Kahan p13 Example 3

Percentage Accurate: 100.0% → 100.0%
Time: 8.4s
Alternatives: 11
Speedup: 1.5×

Specification

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

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

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

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

Alternative 1: 100.0% accurate, 1.0× speedup?

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

\\
\begin{array}{l}
t_1 := \frac{\frac{2}{t}}{1 + \frac{1}{t}}\\
1 + \frac{1}{\left(2 - t\_1\right) \cdot \left(t\_1 - 2\right) - 2}
\end{array}
\end{array}
Derivation
  1. Initial program 100.0%

    \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
  2. Add Preprocessing
  3. Final simplification100.0%

    \[\leadsto 1 + \frac{1}{\left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(\frac{\frac{2}{t}}{1 + \frac{1}{t}} - 2\right) - 2} \]
  4. Add Preprocessing

Alternative 2: 99.4% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035 + \frac{0.04938271604938271}{t}}{t} - 0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -0.48:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.74:\\ \;\;\;\;0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1
         (+
          0.8333333333333334
          (/
           (-
            (/ (+ 0.037037037037037035 (/ 0.04938271604938271 t)) t)
            0.2222222222222222)
           t))))
   (if (<= t -0.48)
     t_1
     (if (<= t 0.74) (+ 0.5 (* (* t t) (+ 1.0 (* t (+ t -2.0))))) t_1))))
double code(double t) {
	double t_1 = 0.8333333333333334 + ((((0.037037037037037035 + (0.04938271604938271 / t)) / t) - 0.2222222222222222) / t);
	double tmp;
	if (t <= -0.48) {
		tmp = t_1;
	} else if (t <= 0.74) {
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 0.8333333333333334d0 + ((((0.037037037037037035d0 + (0.04938271604938271d0 / t)) / t) - 0.2222222222222222d0) / t)
    if (t <= (-0.48d0)) then
        tmp = t_1
    else if (t <= 0.74d0) then
        tmp = 0.5d0 + ((t * t) * (1.0d0 + (t * (t + (-2.0d0)))))
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double t) {
	double t_1 = 0.8333333333333334 + ((((0.037037037037037035 + (0.04938271604938271 / t)) / t) - 0.2222222222222222) / t);
	double tmp;
	if (t <= -0.48) {
		tmp = t_1;
	} else if (t <= 0.74) {
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(t):
	t_1 = 0.8333333333333334 + ((((0.037037037037037035 + (0.04938271604938271 / t)) / t) - 0.2222222222222222) / t)
	tmp = 0
	if t <= -0.48:
		tmp = t_1
	elif t <= 0.74:
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))))
	else:
		tmp = t_1
	return tmp
function code(t)
	t_1 = Float64(0.8333333333333334 + Float64(Float64(Float64(Float64(0.037037037037037035 + Float64(0.04938271604938271 / t)) / t) - 0.2222222222222222) / t))
	tmp = 0.0
	if (t <= -0.48)
		tmp = t_1;
	elseif (t <= 0.74)
		tmp = Float64(0.5 + Float64(Float64(t * t) * Float64(1.0 + Float64(t * Float64(t + -2.0)))));
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(t)
	t_1 = 0.8333333333333334 + ((((0.037037037037037035 + (0.04938271604938271 / t)) / t) - 0.2222222222222222) / t);
	tmp = 0.0;
	if (t <= -0.48)
		tmp = t_1;
	elseif (t <= 0.74)
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))));
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(N[(N[(N[(0.037037037037037035 + N[(0.04938271604938271 / t), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision] - 0.2222222222222222), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.48], t$95$1, If[LessEqual[t, 0.74], N[(0.5 + N[(N[(t * t), $MachinePrecision] * N[(1.0 + N[(t * N[(t + -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035 + \frac{0.04938271604938271}{t}}{t} - 0.2222222222222222}{t}\\
\mathbf{if}\;t \leq -0.48:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t \leq 0.74:\\
\;\;\;\;0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -0.47999999999999998 or 0.73999999999999999 < t

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around -inf

      \[\leadsto \color{blue}{\frac{5}{6} + -1 \cdot \frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}} \]
    5. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{5}{6} + \left(\mathsf{neg}\left(\frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}\right)\right) \]
      2. unsub-negN/A

        \[\leadsto \frac{5}{6} - \color{blue}{\frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}} \]
      3. --lowering--.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \color{blue}{\left(\frac{\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}}{t}\right)}\right) \]
      4. /-lowering-/.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{2}{9} + -1 \cdot \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}\right), \color{blue}{t}\right)\right) \]
      5. mul-1-negN/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{2}{9} + \left(\mathsf{neg}\left(\frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}\right)\right)\right), t\right)\right) \]
      6. unsub-negN/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{2}{9} - \frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}\right), t\right)\right) \]
      7. --lowering--.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(\frac{2}{9}, \left(\frac{\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}}{t}\right)\right), t\right)\right) \]
      8. /-lowering-/.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(\frac{2}{9}, \mathsf{/.f64}\left(\left(\frac{1}{27} + \frac{4}{81} \cdot \frac{1}{t}\right), t\right)\right), t\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(\frac{2}{9}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{27}, \left(\frac{4}{81} \cdot \frac{1}{t}\right)\right), t\right)\right), t\right)\right) \]
      10. associate-*r/N/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(\frac{2}{9}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{27}, \left(\frac{\frac{4}{81} \cdot 1}{t}\right)\right), t\right)\right), t\right)\right) \]
      11. metadata-evalN/A

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(\frac{2}{9}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{27}, \left(\frac{\frac{4}{81}}{t}\right)\right), t\right)\right), t\right)\right) \]
      12. /-lowering-/.f6498.8%

        \[\leadsto \mathsf{\_.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{\_.f64}\left(\frac{2}{9}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{27}, \mathsf{/.f64}\left(\frac{4}{81}, t\right)\right), t\right)\right), t\right)\right) \]
    6. Simplified98.8%

      \[\leadsto \color{blue}{0.8333333333333334 - \frac{0.2222222222222222 - \frac{0.037037037037037035 + \frac{0.04938271604938271}{t}}{t}}{t}} \]

    if -0.47999999999999998 < t < 0.73999999999999999

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

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

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2} \cdot \left(1 + t \cdot \left(t - 2\right)\right)\right)}\right) \]
      2. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\left({t}^{2}\right), \color{blue}{\left(1 + t \cdot \left(t - 2\right)\right)}\right)\right) \]
      3. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\left(t \cdot t\right), \left(\color{blue}{1} + t \cdot \left(t - 2\right)\right)\right)\right) \]
      4. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \left(\color{blue}{1} + t \cdot \left(t - 2\right)\right)\right)\right) \]
      5. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \color{blue}{\left(t \cdot \left(t - 2\right)\right)}\right)\right)\right) \]
      6. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \color{blue}{\left(t - 2\right)}\right)\right)\right)\right) \]
      7. sub-negN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \left(t + \color{blue}{\left(\mathsf{neg}\left(2\right)\right)}\right)\right)\right)\right)\right) \]
      8. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \left(t + -2\right)\right)\right)\right)\right) \]
      9. +-lowering-+.f64100.0%

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \mathsf{+.f64}\left(t, \color{blue}{-2}\right)\right)\right)\right)\right) \]
    6. Simplified100.0%

      \[\leadsto \color{blue}{0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq -0.48:\\ \;\;\;\;0.8333333333333334 + \frac{\frac{0.037037037037037035 + \frac{0.04938271604938271}{t}}{t} - 0.2222222222222222}{t}\\ \mathbf{elif}\;t \leq 0.74:\\ \;\;\;\;0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334 + \frac{\frac{0.037037037037037035 + \frac{0.04938271604938271}{t}}{t} - 0.2222222222222222}{t}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.3% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -0.58:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.58:\\ \;\;\;\;0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1
         (+
          0.8333333333333334
          (/ (+ (/ 0.037037037037037035 t) -0.2222222222222222) t))))
   (if (<= t -0.58)
     t_1
     (if (<= t 0.58) (+ 0.5 (* (* t t) (+ 1.0 (* t (+ t -2.0))))) t_1))))
double code(double t) {
	double t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	double tmp;
	if (t <= -0.58) {
		tmp = t_1;
	} else if (t <= 0.58) {
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 0.8333333333333334d0 + (((0.037037037037037035d0 / t) + (-0.2222222222222222d0)) / t)
    if (t <= (-0.58d0)) then
        tmp = t_1
    else if (t <= 0.58d0) then
        tmp = 0.5d0 + ((t * t) * (1.0d0 + (t * (t + (-2.0d0)))))
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double t) {
	double t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	double tmp;
	if (t <= -0.58) {
		tmp = t_1;
	} else if (t <= 0.58) {
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(t):
	t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t)
	tmp = 0
	if t <= -0.58:
		tmp = t_1
	elif t <= 0.58:
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))))
	else:
		tmp = t_1
	return tmp
function code(t)
	t_1 = Float64(0.8333333333333334 + Float64(Float64(Float64(0.037037037037037035 / t) + -0.2222222222222222) / t))
	tmp = 0.0
	if (t <= -0.58)
		tmp = t_1;
	elseif (t <= 0.58)
		tmp = Float64(0.5 + Float64(Float64(t * t) * Float64(1.0 + Float64(t * Float64(t + -2.0)))));
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(t)
	t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	tmp = 0.0;
	if (t <= -0.58)
		tmp = t_1;
	elseif (t <= 0.58)
		tmp = 0.5 + ((t * t) * (1.0 + (t * (t + -2.0))));
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(N[(N[(0.037037037037037035 / t), $MachinePrecision] + -0.2222222222222222), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.58], t$95$1, If[LessEqual[t, 0.58], N[(0.5 + N[(N[(t * t), $MachinePrecision] * N[(1.0 + N[(t * N[(t + -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}\\
\mathbf{if}\;t \leq -0.58:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t \leq 0.58:\\
\;\;\;\;0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -0.57999999999999996 or 0.57999999999999996 < t

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

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

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

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

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

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

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

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

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

        \[\leadsto \frac{5}{6} + \frac{\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}}{\color{blue}{t}} \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\frac{\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}}{t}\right)}\right) \]
      10. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}\right), \color{blue}{t}\right)\right) \]
      11. sub-negN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t} + \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      12. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      13. associate-*r/N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{1}{27} \cdot 1}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{1}{27}}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      15. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{1}{27}, t\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      16. metadata-eval98.6%

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{1}{27}, t\right), \frac{-2}{9}\right), t\right)\right) \]
    6. Simplified98.6%

      \[\leadsto \color{blue}{0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}} \]

    if -0.57999999999999996 < t < 0.57999999999999996

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

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

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2} \cdot \left(1 + t \cdot \left(t - 2\right)\right)\right)}\right) \]
      2. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\left({t}^{2}\right), \color{blue}{\left(1 + t \cdot \left(t - 2\right)\right)}\right)\right) \]
      3. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\left(t \cdot t\right), \left(\color{blue}{1} + t \cdot \left(t - 2\right)\right)\right)\right) \]
      4. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \left(\color{blue}{1} + t \cdot \left(t - 2\right)\right)\right)\right) \]
      5. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \color{blue}{\left(t \cdot \left(t - 2\right)\right)}\right)\right)\right) \]
      6. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \color{blue}{\left(t - 2\right)}\right)\right)\right)\right) \]
      7. sub-negN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \left(t + \color{blue}{\left(\mathsf{neg}\left(2\right)\right)}\right)\right)\right)\right)\right) \]
      8. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \left(t + -2\right)\right)\right)\right)\right) \]
      9. +-lowering-+.f64100.0%

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(t, t\right), \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \mathsf{+.f64}\left(t, \color{blue}{-2}\right)\right)\right)\right)\right) \]
    6. Simplified100.0%

      \[\leadsto \color{blue}{0.5 + \left(t \cdot t\right) \cdot \left(1 + t \cdot \left(t + -2\right)\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 4: 99.3% accurate, 1.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -0.6:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.45:\\ \;\;\;\;0.5 + t \cdot \left(t \cdot \left(1 + t \cdot -2\right)\right)\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1
         (+
          0.8333333333333334
          (/ (+ (/ 0.037037037037037035 t) -0.2222222222222222) t))))
   (if (<= t -0.6)
     t_1
     (if (<= t 0.45) (+ 0.5 (* t (* t (+ 1.0 (* t -2.0))))) t_1))))
double code(double t) {
	double t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	double tmp;
	if (t <= -0.6) {
		tmp = t_1;
	} else if (t <= 0.45) {
		tmp = 0.5 + (t * (t * (1.0 + (t * -2.0))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 0.8333333333333334d0 + (((0.037037037037037035d0 / t) + (-0.2222222222222222d0)) / t)
    if (t <= (-0.6d0)) then
        tmp = t_1
    else if (t <= 0.45d0) then
        tmp = 0.5d0 + (t * (t * (1.0d0 + (t * (-2.0d0)))))
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double t) {
	double t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	double tmp;
	if (t <= -0.6) {
		tmp = t_1;
	} else if (t <= 0.45) {
		tmp = 0.5 + (t * (t * (1.0 + (t * -2.0))));
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(t):
	t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t)
	tmp = 0
	if t <= -0.6:
		tmp = t_1
	elif t <= 0.45:
		tmp = 0.5 + (t * (t * (1.0 + (t * -2.0))))
	else:
		tmp = t_1
	return tmp
function code(t)
	t_1 = Float64(0.8333333333333334 + Float64(Float64(Float64(0.037037037037037035 / t) + -0.2222222222222222) / t))
	tmp = 0.0
	if (t <= -0.6)
		tmp = t_1;
	elseif (t <= 0.45)
		tmp = Float64(0.5 + Float64(t * Float64(t * Float64(1.0 + Float64(t * -2.0)))));
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(t)
	t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	tmp = 0.0;
	if (t <= -0.6)
		tmp = t_1;
	elseif (t <= 0.45)
		tmp = 0.5 + (t * (t * (1.0 + (t * -2.0))));
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(N[(N[(0.037037037037037035 / t), $MachinePrecision] + -0.2222222222222222), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.6], t$95$1, If[LessEqual[t, 0.45], N[(0.5 + N[(t * N[(t * N[(1.0 + N[(t * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}\\
\mathbf{if}\;t \leq -0.6:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t \leq 0.45:\\
\;\;\;\;0.5 + t \cdot \left(t \cdot \left(1 + t \cdot -2\right)\right)\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -0.599999999999999978 or 0.450000000000000011 < t

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

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

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

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

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

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

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

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

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

        \[\leadsto \frac{5}{6} + \frac{\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}}{\color{blue}{t}} \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\frac{\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}}{t}\right)}\right) \]
      10. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}\right), \color{blue}{t}\right)\right) \]
      11. sub-negN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t} + \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      12. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      13. associate-*r/N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{1}{27} \cdot 1}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{1}{27}}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      15. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{1}{27}, t\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      16. metadata-eval98.6%

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{1}{27}, t\right), \frac{-2}{9}\right), t\right)\right) \]
    6. Simplified98.6%

      \[\leadsto \color{blue}{0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}} \]

    if -0.599999999999999978 < t < 0.450000000000000011

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

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

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2} \cdot \left(1 + -2 \cdot t\right)\right)}\right) \]
      2. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \left(\left(t \cdot t\right) \cdot \left(\color{blue}{1} + -2 \cdot t\right)\right)\right) \]
      3. associate-*l*N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \left(t \cdot \color{blue}{\left(t \cdot \left(1 + -2 \cdot t\right)\right)}\right)\right) \]
      4. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \color{blue}{\left(t \cdot \left(1 + -2 \cdot t\right)\right)}\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \mathsf{*.f64}\left(t, \color{blue}{\left(1 + -2 \cdot t\right)}\right)\right)\right) \]
      6. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \mathsf{*.f64}\left(t, \mathsf{+.f64}\left(1, \color{blue}{\left(-2 \cdot t\right)}\right)\right)\right)\right) \]
      7. *-commutativeN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \mathsf{*.f64}\left(t, \mathsf{+.f64}\left(1, \left(t \cdot \color{blue}{-2}\right)\right)\right)\right)\right) \]
      8. *-lowering-*.f6499.9%

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \mathsf{*.f64}\left(t, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(t, \color{blue}{-2}\right)\right)\right)\right)\right) \]
    6. Simplified99.9%

      \[\leadsto \color{blue}{0.5 + t \cdot \left(t \cdot \left(1 + t \cdot -2\right)\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 5: 99.2% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -0.82:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.24:\\ \;\;\;\;0.5 + t \cdot t\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1
         (+
          0.8333333333333334
          (/ (+ (/ 0.037037037037037035 t) -0.2222222222222222) t))))
   (if (<= t -0.82) t_1 (if (<= t 0.24) (+ 0.5 (* t t)) t_1))))
double code(double t) {
	double t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	double tmp;
	if (t <= -0.82) {
		tmp = t_1;
	} else if (t <= 0.24) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 0.8333333333333334d0 + (((0.037037037037037035d0 / t) + (-0.2222222222222222d0)) / t)
    if (t <= (-0.82d0)) then
        tmp = t_1
    else if (t <= 0.24d0) then
        tmp = 0.5d0 + (t * t)
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double t) {
	double t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	double tmp;
	if (t <= -0.82) {
		tmp = t_1;
	} else if (t <= 0.24) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(t):
	t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t)
	tmp = 0
	if t <= -0.82:
		tmp = t_1
	elif t <= 0.24:
		tmp = 0.5 + (t * t)
	else:
		tmp = t_1
	return tmp
function code(t)
	t_1 = Float64(0.8333333333333334 + Float64(Float64(Float64(0.037037037037037035 / t) + -0.2222222222222222) / t))
	tmp = 0.0
	if (t <= -0.82)
		tmp = t_1;
	elseif (t <= 0.24)
		tmp = Float64(0.5 + Float64(t * t));
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(t)
	t_1 = 0.8333333333333334 + (((0.037037037037037035 / t) + -0.2222222222222222) / t);
	tmp = 0.0;
	if (t <= -0.82)
		tmp = t_1;
	elseif (t <= 0.24)
		tmp = 0.5 + (t * t);
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(N[(N[(0.037037037037037035 / t), $MachinePrecision] + -0.2222222222222222), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.82], t$95$1, If[LessEqual[t, 0.24], N[(0.5 + N[(t * t), $MachinePrecision]), $MachinePrecision], t$95$1]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}\\
\mathbf{if}\;t \leq -0.82:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t \leq 0.24:\\
\;\;\;\;0.5 + t \cdot t\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -0.819999999999999951 or 0.23999999999999999 < t

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

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

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

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

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

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

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

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

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

        \[\leadsto \frac{5}{6} + \frac{\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}}{\color{blue}{t}} \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\frac{\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}}{t}\right)}\right) \]
      10. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t} - \frac{2}{9}\right), \color{blue}{t}\right)\right) \]
      11. sub-negN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t} + \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      12. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{1}{27} \cdot \frac{1}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      13. associate-*r/N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{1}{27} \cdot 1}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{1}{27}}{t}\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      15. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{1}{27}, t\right), \left(\mathsf{neg}\left(\frac{2}{9}\right)\right)\right), t\right)\right) \]
      16. metadata-eval98.6%

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{1}{27}, t\right), \frac{-2}{9}\right), t\right)\right) \]
    6. Simplified98.6%

      \[\leadsto \color{blue}{0.8333333333333334 + \frac{\frac{0.037037037037037035}{t} + -0.2222222222222222}{t}} \]

    if -0.819999999999999951 < t < 0.23999999999999999

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2}} \]
    5. Step-by-step derivation
      1. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2}\right)}\right) \]
      2. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \left(t \cdot \color{blue}{t}\right)\right) \]
      3. *-lowering-*.f6499.7%

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \color{blue}{t}\right)\right) \]
    6. Simplified99.7%

      \[\leadsto \color{blue}{0.5 + t \cdot t} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 6: 100.0% accurate, 1.5× speedup?

\[\begin{array}{l} \\ 1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)} \end{array} \]
(FPCore (t)
 :precision binary64
 (+ 1.0 (/ 1.0 (+ -6.0 (* (/ 2.0 (+ 1.0 t)) (+ (/ 2.0 (- -1.0 t)) 4.0))))))
double code(double t) {
	return 1.0 + (1.0 / (-6.0 + ((2.0 / (1.0 + t)) * ((2.0 / (-1.0 - t)) + 4.0))));
}
real(8) function code(t)
    real(8), intent (in) :: t
    code = 1.0d0 + (1.0d0 / ((-6.0d0) + ((2.0d0 / (1.0d0 + t)) * ((2.0d0 / ((-1.0d0) - t)) + 4.0d0))))
end function
public static double code(double t) {
	return 1.0 + (1.0 / (-6.0 + ((2.0 / (1.0 + t)) * ((2.0 / (-1.0 - t)) + 4.0))));
}
def code(t):
	return 1.0 + (1.0 / (-6.0 + ((2.0 / (1.0 + t)) * ((2.0 / (-1.0 - t)) + 4.0))))
function code(t)
	return Float64(1.0 + Float64(1.0 / Float64(-6.0 + Float64(Float64(2.0 / Float64(1.0 + t)) * Float64(Float64(2.0 / Float64(-1.0 - t)) + 4.0)))))
end
function tmp = code(t)
	tmp = 1.0 + (1.0 / (-6.0 + ((2.0 / (1.0 + t)) * ((2.0 / (-1.0 - t)) + 4.0))));
end
code[t_] := N[(1.0 + N[(1.0 / N[(-6.0 + N[(N[(2.0 / N[(1.0 + t), $MachinePrecision]), $MachinePrecision] * N[(N[(2.0 / N[(-1.0 - t), $MachinePrecision]), $MachinePrecision] + 4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}
\end{array}
Derivation
  1. Initial program 100.0%

    \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
  2. Simplified100.0%

    \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
  3. Add Preprocessing
  4. Add Preprocessing

Alternative 7: 99.0% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -0.8:\\ \;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222}{t}\\ \mathbf{elif}\;t \leq 0.58:\\ \;\;\;\;0.5 + t \cdot t\\ \mathbf{else}:\\ \;\;\;\;1 - \left(\frac{0.2222222222222222}{t} + 0.16666666666666666\right)\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (if (<= t -0.8)
   (+ 0.8333333333333334 (/ -0.2222222222222222 t))
   (if (<= t 0.58)
     (+ 0.5 (* t t))
     (- 1.0 (+ (/ 0.2222222222222222 t) 0.16666666666666666)))))
double code(double t) {
	double tmp;
	if (t <= -0.8) {
		tmp = 0.8333333333333334 + (-0.2222222222222222 / t);
	} else if (t <= 0.58) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = 1.0 - ((0.2222222222222222 / t) + 0.16666666666666666);
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: tmp
    if (t <= (-0.8d0)) then
        tmp = 0.8333333333333334d0 + ((-0.2222222222222222d0) / t)
    else if (t <= 0.58d0) then
        tmp = 0.5d0 + (t * t)
    else
        tmp = 1.0d0 - ((0.2222222222222222d0 / t) + 0.16666666666666666d0)
    end if
    code = tmp
end function
public static double code(double t) {
	double tmp;
	if (t <= -0.8) {
		tmp = 0.8333333333333334 + (-0.2222222222222222 / t);
	} else if (t <= 0.58) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = 1.0 - ((0.2222222222222222 / t) + 0.16666666666666666);
	}
	return tmp;
}
def code(t):
	tmp = 0
	if t <= -0.8:
		tmp = 0.8333333333333334 + (-0.2222222222222222 / t)
	elif t <= 0.58:
		tmp = 0.5 + (t * t)
	else:
		tmp = 1.0 - ((0.2222222222222222 / t) + 0.16666666666666666)
	return tmp
function code(t)
	tmp = 0.0
	if (t <= -0.8)
		tmp = Float64(0.8333333333333334 + Float64(-0.2222222222222222 / t));
	elseif (t <= 0.58)
		tmp = Float64(0.5 + Float64(t * t));
	else
		tmp = Float64(1.0 - Float64(Float64(0.2222222222222222 / t) + 0.16666666666666666));
	end
	return tmp
end
function tmp_2 = code(t)
	tmp = 0.0;
	if (t <= -0.8)
		tmp = 0.8333333333333334 + (-0.2222222222222222 / t);
	elseif (t <= 0.58)
		tmp = 0.5 + (t * t);
	else
		tmp = 1.0 - ((0.2222222222222222 / t) + 0.16666666666666666);
	end
	tmp_2 = tmp;
end
code[t_] := If[LessEqual[t, -0.8], N[(0.8333333333333334 + N[(-0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision], If[LessEqual[t, 0.58], N[(0.5 + N[(t * t), $MachinePrecision]), $MachinePrecision], N[(1.0 - N[(N[(0.2222222222222222 / t), $MachinePrecision] + 0.16666666666666666), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq -0.8:\\
\;\;\;\;0.8333333333333334 + \frac{-0.2222222222222222}{t}\\

\mathbf{elif}\;t \leq 0.58:\\
\;\;\;\;0.5 + t \cdot t\\

\mathbf{else}:\\
\;\;\;\;1 - \left(\frac{0.2222222222222222}{t} + 0.16666666666666666\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if t < -0.80000000000000004

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

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

        \[\leadsto \frac{5}{6} + \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)} \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)}\right) \]
      3. associate-*r/N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9} \cdot 1}{t}\right)\right)\right) \]
      4. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9}}{t}\right)\right)\right) \]
      5. distribute-neg-fracN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\frac{\mathsf{neg}\left(\frac{2}{9}\right)}{\color{blue}{t}}\right)\right) \]
      6. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\mathsf{neg}\left(\frac{2}{9}\right)\right), \color{blue}{t}\right)\right) \]
      7. metadata-eval97.7%

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\frac{-2}{9}, t\right)\right) \]
    6. Simplified97.7%

      \[\leadsto \color{blue}{0.8333333333333334 + \frac{-0.2222222222222222}{t}} \]

    if -0.80000000000000004 < t < 0.57999999999999996

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2}} \]
    5. Step-by-step derivation
      1. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2}\right)}\right) \]
      2. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \left(t \cdot \color{blue}{t}\right)\right) \]
      3. *-lowering-*.f6499.7%

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \color{blue}{t}\right)\right) \]
    6. Simplified99.7%

      \[\leadsto \color{blue}{0.5 + t \cdot t} \]

    if 0.57999999999999996 < t

    1. Initial program 100.0%

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

      \[\leadsto \mathsf{\_.f64}\left(1, \color{blue}{\left(\frac{1}{6} + \frac{2}{9} \cdot \frac{1}{t}\right)}\right) \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \mathsf{\_.f64}\left(1, \left(\frac{2}{9} \cdot \frac{1}{t} + \color{blue}{\frac{1}{6}}\right)\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{\_.f64}\left(1, \mathsf{+.f64}\left(\left(\frac{2}{9} \cdot \frac{1}{t}\right), \color{blue}{\frac{1}{6}}\right)\right) \]
      3. associate-*r/N/A

        \[\leadsto \mathsf{\_.f64}\left(1, \mathsf{+.f64}\left(\left(\frac{\frac{2}{9} \cdot 1}{t}\right), \frac{1}{6}\right)\right) \]
      4. metadata-evalN/A

        \[\leadsto \mathsf{\_.f64}\left(1, \mathsf{+.f64}\left(\left(\frac{\frac{2}{9}}{t}\right), \frac{1}{6}\right)\right) \]
      5. /-lowering-/.f6498.5%

        \[\leadsto \mathsf{\_.f64}\left(1, \mathsf{+.f64}\left(\mathsf{/.f64}\left(\frac{2}{9}, t\right), \frac{1}{6}\right)\right) \]
    5. Simplified98.5%

      \[\leadsto 1 - \color{blue}{\left(\frac{0.2222222222222222}{t} + 0.16666666666666666\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 8: 99.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 0.8333333333333334 + \frac{-0.2222222222222222}{t}\\ \mathbf{if}\;t \leq -0.8:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t \leq 0.58:\\ \;\;\;\;0.5 + t \cdot t\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (let* ((t_1 (+ 0.8333333333333334 (/ -0.2222222222222222 t))))
   (if (<= t -0.8) t_1 (if (<= t 0.58) (+ 0.5 (* t t)) t_1))))
double code(double t) {
	double t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
	double tmp;
	if (t <= -0.8) {
		tmp = t_1;
	} else if (t <= 0.58) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = t_1;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 0.8333333333333334d0 + ((-0.2222222222222222d0) / t)
    if (t <= (-0.8d0)) then
        tmp = t_1
    else if (t <= 0.58d0) then
        tmp = 0.5d0 + (t * t)
    else
        tmp = t_1
    end if
    code = tmp
end function
public static double code(double t) {
	double t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
	double tmp;
	if (t <= -0.8) {
		tmp = t_1;
	} else if (t <= 0.58) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = t_1;
	}
	return tmp;
}
def code(t):
	t_1 = 0.8333333333333334 + (-0.2222222222222222 / t)
	tmp = 0
	if t <= -0.8:
		tmp = t_1
	elif t <= 0.58:
		tmp = 0.5 + (t * t)
	else:
		tmp = t_1
	return tmp
function code(t)
	t_1 = Float64(0.8333333333333334 + Float64(-0.2222222222222222 / t))
	tmp = 0.0
	if (t <= -0.8)
		tmp = t_1;
	elseif (t <= 0.58)
		tmp = Float64(0.5 + Float64(t * t));
	else
		tmp = t_1;
	end
	return tmp
end
function tmp_2 = code(t)
	t_1 = 0.8333333333333334 + (-0.2222222222222222 / t);
	tmp = 0.0;
	if (t <= -0.8)
		tmp = t_1;
	elseif (t <= 0.58)
		tmp = 0.5 + (t * t);
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end
code[t_] := Block[{t$95$1 = N[(0.8333333333333334 + N[(-0.2222222222222222 / t), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t, -0.8], t$95$1, If[LessEqual[t, 0.58], N[(0.5 + N[(t * t), $MachinePrecision]), $MachinePrecision], t$95$1]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 0.8333333333333334 + \frac{-0.2222222222222222}{t}\\
\mathbf{if}\;t \leq -0.8:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t \leq 0.58:\\
\;\;\;\;0.5 + t \cdot t\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -0.80000000000000004 or 0.57999999999999996 < t

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

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

        \[\leadsto \frac{5}{6} + \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)} \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \color{blue}{\left(\mathsf{neg}\left(\frac{2}{9} \cdot \frac{1}{t}\right)\right)}\right) \]
      3. associate-*r/N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9} \cdot 1}{t}\right)\right)\right) \]
      4. metadata-evalN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\mathsf{neg}\left(\frac{\frac{2}{9}}{t}\right)\right)\right) \]
      5. distribute-neg-fracN/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \left(\frac{\mathsf{neg}\left(\frac{2}{9}\right)}{\color{blue}{t}}\right)\right) \]
      6. /-lowering-/.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\left(\mathsf{neg}\left(\frac{2}{9}\right)\right), \color{blue}{t}\right)\right) \]
      7. metadata-eval98.0%

        \[\leadsto \mathsf{+.f64}\left(\frac{5}{6}, \mathsf{/.f64}\left(\frac{-2}{9}, t\right)\right) \]
    6. Simplified98.0%

      \[\leadsto \color{blue}{0.8333333333333334 + \frac{-0.2222222222222222}{t}} \]

    if -0.80000000000000004 < t < 0.57999999999999996

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0

      \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2}} \]
    5. Step-by-step derivation
      1. +-lowering-+.f64N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2}\right)}\right) \]
      2. unpow2N/A

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \left(t \cdot \color{blue}{t}\right)\right) \]
      3. *-lowering-*.f6499.7%

        \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \color{blue}{t}\right)\right) \]
    6. Simplified99.7%

      \[\leadsto \color{blue}{0.5 + t \cdot t} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 9: 98.6% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -0.92:\\ \;\;\;\;0.8333333333333334\\ \mathbf{elif}\;t \leq 0.58:\\ \;\;\;\;0.5 + t \cdot t\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \end{array} \]
(FPCore (t)
 :precision binary64
 (if (<= t -0.92)
   0.8333333333333334
   (if (<= t 0.58) (+ 0.5 (* t t)) 0.8333333333333334)))
double code(double t) {
	double tmp;
	if (t <= -0.92) {
		tmp = 0.8333333333333334;
	} else if (t <= 0.58) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = 0.8333333333333334;
	}
	return tmp;
}
real(8) function code(t)
    real(8), intent (in) :: t
    real(8) :: tmp
    if (t <= (-0.92d0)) then
        tmp = 0.8333333333333334d0
    else if (t <= 0.58d0) then
        tmp = 0.5d0 + (t * t)
    else
        tmp = 0.8333333333333334d0
    end if
    code = tmp
end function
public static double code(double t) {
	double tmp;
	if (t <= -0.92) {
		tmp = 0.8333333333333334;
	} else if (t <= 0.58) {
		tmp = 0.5 + (t * t);
	} else {
		tmp = 0.8333333333333334;
	}
	return tmp;
}
def code(t):
	tmp = 0
	if t <= -0.92:
		tmp = 0.8333333333333334
	elif t <= 0.58:
		tmp = 0.5 + (t * t)
	else:
		tmp = 0.8333333333333334
	return tmp
function code(t)
	tmp = 0.0
	if (t <= -0.92)
		tmp = 0.8333333333333334;
	elseif (t <= 0.58)
		tmp = Float64(0.5 + Float64(t * t));
	else
		tmp = 0.8333333333333334;
	end
	return tmp
end
function tmp_2 = code(t)
	tmp = 0.0;
	if (t <= -0.92)
		tmp = 0.8333333333333334;
	elseif (t <= 0.58)
		tmp = 0.5 + (t * t);
	else
		tmp = 0.8333333333333334;
	end
	tmp_2 = tmp;
end
code[t_] := If[LessEqual[t, -0.92], 0.8333333333333334, If[LessEqual[t, 0.58], N[(0.5 + N[(t * t), $MachinePrecision]), $MachinePrecision], 0.8333333333333334]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;t \leq -0.92:\\
\;\;\;\;0.8333333333333334\\

\mathbf{elif}\;t \leq 0.58:\\
\;\;\;\;0.5 + t \cdot t\\

\mathbf{else}:\\
\;\;\;\;0.8333333333333334\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < -0.92000000000000004 or 0.57999999999999996 < t

    1. Initial program 100.0%

      \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
    2. Simplified100.0%

      \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
    3. Add Preprocessing
    4. Taylor expanded in t around inf

      \[\leadsto \color{blue}{\frac{5}{6}} \]
    5. Step-by-step derivation
      1. Simplified96.9%

        \[\leadsto \color{blue}{0.8333333333333334} \]

      if -0.92000000000000004 < t < 0.57999999999999996

      1. Initial program 100.0%

        \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
      2. Simplified100.0%

        \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
      3. Add Preprocessing
      4. Taylor expanded in t around 0

        \[\leadsto \color{blue}{\frac{1}{2} + {t}^{2}} \]
      5. Step-by-step derivation
        1. +-lowering-+.f64N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \color{blue}{\left({t}^{2}\right)}\right) \]
        2. unpow2N/A

          \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \left(t \cdot \color{blue}{t}\right)\right) \]
        3. *-lowering-*.f6499.7%

          \[\leadsto \mathsf{+.f64}\left(\frac{1}{2}, \mathsf{*.f64}\left(t, \color{blue}{t}\right)\right) \]
      6. Simplified99.7%

        \[\leadsto \color{blue}{0.5 + t \cdot t} \]
    6. Recombined 2 regimes into one program.
    7. Add Preprocessing

    Alternative 10: 98.4% accurate, 2.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;t \leq -0.34:\\ \;\;\;\;0.8333333333333334\\ \mathbf{elif}\;t \leq 1:\\ \;\;\;\;0.5\\ \mathbf{else}:\\ \;\;\;\;0.8333333333333334\\ \end{array} \end{array} \]
    (FPCore (t)
     :precision binary64
     (if (<= t -0.34) 0.8333333333333334 (if (<= t 1.0) 0.5 0.8333333333333334)))
    double code(double t) {
    	double tmp;
    	if (t <= -0.34) {
    		tmp = 0.8333333333333334;
    	} else if (t <= 1.0) {
    		tmp = 0.5;
    	} else {
    		tmp = 0.8333333333333334;
    	}
    	return tmp;
    }
    
    real(8) function code(t)
        real(8), intent (in) :: t
        real(8) :: tmp
        if (t <= (-0.34d0)) then
            tmp = 0.8333333333333334d0
        else if (t <= 1.0d0) then
            tmp = 0.5d0
        else
            tmp = 0.8333333333333334d0
        end if
        code = tmp
    end function
    
    public static double code(double t) {
    	double tmp;
    	if (t <= -0.34) {
    		tmp = 0.8333333333333334;
    	} else if (t <= 1.0) {
    		tmp = 0.5;
    	} else {
    		tmp = 0.8333333333333334;
    	}
    	return tmp;
    }
    
    def code(t):
    	tmp = 0
    	if t <= -0.34:
    		tmp = 0.8333333333333334
    	elif t <= 1.0:
    		tmp = 0.5
    	else:
    		tmp = 0.8333333333333334
    	return tmp
    
    function code(t)
    	tmp = 0.0
    	if (t <= -0.34)
    		tmp = 0.8333333333333334;
    	elseif (t <= 1.0)
    		tmp = 0.5;
    	else
    		tmp = 0.8333333333333334;
    	end
    	return tmp
    end
    
    function tmp_2 = code(t)
    	tmp = 0.0;
    	if (t <= -0.34)
    		tmp = 0.8333333333333334;
    	elseif (t <= 1.0)
    		tmp = 0.5;
    	else
    		tmp = 0.8333333333333334;
    	end
    	tmp_2 = tmp;
    end
    
    code[t_] := If[LessEqual[t, -0.34], 0.8333333333333334, If[LessEqual[t, 1.0], 0.5, 0.8333333333333334]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;t \leq -0.34:\\
    \;\;\;\;0.8333333333333334\\
    
    \mathbf{elif}\;t \leq 1:\\
    \;\;\;\;0.5\\
    
    \mathbf{else}:\\
    \;\;\;\;0.8333333333333334\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if t < -0.340000000000000024 or 1 < t

      1. Initial program 100.0%

        \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
      2. Simplified100.0%

        \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
      3. Add Preprocessing
      4. Taylor expanded in t around inf

        \[\leadsto \color{blue}{\frac{5}{6}} \]
      5. Step-by-step derivation
        1. Simplified96.9%

          \[\leadsto \color{blue}{0.8333333333333334} \]

        if -0.340000000000000024 < t < 1

        1. Initial program 100.0%

          \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Simplified100.0%

          \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
        3. Add Preprocessing
        4. Taylor expanded in t around 0

          \[\leadsto \color{blue}{\frac{1}{2}} \]
        5. Step-by-step derivation
          1. Simplified99.4%

            \[\leadsto \color{blue}{0.5} \]
        6. Recombined 2 regimes into one program.
        7. Add Preprocessing

        Alternative 11: 59.2% accurate, 29.0× 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%

          \[1 - \frac{1}{2 + \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right) \cdot \left(2 - \frac{\frac{2}{t}}{1 + \frac{1}{t}}\right)} \]
        2. Simplified100.0%

          \[\leadsto \color{blue}{1 + \frac{1}{-6 + \frac{2}{1 + t} \cdot \left(\frac{2}{-1 - t} + 4\right)}} \]
        3. Add Preprocessing
        4. Taylor expanded in t around 0

          \[\leadsto \color{blue}{\frac{1}{2}} \]
        5. Step-by-step derivation
          1. Simplified58.6%

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

          Reproduce

          ?
          herbie shell --seed 2024139 
          (FPCore (t)
            :name "Kahan p13 Example 3"
            :precision binary64
            (- 1.0 (/ 1.0 (+ 2.0 (* (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t)))) (- 2.0 (/ (/ 2.0 t) (+ 1.0 (/ 1.0 t)))))))))