Numeric.SpecFunctions:invIncompleteGamma from math-functions-0.1.5.2, B

Percentage Accurate: 73.0% → 99.7%
Time: 14.3s
Alternatives: 13
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ 1 - \log \left(1 - \frac{x - y}{1 - y}\right) \end{array} \]
(FPCore (x y) :precision binary64 (- 1.0 (log (- 1.0 (/ (- x y) (- 1.0 y))))))
double code(double x, double y) {
	return 1.0 - log((1.0 - ((x - y) / (1.0 - y))));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = 1.0d0 - log((1.0d0 - ((x - y) / (1.0d0 - y))))
end function
public static double code(double x, double y) {
	return 1.0 - Math.log((1.0 - ((x - y) / (1.0 - y))));
}
def code(x, y):
	return 1.0 - math.log((1.0 - ((x - y) / (1.0 - y))))
function code(x, y)
	return Float64(1.0 - log(Float64(1.0 - Float64(Float64(x - y) / Float64(1.0 - y)))))
end
function tmp = code(x, y)
	tmp = 1.0 - log((1.0 - ((x - y) / (1.0 - y))));
end
code[x_, y_] := N[(1.0 - N[Log[N[(1.0 - N[(N[(x - y), $MachinePrecision] / N[(1.0 - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - \log \left(1 - \frac{x - y}{1 - y}\right)
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 13 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: 73.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 1 - \log \left(1 - \frac{x - y}{1 - y}\right) \end{array} \]
(FPCore (x y) :precision binary64 (- 1.0 (log (- 1.0 (/ (- x y) (- 1.0 y))))))
double code(double x, double y) {
	return 1.0 - log((1.0 - ((x - y) / (1.0 - y))));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = 1.0d0 - log((1.0d0 - ((x - y) / (1.0d0 - y))))
end function
public static double code(double x, double y) {
	return 1.0 - Math.log((1.0 - ((x - y) / (1.0 - y))));
}
def code(x, y):
	return 1.0 - math.log((1.0 - ((x - y) / (1.0 - y))))
function code(x, y)
	return Float64(1.0 - log(Float64(1.0 - Float64(Float64(x - y) / Float64(1.0 - y)))))
end
function tmp = code(x, y)
	tmp = 1.0 - log((1.0 - ((x - y) / (1.0 - y))));
end
code[x_, y_] := N[(1.0 - N[Log[N[(1.0 - N[(N[(x - y), $MachinePrecision] / N[(1.0 - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - \log \left(1 - \frac{x - y}{1 - y}\right)
\end{array}

Alternative 1: 99.7% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \log \left(-1 + x\right)\\ \mathbf{if}\;y \leq -440000:\\ \;\;\;\;\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 52000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1 - {\left(t\_0 - \log y\right)}^{2}}{\left(1 + t\_0\right) - \log y}\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (log (+ -1.0 x))))
   (if (<= y -440000.0)
     (- (+ (/ -1.0 y) (- 1.0 (log1p (- x)))) (log (/ -1.0 y)))
     (if (<= y 52000000000000.0)
       (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
       (/ (- 1.0 (pow (- t_0 (log y)) 2.0)) (- (+ 1.0 t_0) (log y)))))))
double code(double x, double y) {
	double t_0 = log((-1.0 + x));
	double tmp;
	if (y <= -440000.0) {
		tmp = ((-1.0 / y) + (1.0 - log1p(-x))) - log((-1.0 / y));
	} else if (y <= 52000000000000.0) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 - pow((t_0 - log(y)), 2.0)) / ((1.0 + t_0) - log(y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double t_0 = Math.log((-1.0 + x));
	double tmp;
	if (y <= -440000.0) {
		tmp = ((-1.0 / y) + (1.0 - Math.log1p(-x))) - Math.log((-1.0 / y));
	} else if (y <= 52000000000000.0) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 - Math.pow((t_0 - Math.log(y)), 2.0)) / ((1.0 + t_0) - Math.log(y));
	}
	return tmp;
}
def code(x, y):
	t_0 = math.log((-1.0 + x))
	tmp = 0
	if y <= -440000.0:
		tmp = ((-1.0 / y) + (1.0 - math.log1p(-x))) - math.log((-1.0 / y))
	elif y <= 52000000000000.0:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = (1.0 - math.pow((t_0 - math.log(y)), 2.0)) / ((1.0 + t_0) - math.log(y))
	return tmp
function code(x, y)
	t_0 = log(Float64(-1.0 + x))
	tmp = 0.0
	if (y <= -440000.0)
		tmp = Float64(Float64(Float64(-1.0 / y) + Float64(1.0 - log1p(Float64(-x)))) - log(Float64(-1.0 / y)));
	elseif (y <= 52000000000000.0)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = Float64(Float64(1.0 - (Float64(t_0 - log(y)) ^ 2.0)) / Float64(Float64(1.0 + t_0) - log(y)));
	end
	return tmp
end
code[x_, y_] := Block[{t$95$0 = N[Log[N[(-1.0 + x), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[y, -440000.0], N[(N[(N[(-1.0 / y), $MachinePrecision] + N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 52000000000000.0], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(1.0 - N[Power[N[(t$95$0 - N[Log[y], $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / N[(N[(1.0 + t$95$0), $MachinePrecision] - N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \log \left(-1 + x\right)\\
\mathbf{if}\;y \leq -440000:\\
\;\;\;\;\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)\\

\mathbf{elif}\;y \leq 52000000000000:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{1 - {\left(t\_0 - \log y\right)}^{2}}{\left(1 + t\_0\right) - \log y}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -4.4e5

    1. Initial program 24.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg24.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define24.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac224.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub024.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-24.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval24.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative24.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified24.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.5%

      \[\leadsto \color{blue}{\left(1 + -1 \cdot \frac{\frac{x}{x - 1} - \frac{1}{x - 1}}{y}\right) - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Simplified99.5%

      \[\leadsto \color{blue}{\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]

    if -4.4e5 < y < 5.2e13

    1. Initial program 99.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define100.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac2100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub0100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing

    if 5.2e13 < y

    1. Initial program 66.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg66.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define66.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac266.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub066.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified66.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. flip--65.7%

        \[\leadsto \color{blue}{\frac{1 \cdot 1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right) \cdot \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)}{1 + \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)}} \]
      2. metadata-eval65.7%

        \[\leadsto \frac{\color{blue}{1} - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right) \cdot \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)}{1 + \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
      3. pow265.7%

        \[\leadsto \frac{1 - \color{blue}{{\left(\mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\right)}^{2}}}{1 + \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
      4. +-commutative65.7%

        \[\leadsto \frac{1 - {\left(\mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\right)}^{2}}{\color{blue}{\mathsf{log1p}\left(\frac{x - y}{y + -1}\right) + 1}} \]
    6. Applied egg-rr65.7%

      \[\leadsto \color{blue}{\frac{1 - {\left(\mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\right)}^{2}}{\mathsf{log1p}\left(\frac{x - y}{y + -1}\right) + 1}} \]
    7. Taylor expanded in y around inf 98.7%

      \[\leadsto \color{blue}{\frac{1 - {\left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)}^{2}}{1 + \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)}} \]
    8. Step-by-step derivation
      1. log-rec98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x - 1\right) + \color{blue}{\left(-\log y\right)}\right)}^{2}}{1 + \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
      2. unsub-neg98.7%

        \[\leadsto \frac{1 - {\color{blue}{\left(\log \left(x - 1\right) - \log y\right)}}^{2}}{1 + \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
      3. sub-neg98.7%

        \[\leadsto \frac{1 - {\left(\log \color{blue}{\left(x + \left(-1\right)\right)} - \log y\right)}^{2}}{1 + \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
      4. metadata-eval98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x + \color{blue}{-1}\right) - \log y\right)}^{2}}{1 + \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
      5. associate-+r+98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x + -1\right) - \log y\right)}^{2}}{\color{blue}{\left(1 + \log \left(x - 1\right)\right) + \log \left(\frac{1}{y}\right)}} \]
      6. log-rec98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x + -1\right) - \log y\right)}^{2}}{\left(1 + \log \left(x - 1\right)\right) + \color{blue}{\left(-\log y\right)}} \]
      7. unsub-neg98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x + -1\right) - \log y\right)}^{2}}{\color{blue}{\left(1 + \log \left(x - 1\right)\right) - \log y}} \]
      8. sub-neg98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x + -1\right) - \log y\right)}^{2}}{\left(1 + \log \color{blue}{\left(x + \left(-1\right)\right)}\right) - \log y} \]
      9. metadata-eval98.7%

        \[\leadsto \frac{1 - {\left(\log \left(x + -1\right) - \log y\right)}^{2}}{\left(1 + \log \left(x + \color{blue}{-1}\right)\right) - \log y} \]
    9. Simplified98.7%

      \[\leadsto \color{blue}{\frac{1 - {\left(\log \left(x + -1\right) - \log y\right)}^{2}}{\left(1 + \log \left(x + -1\right)\right) - \log y}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -440000:\\ \;\;\;\;\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 52000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1 - {\left(\log \left(-1 + x\right) - \log y\right)}^{2}}{\left(1 + \log \left(-1 + x\right)\right) - \log y}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.5% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -4200000000000:\\ \;\;\;\;1 - \left(\mathsf{log1p}\left(-x\right) + \log \left(\frac{-1}{y}\right)\right)\\ \mathbf{elif}\;y \leq 3.1 \cdot 10^{+15}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 + \log y\right) - \log \left(-1 + x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -4200000000000.0)
   (- 1.0 (+ (log1p (- x)) (log (/ -1.0 y))))
   (if (<= y 3.1e+15)
     (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
     (- (+ 1.0 (log y)) (log (+ -1.0 x))))))
double code(double x, double y) {
	double tmp;
	if (y <= -4200000000000.0) {
		tmp = 1.0 - (log1p(-x) + log((-1.0 / y)));
	} else if (y <= 3.1e+15) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 + log(y)) - log((-1.0 + x));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -4200000000000.0) {
		tmp = 1.0 - (Math.log1p(-x) + Math.log((-1.0 / y)));
	} else if (y <= 3.1e+15) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 + Math.log(y)) - Math.log((-1.0 + x));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -4200000000000.0:
		tmp = 1.0 - (math.log1p(-x) + math.log((-1.0 / y)))
	elif y <= 3.1e+15:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = (1.0 + math.log(y)) - math.log((-1.0 + x))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -4200000000000.0)
		tmp = Float64(1.0 - Float64(log1p(Float64(-x)) + log(Float64(-1.0 / y))));
	elseif (y <= 3.1e+15)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = Float64(Float64(1.0 + log(y)) - log(Float64(-1.0 + x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -4200000000000.0], N[(1.0 - N[(N[Log[1 + (-x)], $MachinePrecision] + N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 3.1e+15], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(1.0 + N[Log[y], $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 + x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -4200000000000:\\
\;\;\;\;1 - \left(\mathsf{log1p}\left(-x\right) + \log \left(\frac{-1}{y}\right)\right)\\

\mathbf{elif}\;y \leq 3.1 \cdot 10^{+15}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

\mathbf{else}:\\
\;\;\;\;\left(1 + \log y\right) - \log \left(-1 + x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -4.2e12

    1. Initial program 22.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg22.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define22.6%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac222.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub022.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-22.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval22.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative22.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified22.6%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.5%

      \[\leadsto 1 - \color{blue}{\left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. sub-neg99.5%

        \[\leadsto 1 - \left(\log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right) + \log \left(\frac{-1}{y}\right)\right) \]
      2. metadata-eval99.5%

        \[\leadsto 1 - \left(\log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right) + \log \left(\frac{-1}{y}\right)\right) \]
      3. distribute-lft-in99.5%

        \[\leadsto 1 - \left(\log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)} + \log \left(\frac{-1}{y}\right)\right) \]
      4. metadata-eval99.5%

        \[\leadsto 1 - \left(\log \left(-1 \cdot x + \color{blue}{1}\right) + \log \left(\frac{-1}{y}\right)\right) \]
      5. +-commutative99.5%

        \[\leadsto 1 - \left(\log \color{blue}{\left(1 + -1 \cdot x\right)} + \log \left(\frac{-1}{y}\right)\right) \]
      6. log1p-define99.5%

        \[\leadsto 1 - \left(\color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} + \log \left(\frac{-1}{y}\right)\right) \]
      7. mul-1-neg99.5%

        \[\leadsto 1 - \left(\mathsf{log1p}\left(\color{blue}{-x}\right) + \log \left(\frac{-1}{y}\right)\right) \]
    7. Simplified99.5%

      \[\leadsto 1 - \color{blue}{\left(\mathsf{log1p}\left(-x\right) + \log \left(\frac{-1}{y}\right)\right)} \]

    if -4.2e12 < y < 3.1e15

    1. Initial program 99.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define99.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac299.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub099.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-99.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval99.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative99.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified99.8%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing

    if 3.1e15 < y

    1. Initial program 66.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg66.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define66.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac266.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub066.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified66.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 98.7%

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. +-commutative98.7%

        \[\leadsto 1 - \color{blue}{\left(\log \left(\frac{1}{y}\right) + \log \left(x - 1\right)\right)} \]
      2. associate--r+98.7%

        \[\leadsto \color{blue}{\left(1 - \log \left(\frac{1}{y}\right)\right) - \log \left(x - 1\right)} \]
      3. sub-neg98.7%

        \[\leadsto \color{blue}{\left(1 + \left(-\log \left(\frac{1}{y}\right)\right)\right)} - \log \left(x - 1\right) \]
      4. log-rec98.7%

        \[\leadsto \left(1 + \left(-\color{blue}{\left(-\log y\right)}\right)\right) - \log \left(x - 1\right) \]
      5. remove-double-neg98.7%

        \[\leadsto \left(1 + \color{blue}{\log y}\right) - \log \left(x - 1\right) \]
      6. sub-neg98.7%

        \[\leadsto \left(1 + \log y\right) - \log \color{blue}{\left(x + \left(-1\right)\right)} \]
      7. metadata-eval98.7%

        \[\leadsto \left(1 + \log y\right) - \log \left(x + \color{blue}{-1}\right) \]
    7. Simplified98.7%

      \[\leadsto \color{blue}{\left(1 + \log y\right) - \log \left(x + -1\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -4200000000000:\\ \;\;\;\;1 - \left(\mathsf{log1p}\left(-x\right) + \log \left(\frac{-1}{y}\right)\right)\\ \mathbf{elif}\;y \leq 3.1 \cdot 10^{+15}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 + \log y\right) - \log \left(-1 + x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.7% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -400000:\\ \;\;\;\;\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 3.2 \cdot 10^{+18}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 + \log y\right) - \log \left(-1 + x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -400000.0)
   (- (+ (/ -1.0 y) (- 1.0 (log1p (- x)))) (log (/ -1.0 y)))
   (if (<= y 3.2e+18)
     (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
     (- (+ 1.0 (log y)) (log (+ -1.0 x))))))
double code(double x, double y) {
	double tmp;
	if (y <= -400000.0) {
		tmp = ((-1.0 / y) + (1.0 - log1p(-x))) - log((-1.0 / y));
	} else if (y <= 3.2e+18) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 + log(y)) - log((-1.0 + x));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -400000.0) {
		tmp = ((-1.0 / y) + (1.0 - Math.log1p(-x))) - Math.log((-1.0 / y));
	} else if (y <= 3.2e+18) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 + Math.log(y)) - Math.log((-1.0 + x));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -400000.0:
		tmp = ((-1.0 / y) + (1.0 - math.log1p(-x))) - math.log((-1.0 / y))
	elif y <= 3.2e+18:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = (1.0 + math.log(y)) - math.log((-1.0 + x))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -400000.0)
		tmp = Float64(Float64(Float64(-1.0 / y) + Float64(1.0 - log1p(Float64(-x)))) - log(Float64(-1.0 / y)));
	elseif (y <= 3.2e+18)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = Float64(Float64(1.0 + log(y)) - log(Float64(-1.0 + x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -400000.0], N[(N[(N[(-1.0 / y), $MachinePrecision] + N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 3.2e+18], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(1.0 + N[Log[y], $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 + x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -400000:\\
\;\;\;\;\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)\\

\mathbf{elif}\;y \leq 3.2 \cdot 10^{+18}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

\mathbf{else}:\\
\;\;\;\;\left(1 + \log y\right) - \log \left(-1 + x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -4e5

    1. Initial program 24.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg24.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define24.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac224.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub024.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-24.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval24.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative24.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified24.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.5%

      \[\leadsto \color{blue}{\left(1 + -1 \cdot \frac{\frac{x}{x - 1} - \frac{1}{x - 1}}{y}\right) - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Simplified99.5%

      \[\leadsto \color{blue}{\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]

    if -4e5 < y < 3.2e18

    1. Initial program 99.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define100.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac2100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub0100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing

    if 3.2e18 < y

    1. Initial program 66.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg66.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define66.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac266.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub066.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified66.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 98.7%

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. +-commutative98.7%

        \[\leadsto 1 - \color{blue}{\left(\log \left(\frac{1}{y}\right) + \log \left(x - 1\right)\right)} \]
      2. associate--r+98.7%

        \[\leadsto \color{blue}{\left(1 - \log \left(\frac{1}{y}\right)\right) - \log \left(x - 1\right)} \]
      3. sub-neg98.7%

        \[\leadsto \color{blue}{\left(1 + \left(-\log \left(\frac{1}{y}\right)\right)\right)} - \log \left(x - 1\right) \]
      4. log-rec98.7%

        \[\leadsto \left(1 + \left(-\color{blue}{\left(-\log y\right)}\right)\right) - \log \left(x - 1\right) \]
      5. remove-double-neg98.7%

        \[\leadsto \left(1 + \color{blue}{\log y}\right) - \log \left(x - 1\right) \]
      6. sub-neg98.7%

        \[\leadsto \left(1 + \log y\right) - \log \color{blue}{\left(x + \left(-1\right)\right)} \]
      7. metadata-eval98.7%

        \[\leadsto \left(1 + \log y\right) - \log \left(x + \color{blue}{-1}\right) \]
    7. Simplified98.7%

      \[\leadsto \color{blue}{\left(1 + \log y\right) - \log \left(x + -1\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -400000:\\ \;\;\;\;\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 3.2 \cdot 10^{+18}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 + \log y\right) - \log \left(-1 + x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 73.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{x - y}{1 - y} \leq 1:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{-1}{y} + 1\right) - \log \left(\frac{-1}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (/ (- x y) (- 1.0 y)) 1.0)
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
   (- (+ (/ -1.0 y) 1.0) (log (/ -1.0 y)))))
double code(double x, double y) {
	double tmp;
	if (((x - y) / (1.0 - y)) <= 1.0) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = ((-1.0 / y) + 1.0) - log((-1.0 / y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (((x - y) / (1.0 - y)) <= 1.0) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = ((-1.0 / y) + 1.0) - Math.log((-1.0 / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if ((x - y) / (1.0 - y)) <= 1.0:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = ((-1.0 / y) + 1.0) - math.log((-1.0 / y))
	return tmp
function code(x, y)
	tmp = 0.0
	if (Float64(Float64(x - y) / Float64(1.0 - y)) <= 1.0)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = Float64(Float64(Float64(-1.0 / y) + 1.0) - log(Float64(-1.0 / y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[N[(N[(x - y), $MachinePrecision] / N[(1.0 - y), $MachinePrecision]), $MachinePrecision], 1.0], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(N[(-1.0 / y), $MachinePrecision] + 1.0), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{x - y}{1 - y} \leq 1:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\frac{-1}{y} + 1\right) - \log \left(\frac{-1}{y}\right)\\


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

    1. Initial program 75.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg75.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define75.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac275.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub075.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-75.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval75.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative75.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified75.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing

    if 1 < (/.f64 (-.f64 x y) (-.f64 #s(literal 1 binary64) y))

    1. Initial program 75.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg75.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define75.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac275.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub075.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-75.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval75.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative75.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified75.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 28.3%

      \[\leadsto \color{blue}{\left(1 + -1 \cdot \frac{\frac{x}{x - 1} - \frac{1}{x - 1}}{y}\right) - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Simplified28.3%

      \[\leadsto \color{blue}{\left(\frac{-1}{y} + \left(1 - \mathsf{log1p}\left(-x\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    7. Taylor expanded in x around 0 18.7%

      \[\leadsto \color{blue}{\left(1 - \frac{1}{y}\right)} - \log \left(\frac{-1}{y}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification75.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x - y}{1 - y} \leq 1:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{-1}{y} + 1\right) - \log \left(\frac{-1}{y}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 73.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -2.7:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1 + \frac{x}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -2.7)
   (- 1.0 (log1p (/ x y)))
   (if (<= y 1.0)
     (- (- 1.0 y) (log1p (- x)))
     (- 1.0 (log1p (+ -1.0 (/ x y)))))))
double code(double x, double y) {
	double tmp;
	if (y <= -2.7) {
		tmp = 1.0 - log1p((x / y));
	} else if (y <= 1.0) {
		tmp = (1.0 - y) - log1p(-x);
	} else {
		tmp = 1.0 - log1p((-1.0 + (x / y)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -2.7) {
		tmp = 1.0 - Math.log1p((x / y));
	} else if (y <= 1.0) {
		tmp = (1.0 - y) - Math.log1p(-x);
	} else {
		tmp = 1.0 - Math.log1p((-1.0 + (x / y)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -2.7:
		tmp = 1.0 - math.log1p((x / y))
	elif y <= 1.0:
		tmp = (1.0 - y) - math.log1p(-x)
	else:
		tmp = 1.0 - math.log1p((-1.0 + (x / y)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -2.7)
		tmp = Float64(1.0 - log1p(Float64(x / y)));
	elseif (y <= 1.0)
		tmp = Float64(Float64(1.0 - y) - log1p(Float64(-x)));
	else
		tmp = Float64(1.0 - log1p(Float64(-1.0 + Float64(x / y))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -2.7], N[(1.0 - N[Log[1 + N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.0], N[(N[(1.0 - y), $MachinePrecision] - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(-1.0 + N[(x / y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -2.7:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\

\mathbf{elif}\;y \leq 1:\\
\;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\

\mathbf{else}:\\
\;\;\;\;1 - \mathsf{log1p}\left(-1 + \frac{x}{y}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -2.7000000000000002

    1. Initial program 25.5%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.5%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative25.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.5%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 32.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 31.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y}}\right) \]

    if -2.7000000000000002 < y < 1

    1. Initial program 99.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define100.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac2100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub0100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 97.4%

      \[\leadsto \color{blue}{\left(1 + y \cdot \left(\frac{x}{1 + -1 \cdot x} - \frac{1}{1 + -1 \cdot x}\right)\right) - \log \left(1 + -1 \cdot x\right)} \]
    6. Simplified97.5%

      \[\leadsto \color{blue}{\left(1 - y\right) - \mathsf{log1p}\left(-x\right)} \]

    if 1 < y

    1. Initial program 66.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg66.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define66.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac266.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub066.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative66.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified66.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. clear-num66.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{\frac{y + -1}{x - y}}}\right) \]
      2. associate-/r/67.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    6. Applied egg-rr67.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    7. Taylor expanded in y around inf 67.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y}} \cdot \left(x - y\right)\right) \]
    8. Taylor expanded in y around inf 66.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - 1}\right) \]
  3. Recombined 3 regimes into one program.
  4. Final simplification75.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -2.7:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1 + \frac{x}{y}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 73.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -2.05 \lor \neg \left(y \leq 1\right):\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (or (<= y -2.05) (not (<= y 1.0)))
   (- 1.0 (log1p (/ x y)))
   (- (- 1.0 y) (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if ((y <= -2.05) || !(y <= 1.0)) {
		tmp = 1.0 - log1p((x / y));
	} else {
		tmp = (1.0 - y) - log1p(-x);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if ((y <= -2.05) || !(y <= 1.0)) {
		tmp = 1.0 - Math.log1p((x / y));
	} else {
		tmp = (1.0 - y) - Math.log1p(-x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if (y <= -2.05) or not (y <= 1.0):
		tmp = 1.0 - math.log1p((x / y))
	else:
		tmp = (1.0 - y) - math.log1p(-x)
	return tmp
function code(x, y)
	tmp = 0.0
	if ((y <= -2.05) || !(y <= 1.0))
		tmp = Float64(1.0 - log1p(Float64(x / y)));
	else
		tmp = Float64(Float64(1.0 - y) - log1p(Float64(-x)));
	end
	return tmp
end
code[x_, y_] := If[Or[LessEqual[y, -2.05], N[Not[LessEqual[y, 1.0]], $MachinePrecision]], N[(1.0 - N[Log[1 + N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(1.0 - y), $MachinePrecision] - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -2.05 \lor \neg \left(y \leq 1\right):\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\

\mathbf{else}:\\
\;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -2.0499999999999998 or 1 < y

    1. Initial program 37.8%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg37.8%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define37.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac237.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub037.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-37.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval37.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative37.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified37.8%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 41.4%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 40.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y}}\right) \]

    if -2.0499999999999998 < y < 1

    1. Initial program 99.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define100.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac2100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub0100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 97.4%

      \[\leadsto \color{blue}{\left(1 + y \cdot \left(\frac{x}{1 + -1 \cdot x} - \frac{1}{1 + -1 \cdot x}\right)\right) - \log \left(1 + -1 \cdot x\right)} \]
    6. Simplified97.5%

      \[\leadsto \color{blue}{\left(1 - y\right) - \mathsf{log1p}\left(-x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification75.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -2.05 \lor \neg \left(y \leq 1\right):\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 73.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1 \lor \neg \left(y \leq 0.0033\right):\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (or (<= y -1.0) (not (<= y 0.0033)))
   (- 1.0 (log1p (/ x y)))
   (- 1.0 (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if ((y <= -1.0) || !(y <= 0.0033)) {
		tmp = 1.0 - log1p((x / y));
	} else {
		tmp = 1.0 - log1p(-x);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if ((y <= -1.0) || !(y <= 0.0033)) {
		tmp = 1.0 - Math.log1p((x / y));
	} else {
		tmp = 1.0 - Math.log1p(-x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if (y <= -1.0) or not (y <= 0.0033):
		tmp = 1.0 - math.log1p((x / y))
	else:
		tmp = 1.0 - math.log1p(-x)
	return tmp
function code(x, y)
	tmp = 0.0
	if ((y <= -1.0) || !(y <= 0.0033))
		tmp = Float64(1.0 - log1p(Float64(x / y)));
	else
		tmp = Float64(1.0 - log1p(Float64(-x)));
	end
	return tmp
end
code[x_, y_] := If[Or[LessEqual[y, -1.0], N[Not[LessEqual[y, 0.0033]], $MachinePrecision]], N[(1.0 - N[Log[1 + N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1 \lor \neg \left(y \leq 0.0033\right):\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\

\mathbf{else}:\\
\;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -1 or 0.0033 < y

    1. Initial program 38.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg38.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define38.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac238.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub038.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-38.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval38.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative38.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified38.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 41.3%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 40.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y}}\right) \]

    if -1 < y < 0.0033

    1. Initial program 99.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define100.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac2100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub0100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 96.7%

      \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
    6. Step-by-step derivation
      1. log1p-define96.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
      2. mul-1-neg96.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
    7. Simplified96.7%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification74.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1 \lor \neg \left(y \leq 0.0033\right):\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 75.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -9 \cdot 10^{+15}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -9e+15)
   (- 1.0 (log1p (/ x y)))
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))))
double code(double x, double y) {
	double tmp;
	if (y <= -9e+15) {
		tmp = 1.0 - log1p((x / y));
	} else {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -9e+15) {
		tmp = 1.0 - Math.log1p((x / y));
	} else {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -9e+15:
		tmp = 1.0 - math.log1p((x / y))
	else:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -9e+15)
		tmp = Float64(1.0 - log1p(Float64(x / y)));
	else
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -9e+15], N[(1.0 - N[Log[1 + N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -9 \cdot 10^{+15}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\

\mathbf{else}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -9e15

    1. Initial program 22.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg22.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define22.6%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac222.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub022.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-22.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval22.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative22.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified22.6%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 30.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 30.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y}}\right) \]

    if -9e15 < y

    1. Initial program 94.5%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg94.5%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define94.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac294.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub094.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-94.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval94.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative94.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified94.5%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification77.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -9 \cdot 10^{+15}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 73.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right) \end{array} \]
(FPCore (x y) :precision binary64 (- 1.0 (log1p (/ x (+ y -1.0)))))
double code(double x, double y) {
	return 1.0 - log1p((x / (y + -1.0)));
}
public static double code(double x, double y) {
	return 1.0 - Math.log1p((x / (y + -1.0)));
}
def code(x, y):
	return 1.0 - math.log1p((x / (y + -1.0)))
function code(x, y)
	return Float64(1.0 - log1p(Float64(x / Float64(y + -1.0))))
end
code[x_, y_] := N[(1.0 - N[Log[1 + N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)
\end{array}
Derivation
  1. Initial program 75.7%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg75.7%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define75.7%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac275.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub075.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified75.7%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 74.8%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Final simplification74.8%

    \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right) \]
  7. Add Preprocessing

Alternative 10: 63.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ 1 - \mathsf{log1p}\left(-x\right) \end{array} \]
(FPCore (x y) :precision binary64 (- 1.0 (log1p (- x))))
double code(double x, double y) {
	return 1.0 - log1p(-x);
}
public static double code(double x, double y) {
	return 1.0 - Math.log1p(-x);
}
def code(x, y):
	return 1.0 - math.log1p(-x)
function code(x, y)
	return Float64(1.0 - log1p(Float64(-x)))
end
code[x_, y_] := N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - \mathsf{log1p}\left(-x\right)
\end{array}
Derivation
  1. Initial program 75.7%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg75.7%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define75.7%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac275.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub075.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified75.7%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 62.3%

    \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define62.3%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg62.3%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified62.3%

    \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  8. Final simplification62.3%

    \[\leadsto 1 - \mathsf{log1p}\left(-x\right) \]
  9. Add Preprocessing

Alternative 11: 45.1% accurate, 15.9× speedup?

\[\begin{array}{l} \\ 1 - \frac{x}{y + -1} \end{array} \]
(FPCore (x y) :precision binary64 (- 1.0 (/ x (+ y -1.0))))
double code(double x, double y) {
	return 1.0 - (x / (y + -1.0));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = 1.0d0 - (x / (y + (-1.0d0)))
end function
public static double code(double x, double y) {
	return 1.0 - (x / (y + -1.0));
}
def code(x, y):
	return 1.0 - (x / (y + -1.0))
function code(x, y)
	return Float64(1.0 - Float64(x / Float64(y + -1.0)))
end
function tmp = code(x, y)
	tmp = 1.0 - (x / (y + -1.0));
end
code[x_, y_] := N[(1.0 - N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - \frac{x}{y + -1}
\end{array}
Derivation
  1. Initial program 75.7%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg75.7%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define75.7%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac275.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub075.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified75.7%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 74.8%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 46.5%

    \[\leadsto \color{blue}{1 + -1 \cdot \frac{x}{y - 1}} \]
  7. Step-by-step derivation
    1. mul-1-neg46.5%

      \[\leadsto 1 + \color{blue}{\left(-\frac{x}{y - 1}\right)} \]
    2. sub-neg46.5%

      \[\leadsto 1 + \left(-\frac{x}{\color{blue}{y + \left(-1\right)}}\right) \]
    3. metadata-eval46.5%

      \[\leadsto 1 + \left(-\frac{x}{y + \color{blue}{-1}}\right) \]
    4. unsub-neg46.5%

      \[\leadsto \color{blue}{1 - \frac{x}{y + -1}} \]
    5. +-commutative46.5%

      \[\leadsto 1 - \frac{x}{\color{blue}{-1 + y}} \]
  8. Simplified46.5%

    \[\leadsto \color{blue}{1 - \frac{x}{-1 + y}} \]
  9. Final simplification46.5%

    \[\leadsto 1 - \frac{x}{y + -1} \]
  10. Add Preprocessing

Alternative 12: 43.7% accurate, 37.0× speedup?

\[\begin{array}{l} \\ 1 + x \end{array} \]
(FPCore (x y) :precision binary64 (+ 1.0 x))
double code(double x, double y) {
	return 1.0 + x;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = 1.0d0 + x
end function
public static double code(double x, double y) {
	return 1.0 + x;
}
def code(x, y):
	return 1.0 + x
function code(x, y)
	return Float64(1.0 + x)
end
function tmp = code(x, y)
	tmp = 1.0 + x;
end
code[x_, y_] := N[(1.0 + x), $MachinePrecision]
\begin{array}{l}

\\
1 + x
\end{array}
Derivation
  1. Initial program 75.7%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg75.7%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define75.7%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac275.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub075.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified75.7%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 62.3%

    \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define62.3%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg62.3%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified62.3%

    \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  8. Taylor expanded in x around 0 45.1%

    \[\leadsto \color{blue}{1 + x} \]
  9. Final simplification45.1%

    \[\leadsto 1 + x \]
  10. Add Preprocessing

Alternative 13: 43.4% accurate, 111.0× speedup?

\[\begin{array}{l} \\ 1 \end{array} \]
(FPCore (x y) :precision binary64 1.0)
double code(double x, double y) {
	return 1.0;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = 1.0d0
end function
public static double code(double x, double y) {
	return 1.0;
}
def code(x, y):
	return 1.0
function code(x, y)
	return 1.0
end
function tmp = code(x, y)
	tmp = 1.0;
end
code[x_, y_] := 1.0
\begin{array}{l}

\\
1
\end{array}
Derivation
  1. Initial program 75.7%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg75.7%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define75.7%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac275.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub075.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative75.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified75.7%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 62.3%

    \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define62.3%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg62.3%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified62.3%

    \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  8. Taylor expanded in x around 0 44.6%

    \[\leadsto \color{blue}{1} \]
  9. Final simplification44.6%

    \[\leadsto 1 \]
  10. Add Preprocessing

Developer target: 99.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 1 - \log \left(\frac{x}{y \cdot y} - \left(\frac{1}{y} - \frac{x}{y}\right)\right)\\ \mathbf{if}\;y < -81284752.61947241:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;y < 3.0094271212461764 \cdot 10^{+25}:\\ \;\;\;\;\log \left(\frac{e^{1}}{1 - \frac{x - y}{1 - y}}\right)\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (- 1.0 (log (- (/ x (* y y)) (- (/ 1.0 y) (/ x y)))))))
   (if (< y -81284752.61947241)
     t_0
     (if (< y 3.0094271212461764e+25)
       (log (/ (exp 1.0) (- 1.0 (/ (- x y) (- 1.0 y)))))
       t_0))))
double code(double x, double y) {
	double t_0 = 1.0 - log(((x / (y * y)) - ((1.0 / y) - (x / y))));
	double tmp;
	if (y < -81284752.61947241) {
		tmp = t_0;
	} else if (y < 3.0094271212461764e+25) {
		tmp = log((exp(1.0) / (1.0 - ((x - y) / (1.0 - y)))));
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: t_0
    real(8) :: tmp
    t_0 = 1.0d0 - log(((x / (y * y)) - ((1.0d0 / y) - (x / y))))
    if (y < (-81284752.61947241d0)) then
        tmp = t_0
    else if (y < 3.0094271212461764d+25) then
        tmp = log((exp(1.0d0) / (1.0d0 - ((x - y) / (1.0d0 - y)))))
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double t_0 = 1.0 - Math.log(((x / (y * y)) - ((1.0 / y) - (x / y))));
	double tmp;
	if (y < -81284752.61947241) {
		tmp = t_0;
	} else if (y < 3.0094271212461764e+25) {
		tmp = Math.log((Math.exp(1.0) / (1.0 - ((x - y) / (1.0 - y)))));
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, y):
	t_0 = 1.0 - math.log(((x / (y * y)) - ((1.0 / y) - (x / y))))
	tmp = 0
	if y < -81284752.61947241:
		tmp = t_0
	elif y < 3.0094271212461764e+25:
		tmp = math.log((math.exp(1.0) / (1.0 - ((x - y) / (1.0 - y)))))
	else:
		tmp = t_0
	return tmp
function code(x, y)
	t_0 = Float64(1.0 - log(Float64(Float64(x / Float64(y * y)) - Float64(Float64(1.0 / y) - Float64(x / y)))))
	tmp = 0.0
	if (y < -81284752.61947241)
		tmp = t_0;
	elseif (y < 3.0094271212461764e+25)
		tmp = log(Float64(exp(1.0) / Float64(1.0 - Float64(Float64(x - y) / Float64(1.0 - y)))));
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, y)
	t_0 = 1.0 - log(((x / (y * y)) - ((1.0 / y) - (x / y))));
	tmp = 0.0;
	if (y < -81284752.61947241)
		tmp = t_0;
	elseif (y < 3.0094271212461764e+25)
		tmp = log((exp(1.0) / (1.0 - ((x - y) / (1.0 - y)))));
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, y_] := Block[{t$95$0 = N[(1.0 - N[Log[N[(N[(x / N[(y * y), $MachinePrecision]), $MachinePrecision] - N[(N[(1.0 / y), $MachinePrecision] - N[(x / y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, If[Less[y, -81284752.61947241], t$95$0, If[Less[y, 3.0094271212461764e+25], N[Log[N[(N[Exp[1.0], $MachinePrecision] / N[(1.0 - N[(N[(x - y), $MachinePrecision] / N[(1.0 - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 1 - \log \left(\frac{x}{y \cdot y} - \left(\frac{1}{y} - \frac{x}{y}\right)\right)\\
\mathbf{if}\;y < -81284752.61947241:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;y < 3.0094271212461764 \cdot 10^{+25}:\\
\;\;\;\;\log \left(\frac{e^{1}}{1 - \frac{x - y}{1 - y}}\right)\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024066 
(FPCore (x y)
  :name "Numeric.SpecFunctions:invIncompleteGamma from math-functions-0.1.5.2, B"
  :precision binary64

  :alt
  (if (< y -81284752.61947241) (- 1.0 (log (- (/ x (* y y)) (- (/ 1.0 y) (/ x y))))) (if (< y 3.0094271212461764e+25) (log (/ (exp 1.0) (- 1.0 (/ (- x y) (- 1.0 y))))) (- 1.0 (log (- (/ x (* y y)) (- (/ 1.0 y) (/ x y)))))))

  (- 1.0 (log (- 1.0 (/ (- x y) (- 1.0 y))))))