutativeN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{t \cdot \left(t - 2\right) + 1}, {t}^{2}, \frac{1}{2}\right) \]
          8. *-commutativeN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{\left(t - 2\right) \cdot t} + 1, {t}^{2}, \frac{1}{2}\right) \]
          9. lower-fma.f64N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(t - 2, t, 1\right)}, {t}^{2}, \frac{1}{2}\right) \]
          10. lower--.f64N/A

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{t - 2}, t, 1\right), {t}^{2}, \frac{1}{2}\right) \]
          11. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, \frac{1}{2}\right) \]
          12. lower-*.f6499.5

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, 0.5\right) \]
        5. Applied rewrites99.5%

          \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)} \]

        if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

        1. Initial program 100.0%

          \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in t around inf

          \[\leadsto \color{blue}{\left(\frac{5}{6} + \frac{\frac{1}{27}}{{t}^{2}}\right) - \frac{2}{9} \cdot \frac{1}{t}} \]
        4. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \color{blue}{\left(\frac{\frac{1}{27}}{{t}^{2}} + \frac{5}{6}\right)} - \frac{2}{9} \cdot \frac{1}{t} \]
          2. associate--l+N/A

            \[\leadsto \color{blue}{\frac{\frac{1}{27}}{{t}^{2}} + \left(\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}\right)} \]
          3. +-commutativeN/A

            \[\leadsto \color{blue}{\left(\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}\right) + \frac{\frac{1}{27}}{{t}^{2}}} \]
          4. associate--r-N/A

            \[\leadsto \color{blue}{\frac{5}{6} - \left(\frac{2}{9} \cdot \frac{1}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right)} \]
          5. associate-*r/N/A

            \[\leadsto \frac{5}{6} - \left(\color{blue}{\frac{\frac{2}{9} \cdot 1}{t}} - \frac{\frac{1}{27}}{{t}^{2}}\right) \]
          6. metadata-evalN/A

            \[\leadsto \frac{5}{6} - \left(\frac{\color{blue}{\frac{2}{9}}}{t} - \frac{\frac{1}{27}}{{t}^{2}}\right) \]
          7. unpow2N/A

            \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{1}{27}}{\color{blue}{t \cdot t}}\right) \]
          8. associate-/r*N/A

            \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \color{blue}{\frac{\frac{\frac{1}{27}}{t}}{t}}\right) \]
          9. metadata-evalN/A

            \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\frac{\color{blue}{\frac{1}{27} \cdot 1}}{t}}{t}\right) \]
          10. associate-*r/N/A

            \[\leadsto \frac{5}{6} - \left(\frac{\frac{2}{9}}{t} - \frac{\color{blue}{\frac{1}{27} \cdot \frac{1}{t}}}{t}\right) \]
          11. div-subN/A

            \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
          12. *-lft-identityN/A

            \[\leadsto \frac{5}{6} - \color{blue}{1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
          13. metadata-evalN/A

            \[\leadsto \frac{5}{6} - \color{blue}{\left(\mathsf{neg}\left(-1\right)\right)} \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \]
          14. fp-cancel-sign-sub-invN/A

            \[\leadsto \color{blue}{\frac{5}{6} + -1 \cdot \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
          15. *-commutativeN/A

            \[\leadsto \frac{5}{6} + \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot -1} \]
          16. fp-cancel-sign-sub-invN/A

            \[\leadsto \color{blue}{\frac{5}{6} - \left(\mathsf{neg}\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}\right)\right) \cdot -1} \]
          17. distribute-lft-neg-outN/A

            \[\leadsto \frac{5}{6} - \color{blue}{\left(\mathsf{neg}\left(\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot -1\right)\right)} \]
          18. distribute-rgt-neg-inN/A

            \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot \left(\mathsf{neg}\left(-1\right)\right)} \]
          19. metadata-evalN/A

            \[\leadsto \frac{5}{6} - \frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t} \cdot \color{blue}{1} \]
          20. *-rgt-identityN/A

            \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} - \frac{1}{27} \cdot \frac{1}{t}}{t}} \]
        5. Applied rewrites99.4%

          \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035}{t}}{t}} \]
      3. Recombined 2 regimes into one program.
      4. Final simplification99.5%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035}{t}}{t}\\ \end{array} \]
      5. Add Preprocessing

      Alternative 5: 99.2% accurate, 0.3× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\ \end{array} \end{array} \]
      (FPCore (t)
       :precision binary64
       (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
         (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.6)
           (fma (fma (- t 2.0) t 1.0) (* t t) 0.5)
           (- 0.8333333333333334 (/ 0.2222222222222222 t)))))
      double code(double t) {
      	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
      	double t_2 = t_1 * t_1;
      	double tmp;
      	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.6) {
      		tmp = fma(fma((t - 2.0), t, 1.0), (t * t), 0.5);
      	} else {
      		tmp = 0.8333333333333334 - (0.2222222222222222 / t);
      	}
      	return tmp;
      }
      
      function code(t)
      	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
      	t_2 = Float64(t_1 * t_1)
      	tmp = 0.0
      	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.6)
      		tmp = fma(fma(Float64(t - 2.0), t, 1.0), Float64(t * t), 0.5);
      	else
      		tmp = Float64(0.8333333333333334 - Float64(0.2222222222222222 / t));
      	end
      	return tmp
      end
      
      code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.6], N[(N[(N[(t - 2.0), $MachinePrecision] * t + 1.0), $MachinePrecision] * N[(t * t), $MachinePrecision] + 0.5), $MachinePrecision], N[(0.8333333333333334 - N[(0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
      t_2 := t\_1 \cdot t\_1\\
      \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\
      \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\
      
      \mathbf{else}:\\
      \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

        1. Initial program 100.0%

          \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in t around 0

          \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2} \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
        4. Step-by-step derivation
          1. fp-cancel-sign-sub-invN/A

            \[\leadsto \color{blue}{\frac{1}{2} - \left(\mathsf{neg}\left({t}^{2}\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
          2. fp-cancel-sub-sign-invN/A

            \[\leadsto \color{blue}{\frac{1}{2} + \left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
          3. +-commutativeN/A

            \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2}} \]
          4. remove-double-negN/A

            \[\leadsto \color{blue}{{t}^{2}} \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2} \]
          5. *-commutativeN/A

            \[\leadsto \color{blue}{\left(1 + t \cdot \left(t - 2\right)\right) \cdot {t}^{2}} + \frac{1}{2} \]
          6. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left(1 + t \cdot \left(t - 2\right), {t}^{2}, \frac{1}{2}\right)} \]
          7. +-commutativeN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{t \cdot \left(t - 2\right) + 1}, {t}^{2}, \frac{1}{2}\right) \]
          8. *-commutativeN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{\left(t - 2\right) \cdot t} + 1, {t}^{2}, \frac{1}{2}\right) \]
          9. lower-fma.f64N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(t - 2, t, 1\right)}, {t}^{2}, \frac{1}{2}\right) \]
          10. lower--.f64N/A

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{t - 2}, t, 1\right), {t}^{2}, \frac{1}{2}\right) \]
          11. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, \frac{1}{2}\right) \]
          12. lower-*.f6499.5

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, 0.5\right) \]
        5. Applied rewrites99.5%

          \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)} \]

        if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

        1. Initial program 100.0%

          \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in t around inf

          \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
        4. Step-by-step derivation
          1. lower--.f64N/A

            \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
          2. associate-*r/N/A

            \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} \cdot 1}{t}} \]
          3. metadata-evalN/A

            \[\leadsto \frac{5}{6} - \frac{\color{blue}{\frac{2}{9}}}{t} \]
          4. lower-/.f6499.3

            \[\leadsto 0.8333333333333334 - \color{blue}{\frac{0.2222222222222222}{t}} \]
        5. Applied rewrites99.3%

          \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222}{t}} \]
      3. Recombined 2 regimes into one program.
      4. Final simplification99.4%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\ \end{array} \]
      5. Add Preprocessing

      Alternative 6: 99.2% accurate, 0.3× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\ \end{array} \end{array} \]
      (FPCore (t)
       :precision binary64
       (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
         (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.6)
           (fma (fma -2.0 t 1.0) (* t t) 0.5)
           (- 0.8333333333333334 (/ 0.2222222222222222 t)))))
      double code(double t) {
      	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
      	double t_2 = t_1 * t_1;
      	double tmp;
      	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.6) {
      		tmp = fma(fma(-2.0, t, 1.0), (t * t), 0.5);
      	} else {
      		tmp = 0.8333333333333334 - (0.2222222222222222 / t);
      	}
      	return tmp;
      }
      
      function code(t)
      	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
      	t_2 = Float64(t_1 * t_1)
      	tmp = 0.0
      	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.6)
      		tmp = fma(fma(-2.0, t, 1.0), Float64(t * t), 0.5);
      	else
      		tmp = Float64(0.8333333333333334 - Float64(0.2222222222222222 / t));
      	end
      	return tmp
      end
      
      code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.6], N[(N[(-2.0 * t + 1.0), $MachinePrecision] * N[(t * t), $MachinePrecision] + 0.5), $MachinePrecision], N[(0.8333333333333334 - N[(0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
      t_2 := t\_1 \cdot t\_1\\
      \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\
      \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-2, t, 1\right), t \cdot t, 0.5\right)\\
      
      \mathbf{else}:\\
      \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

        1. Initial program 100.0%

          \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in t around 0

          \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2} \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
        4. Step-by-step derivation
          1. fp-cancel-sign-sub-invN/A

            \[\leadsto \color{blue}{\frac{1}{2} - \left(\mathsf{neg}\left({t}^{2}\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
          2. fp-cancel-sub-sign-invN/A

            \[\leadsto \color{blue}{\frac{1}{2} + \left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right)} \]
          3. +-commutativeN/A

            \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left({t}^{2}\right)\right)\right)\right) \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2}} \]
          4. remove-double-negN/A

            \[\leadsto \color{blue}{{t}^{2}} \cdot \left(1 + t \cdot \left(t - 2\right)\right) + \frac{1}{2} \]
          5. *-commutativeN/A

            \[\leadsto \color{blue}{\left(1 + t \cdot \left(t - 2\right)\right) \cdot {t}^{2}} + \frac{1}{2} \]
          6. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left(1 + t \cdot \left(t - 2\right), {t}^{2}, \frac{1}{2}\right)} \]
          7. +-commutativeN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{t \cdot \left(t - 2\right) + 1}, {t}^{2}, \frac{1}{2}\right) \]
          8. *-commutativeN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{\left(t - 2\right) \cdot t} + 1, {t}^{2}, \frac{1}{2}\right) \]
          9. lower-fma.f64N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(t - 2, t, 1\right)}, {t}^{2}, \frac{1}{2}\right) \]
          10. lower--.f64N/A

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{t - 2}, t, 1\right), {t}^{2}, \frac{1}{2}\right) \]
          11. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, \frac{1}{2}\right) \]
          12. lower-*.f6499.5

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), \color{blue}{t \cdot t}, 0.5\right) \]
        5. Applied rewrites99.5%

          \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(t - 2, t, 1\right), t \cdot t, 0.5\right)} \]
        6. Taylor expanded in t around 0

          \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(-2, t, 1\right), t \cdot t, \frac{1}{2}\right) \]
        7. Step-by-step derivation
          1. Applied rewrites99.4%

            \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(-2, t, 1\right), t \cdot t, 0.5\right) \]

          if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

          1. Initial program 100.0%

            \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in t around inf

            \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
          4. Step-by-step derivation
            1. lower--.f64N/A

              \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
            2. associate-*r/N/A

              \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} \cdot 1}{t}} \]
            3. metadata-evalN/A

              \[\leadsto \frac{5}{6} - \frac{\color{blue}{\frac{2}{9}}}{t} \]
            4. lower-/.f6499.3

              \[\leadsto 0.8333333333333334 - \color{blue}{\frac{0.2222222222222222}{t}} \]
          5. Applied rewrites99.3%

            \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222}{t}} \]
        8. Recombined 2 regimes into one program.
        9. Final simplification99.4%

          \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-2, t, 1\right), t \cdot t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\ \end{array} \]
        10. Add Preprocessing

        Alternative 7: 99.1% accurate, 0.3× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(t, t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\ \end{array} \end{array} \]
        (FPCore (t)
         :precision binary64
         (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
           (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.6)
             (fma t t 0.5)
             (- 0.8333333333333334 (/ 0.2222222222222222 t)))))
        double code(double t) {
        	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
        	double t_2 = t_1 * t_1;
        	double tmp;
        	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.6) {
        		tmp = fma(t, t, 0.5);
        	} else {
        		tmp = 0.8333333333333334 - (0.2222222222222222 / t);
        	}
        	return tmp;
        }
        
        function code(t)
        	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
        	t_2 = Float64(t_1 * t_1)
        	tmp = 0.0
        	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.6)
        		tmp = fma(t, t, 0.5);
        	else
        		tmp = Float64(0.8333333333333334 - Float64(0.2222222222222222 / t));
        	end
        	return tmp
        end
        
        code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.6], N[(t * t + 0.5), $MachinePrecision], N[(0.8333333333333334 - N[(0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision]]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
        t_2 := t\_1 \cdot t\_1\\
        \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\
        \;\;\;\;\mathsf{fma}\left(t, t, 0.5\right)\\
        
        \mathbf{else}:\\
        \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

          1. Initial program 100.0%

            \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in t around 0

            \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2}} \]
          4. Step-by-step derivation
            1. +-commutativeN/A

              \[\leadsto \color{blue}{{t}^{2} + \frac{1}{2}} \]
            2. unpow2N/A

              \[\leadsto \color{blue}{t \cdot t} + \frac{1}{2} \]
            3. lower-fma.f6498.8

              \[\leadsto \color{blue}{\mathsf{fma}\left(t, t, 0.5\right)} \]
          5. Applied rewrites98.8%

            \[\leadsto \color{blue}{\mathsf{fma}\left(t, t, 0.5\right)} \]

          if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

          1. Initial program 100.0%

            \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in t around inf

            \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
          4. Step-by-step derivation
            1. lower--.f64N/A

              \[\leadsto \color{blue}{\frac{5}{6} - \frac{2}{9} \cdot \frac{1}{t}} \]
            2. associate-*r/N/A

              \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} \cdot 1}{t}} \]
            3. metadata-evalN/A

              \[\leadsto \frac{5}{6} - \frac{\color{blue}{\frac{2}{9}}}{t} \]
            4. lower-/.f6499.3

              \[\leadsto 0.8333333333333334 - \color{blue}{\frac{0.2222222222222222}{t}} \]
          5. Applied rewrites99.3%

            \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222}{t}} \]
        3. Recombined 2 regimes into one program.
        4. Final simplification99.1%

          \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(t, t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 - \frac{0.2222222222222222}{t}\\ \end{array} \]
        5. Add Preprocessing

        Alternative 8: 98.5% accurate, 0.3× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(t, t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \end{array} \]
        (FPCore (t)
         :precision binary64
         (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
           (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.6) (fma t t 0.5) 0.8333333333333334)))
        double code(double t) {
        	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
        	double t_2 = t_1 * t_1;
        	double tmp;
        	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.6) {
        		tmp = fma(t, t, 0.5);
        	} else {
        		tmp = 0.8333333333333334;
        	}
        	return tmp;
        }
        
        function code(t)
        	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
        	t_2 = Float64(t_1 * t_1)
        	tmp = 0.0
        	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.6)
        		tmp = fma(t, t, 0.5);
        	else
        		tmp = 0.8333333333333334;
        	end
        	return tmp
        end
        
        code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.6], N[(t * t + 0.5), $MachinePrecision], 0.8333333333333334]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
        t_2 := t\_1 \cdot t\_1\\
        \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.6:\\
        \;\;\;\;\mathsf{fma}\left(t, t, 0.5\right)\\
        
        \mathbf{else}:\\
        \;\;\;\;0.8333333333333334\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.599999999999999978

          1. Initial program 100.0%

            \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in t around 0

            \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2}} \]
          4. Step-by-step derivation
            1. +-commutativeN/A

              \[\leadsto \color{blue}{{t}^{2} + \frac{1}{2}} \]
            2. unpow2N/A

              \[\leadsto \color{blue}{t \cdot t} + \frac{1}{2} \]
            3. lower-fma.f6498.8

              \[\leadsto \color{blue}{\mathsf{fma}\left(t, t, 0.5\right)} \]
          5. Applied rewrites98.8%

            \[\leadsto \color{blue}{\mathsf{fma}\left(t, t, 0.5\right)} \]

          if 0.599999999999999978 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

          1. Initial program 100.0%

            \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in t around inf

            \[\leadsto \color{blue}{\frac{5}{6}} \]
          4. Step-by-step derivation
            1. Applied rewrites99.0%

              \[\leadsto \color{blue}{0.8333333333333334} \]
          5. Recombined 2 regimes into one program.
          6. Final simplification98.9%

            \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.6:\\ \;\;\;\;\mathsf{fma}\left(t, t, 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \]
          7. Add Preprocessing

          Alternative 9: 98.4% accurate, 0.3× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\ t_2 := t\_1 \cdot t\_1\\ \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.65:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \end{array} \]
          (FPCore (t)
           :precision binary64
           (let* ((t_1 (- 2.0 (/ (/ 2.0 t) (+ 1.0 (pow t -1.0))))) (t_2 (* t_1 t_1)))
             (if (<= (/ (+ 1.0 t_2) (+ 2.0 t_2)) 0.65) 0.5 0.8333333333333334)))
          double code(double t) {
          	double t_1 = 2.0 - ((2.0 / t) / (1.0 + pow(t, -1.0)));
          	double t_2 = t_1 * t_1;
          	double tmp;
          	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.65) {
          		tmp = 0.5;
          	} else {
          		tmp = 0.8333333333333334;
          	}
          	return tmp;
          }
          
          real(8) function code(t)
              real(8), intent (in) :: t
              real(8) :: t_1
              real(8) :: t_2
              real(8) :: tmp
              t_1 = 2.0d0 - ((2.0d0 / t) / (1.0d0 + (t ** (-1.0d0))))
              t_2 = t_1 * t_1
              if (((1.0d0 + t_2) / (2.0d0 + t_2)) <= 0.65d0) then
                  tmp = 0.5d0
              else
                  tmp = 0.8333333333333334d0
              end if
              code = tmp
          end function
          
          public static double code(double t) {
          	double t_1 = 2.0 - ((2.0 / t) / (1.0 + Math.pow(t, -1.0)));
          	double t_2 = t_1 * t_1;
          	double tmp;
          	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.65) {
          		tmp = 0.5;
          	} else {
          		tmp = 0.8333333333333334;
          	}
          	return tmp;
          }
          
          def code(t):
          	t_1 = 2.0 - ((2.0 / t) / (1.0 + math.pow(t, -1.0)))
          	t_2 = t_1 * t_1
          	tmp = 0
          	if ((1.0 + t_2) / (2.0 + t_2)) <= 0.65:
          		tmp = 0.5
          	else:
          		tmp = 0.8333333333333334
          	return tmp
          
          function code(t)
          	t_1 = Float64(2.0 - Float64(Float64(2.0 / t) / Float64(1.0 + (t ^ -1.0))))
          	t_2 = Float64(t_1 * t_1)
          	tmp = 0.0
          	if (Float64(Float64(1.0 + t_2) / Float64(2.0 + t_2)) <= 0.65)
          		tmp = 0.5;
          	else
          		tmp = 0.8333333333333334;
          	end
          	return tmp
          end
          
          function tmp_2 = code(t)
          	t_1 = 2.0 - ((2.0 / t) / (1.0 + (t ^ -1.0)));
          	t_2 = t_1 * t_1;
          	tmp = 0.0;
          	if (((1.0 + t_2) / (2.0 + t_2)) <= 0.65)
          		tmp = 0.5;
          	else
          		tmp = 0.8333333333333334;
          	end
          	tmp_2 = tmp;
          end
          
          code[t_] := Block[{t$95$1 = N[(2.0 - N[(N[(2.0 / t), $MachinePrecision] / N[(1.0 + N[Power[t, -1.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(1.0 + t$95$2), $MachinePrecision] / N[(2.0 + t$95$2), $MachinePrecision]), $MachinePrecision], 0.65], 0.5, 0.8333333333333334]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_1 := 2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\\
          t_2 := t\_1 \cdot t\_1\\
          \mathbf{if}\;\frac{1 + t\_2}{2 + t\_2} \leq 0.65:\\
          \;\;\;\;0.5\\
          
          \mathbf{else}:\\
          \;\;\;\;0.8333333333333334\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t))))))) < 0.650000000000000022

            1. Initial program 100.0%

              \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
            2. Add Preprocessing
            3. Taylor expanded in t around 0

              \[\leadsto \color{blue}{\frac{1}{2}} \]
            4. Step-by-step derivation
              1. Applied rewrites98.1%

                \[\leadsto \color{blue}{0.5} \]

              if 0.650000000000000022 < (/.f64 (+.f64 #s(literal 1 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))) (+.f64 #s(literal 2 binary64) (*.f64 (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))) (-.f64 #s(literal 2 binary64) (/.f64 (/.f64 #s(literal 2 binary64) t) (+.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) t)))))))

              1. Initial program 100.0%

                \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
              2. Add Preprocessing
              3. Taylor expanded in t around inf

                \[\leadsto \color{blue}{\frac{5}{6}} \]
              4. Step-by-step derivation
                1. Applied rewrites99.0%

                  \[\leadsto \color{blue}{0.8333333333333334} \]
              5. Recombined 2 regimes into one program.
              6. Final simplification98.6%

                \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + {t}^{-1}}\right)} \leq 0.65:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \]
              7. Add Preprocessing

              Alternative 10: 100.0% accurate, 2.0× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{2}{1 + t} - 2\\ t_2 := \frac{2}{t + 1} - 2\\ \frac{\mathsf{fma}\left(t\_1, t\_1, 1\right)}{\mathsf{fma}\left(t\_2, t\_2, 2\right)} \end{array} \end{array} \]
              (FPCore (t)
               :precision binary64
               (let* ((t_1 (- (/ 2.0 (+ 1.0 t)) 2.0)) (t_2 (- (/ 2.0 (+ t 1.0)) 2.0)))
                 (/ (fma t_1 t_1 1.0) (fma t_2 t_2 2.0))))
              double code(double t) {
              	double t_1 = (2.0 / (1.0 + t)) - 2.0;
              	double t_2 = (2.0 / (t + 1.0)) - 2.0;
              	return fma(t_1, t_1, 1.0) / fma(t_2, t_2, 2.0);
              }
              
              function code(t)
              	t_1 = Float64(Float64(2.0 / Float64(1.0 + t)) - 2.0)
              	t_2 = Float64(Float64(2.0 / Float64(t + 1.0)) - 2.0)
              	return Float64(fma(t_1, t_1, 1.0) / fma(t_2, t_2, 2.0))
              end
              
              code[t_] := Block[{t$95$1 = N[(N[(2.0 / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] - 2.0), $MachinePrecision]}, Block[{t$95$2 = N[(N[(2.0 / N[(t + 1.0), $MachinePrecision]), $MachinePrecision] - 2.0), $MachinePrecision]}, N[(N[(t$95$1 * t$95$1 + 1.0), $MachinePrecision] / N[(t$95$2 * t$95$2 + 2.0), $MachinePrecision]), $MachinePrecision]]]
              
              \begin{array}{l}
              
              \\
              \begin{array}{l}
              t_1 := \frac{2}{1 + t} - 2\\
              t_2 := \frac{2}{t + 1} - 2\\
              \frac{\mathsf{fma}\left(t\_1, t\_1, 1\right)}{\mathsf{fma}\left(t\_2, t\_2, 2\right)}
              \end{array}
              \end{array}
              
              Derivation
              1. Initial program 100.0%

                \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
              2. Add Preprocessing
              3. Applied rewrites100.0%

                \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
              4. Applied rewrites100.0%

                \[\leadsto \frac{\mathsf{fma}\left(\frac{2}{1 + t} - 2, \frac{2}{1 + t} - 2, 1\right)}{\color{blue}{\mathsf{fma}\left(\frac{2}{t + 1} - 2, \frac{2}{t + 1} - 2, 2\right)}} \]
              5. Add Preprocessing

              Alternative 11: 58.6% accurate, 184.0× speedup?

              \[\begin{array}{l} \\ 0.5 \end{array} \]
              (FPCore (t) :precision binary64 0.5)
              double code(double t) {
              	return 0.5;
              }
              
              real(8) function code(t)
                  real(8), intent (in) :: t
                  code = 0.5d0
              end function
              
              public static double code(double t) {
              	return 0.5;
              }
              
              def code(t):
              	return 0.5
              
              function code(t)
              	return 0.5
              end
              
              function tmp = code(t)
              	tmp = 0.5;
              end
              
              code[t_] := 0.5
              
              \begin{array}{l}
              
              \\
              0.5
              \end{array}
              
              Derivation
              1. Initial program 100.0%

                \[\frac{1 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
              2. Add Preprocessing
              3. Taylor expanded in t around 0

                \[\leadsto \color{blue}{\frac{1}{2}} \]
              4. Step-by-step derivation
                1. Applied rewrites56.7%

                  \[\leadsto \color{blue}{0.5} \]
                2. Add Preprocessing

                Reproduce

                ?
                herbie shell --seed 2024344 
                (FPCore (t)
                  :name "Kahan p13 Example 2"
                  :precision binary64
                  (/ (+ 1.0 (* (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t)))) (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t)))))) (+ 2.0 (* (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t)))) (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t))))))))