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

Percentage Accurate: 71.8% → 99.9%
Time: 12.7s
Alternatives: 10
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 10 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: 71.8% 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: 99.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \log \left(y \cdot \left(\frac{e}{y \cdot \left(1 - x\right)} + \frac{e}{x + -1}\right)\right) \end{array} \]
(FPCore (x y)
 :precision binary64
 (log (* y (+ (/ E (* y (- 1.0 x))) (/ E (+ x -1.0))))))
double code(double x, double y) {
	return log((y * ((((double) M_E) / (y * (1.0 - x))) + (((double) M_E) / (x + -1.0)))));
}
public static double code(double x, double y) {
	return Math.log((y * ((Math.E / (y * (1.0 - x))) + (Math.E / (x + -1.0)))));
}
def code(x, y):
	return math.log((y * ((math.e / (y * (1.0 - x))) + (math.e / (x + -1.0)))))
function code(x, y)
	return log(Float64(y * Float64(Float64(exp(1) / Float64(y * Float64(1.0 - x))) + Float64(exp(1) / Float64(x + -1.0)))))
end
function tmp = code(x, y)
	tmp = log((y * ((2.71828182845904523536 / (y * (1.0 - x))) + (2.71828182845904523536 / (x + -1.0)))));
end
code[x_, y_] := N[Log[N[(y * N[(N[(E / N[(y * N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(E / N[(x + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(y \cdot \left(\frac{e}{y \cdot \left(1 - x\right)} + \frac{e}{x + -1}\right)\right)
\end{array}
Derivation
  1. Initial program 70.5%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg70.5%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define70.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac270.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub070.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified70.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around -inf 34.8%

    \[\leadsto 1 - \color{blue}{\left(\log \left(-1 \cdot \left(x - 1\right)\right) + \left(\log \left(\frac{-1}{y}\right) + -1 \cdot \frac{\frac{1}{x - 1} - \frac{x}{x - 1}}{y}\right)\right)} \]
  6. Simplified34.8%

    \[\leadsto 1 - \color{blue}{\left(\mathsf{log1p}\left(-x\right) + \left(\frac{1}{y} + \log \left(\frac{-1}{y}\right)\right)\right)} \]
  7. Step-by-step derivation
    1. associate--r+34.8%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \left(\frac{1}{y} + \log \left(\frac{-1}{y}\right)\right)} \]
    2. add-log-exp34.4%

      \[\leadsto \color{blue}{\log \left(e^{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \left(\frac{1}{y} + \log \left(\frac{-1}{y}\right)\right)}\right)} \]
    3. exp-diff34.4%

      \[\leadsto \log \color{blue}{\left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{e^{\frac{1}{y} + \log \left(\frac{-1}{y}\right)}}\right)} \]
    4. +-commutative34.4%

      \[\leadsto \log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{e^{\color{blue}{\log \left(\frac{-1}{y}\right) + \frac{1}{y}}}}\right) \]
    5. exp-sum34.4%

      \[\leadsto \log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{\color{blue}{e^{\log \left(\frac{-1}{y}\right)} \cdot e^{\frac{1}{y}}}}\right) \]
    6. add-exp-log34.8%

      \[\leadsto \log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{\color{blue}{\frac{-1}{y}} \cdot e^{\frac{1}{y}}}\right) \]
  8. Applied egg-rr34.8%

    \[\leadsto \color{blue}{\log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right)} \]
  9. Step-by-step derivation
    1. exp-diff34.8%

      \[\leadsto \log \left(\frac{\color{blue}{\frac{e^{1}}{e^{\mathsf{log1p}\left(-x\right)}}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    2. exp-1-e34.8%

      \[\leadsto \log \left(\frac{\frac{\color{blue}{e}}{e^{\mathsf{log1p}\left(-x\right)}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    3. log1p-undefine34.8%

      \[\leadsto \log \left(\frac{\frac{e}{e^{\color{blue}{\log \left(1 + \left(-x\right)\right)}}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    4. neg-mul-134.8%

      \[\leadsto \log \left(\frac{\frac{e}{e^{\log \left(1 + \color{blue}{-1 \cdot x}\right)}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    5. rem-exp-log45.6%

      \[\leadsto \log \left(\frac{\frac{e}{\color{blue}{1 + -1 \cdot x}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    6. neg-mul-145.6%

      \[\leadsto \log \left(\frac{\frac{e}{1 + \color{blue}{\left(-x\right)}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    7. sub-neg45.6%

      \[\leadsto \log \left(\frac{\frac{e}{\color{blue}{1 - x}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
    8. associate-*l/45.6%

      \[\leadsto \log \left(\frac{\frac{e}{1 - x}}{\color{blue}{\frac{-1 \cdot e^{\frac{1}{y}}}{y}}}\right) \]
    9. mul-1-neg45.6%

      \[\leadsto \log \left(\frac{\frac{e}{1 - x}}{\frac{\color{blue}{-e^{\frac{1}{y}}}}{y}}\right) \]
  10. Simplified45.6%

    \[\leadsto \color{blue}{\log \left(\frac{\frac{e}{1 - x}}{\frac{-e^{\frac{1}{y}}}{y}}\right)} \]
  11. Taylor expanded in y around inf 99.9%

    \[\leadsto \log \color{blue}{\left(y \cdot \left(-1 \cdot \frac{e}{1 - x} + \frac{e}{y \cdot \left(1 - x\right)}\right)\right)} \]
  12. Step-by-step derivation
    1. +-commutative99.9%

      \[\leadsto \log \left(y \cdot \color{blue}{\left(\frac{e}{y \cdot \left(1 - x\right)} + -1 \cdot \frac{e}{1 - x}\right)}\right) \]
    2. neg-mul-199.9%

      \[\leadsto \log \left(y \cdot \left(\frac{e}{y \cdot \left(1 - x\right)} + \color{blue}{\left(-\frac{e}{1 - x}\right)}\right)\right) \]
    3. unsub-neg99.9%

      \[\leadsto \log \left(y \cdot \color{blue}{\left(\frac{e}{y \cdot \left(1 - x\right)} - \frac{e}{1 - x}\right)}\right) \]
  13. Simplified99.9%

    \[\leadsto \log \color{blue}{\left(y \cdot \left(\frac{e}{y \cdot \left(1 - x\right)} - \frac{e}{1 - x}\right)\right)} \]
  14. Final simplification99.9%

    \[\leadsto \log \left(y \cdot \left(\frac{e}{y \cdot \left(1 - x\right)} + \frac{e}{x + -1}\right)\right) \]
  15. Add Preprocessing

Alternative 2: 99.8% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{x - y}{1 - y} \leq 0.99998:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (/ (- x y) (- 1.0 y)) 0.99998)
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
   (log (* E (/ y (+ x -1.0))))))
double code(double x, double y) {
	double tmp;
	if (((x - y) / (1.0 - y)) <= 0.99998) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = log((((double) M_E) * (y / (x + -1.0))));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (((x - y) / (1.0 - y)) <= 0.99998) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = Math.log((Math.E * (y / (x + -1.0))));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if ((x - y) / (1.0 - y)) <= 0.99998:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = math.log((math.e * (y / (x + -1.0))))
	return tmp
function code(x, y)
	tmp = 0.0
	if (Float64(Float64(x - y) / Float64(1.0 - y)) <= 0.99998)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = log(Float64(exp(1) * Float64(y / Float64(x + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[N[(N[(x - y), $MachinePrecision] / N[(1.0 - y), $MachinePrecision]), $MachinePrecision], 0.99998], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Log[N[(E * N[(y / N[(x + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{x - y}{1 - y} \leq 0.99998:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (-.f64 x y) (-.f64 #s(literal 1 binary64) y)) < 0.99997999999999998

    1. Initial program 99.8%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg99.8%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define99.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac299.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub099.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-99.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval99.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative99.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified99.9%

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

    if 0.99997999999999998 < (/.f64 (-.f64 x y) (-.f64 #s(literal 1 binary64) y))

    1. Initial program 6.1%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg6.1%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define6.1%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac26.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub06.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified6.1%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 6.1%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval6.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified6.1%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Step-by-step derivation
      1. *-un-lft-identity6.1%

        \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(\frac{x + -1}{y} + -1\right)} \]
      2. +-commutative6.1%

        \[\leadsto 1 - 1 \cdot \mathsf{log1p}\left(\color{blue}{-1 + \frac{x + -1}{y}}\right) \]
    9. Applied egg-rr6.1%

      \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
    10. Step-by-step derivation
      1. *-lft-identity6.1%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
      2. log1p-define6.1%

        \[\leadsto 1 - \color{blue}{\log \left(1 + \left(-1 + \frac{x + -1}{y}\right)\right)} \]
      3. associate-+r+99.2%

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

        \[\leadsto 1 - \log \left(\color{blue}{0} + \frac{x + -1}{y}\right) \]
      5. +-lft-identity99.2%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{x + -1}{y}\right)} \]
      6. +-commutative99.2%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1 + x}}{y}\right) \]
    11. Simplified99.2%

      \[\leadsto 1 - \color{blue}{\log \left(\frac{-1 + x}{y}\right)} \]
    12. Step-by-step derivation
      1. add-log-exp99.2%

        \[\leadsto \color{blue}{\log \left(e^{1 - \log \left(\frac{-1 + x}{y}\right)}\right)} \]
      2. sub-neg99.2%

        \[\leadsto \log \left(e^{\color{blue}{1 + \left(-\log \left(\frac{-1 + x}{y}\right)\right)}}\right) \]
      3. exp-sum99.2%

        \[\leadsto \log \color{blue}{\left(e^{1} \cdot e^{-\log \left(\frac{-1 + x}{y}\right)}\right)} \]
      4. e-exp-199.2%

        \[\leadsto \log \left(\color{blue}{e} \cdot e^{-\log \left(\frac{-1 + x}{y}\right)}\right) \]
      5. neg-log99.2%

        \[\leadsto \log \left(e \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1 + x}{y}}\right)}}\right) \]
      6. clear-num99.2%

        \[\leadsto \log \left(e \cdot e^{\log \color{blue}{\left(\frac{y}{-1 + x}\right)}}\right) \]
      7. add-exp-log99.2%

        \[\leadsto \log \left(e \cdot \color{blue}{\frac{y}{-1 + x}}\right) \]
      8. +-commutative99.2%

        \[\leadsto \log \left(e \cdot \frac{y}{\color{blue}{x + -1}}\right) \]
    13. Applied egg-rr99.2%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{x - y}{1 - y} \leq 0.99998:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 98.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.75 \lor \neg \left(y \leq 1\right):\\ \;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (or (<= y -1.75) (not (<= y 1.0)))
   (log (* E (/ y (+ x -1.0))))
   (- (- 1.0 y) (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if ((y <= -1.75) || !(y <= 1.0)) {
		tmp = log((((double) M_E) * (y / (x + -1.0))));
	} else {
		tmp = (1.0 - y) - log1p(-x);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if ((y <= -1.75) || !(y <= 1.0)) {
		tmp = Math.log((Math.E * (y / (x + -1.0))));
	} else {
		tmp = (1.0 - y) - Math.log1p(-x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if (y <= -1.75) or not (y <= 1.0):
		tmp = math.log((math.e * (y / (x + -1.0))))
	else:
		tmp = (1.0 - y) - math.log1p(-x)
	return tmp
function code(x, y)
	tmp = 0.0
	if ((y <= -1.75) || !(y <= 1.0))
		tmp = log(Float64(exp(1) * Float64(y / Float64(x + -1.0))));
	else
		tmp = Float64(Float64(1.0 - y) - log1p(Float64(-x)));
	end
	return tmp
end
code[x_, y_] := If[Or[LessEqual[y, -1.75], N[Not[LessEqual[y, 1.0]], $MachinePrecision]], N[Log[N[(E * N[(y / N[(x + -1.0), $MachinePrecision]), $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 -1.75 \lor \neg \left(y \leq 1\right):\\
\;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\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 < -1.75 or 1 < y

    1. Initial program 35.1%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg35.1%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define35.1%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac235.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub035.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-35.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval35.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative35.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified35.1%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 32.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval32.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified32.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Step-by-step derivation
      1. *-un-lft-identity32.5%

        \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(\frac{x + -1}{y} + -1\right)} \]
      2. +-commutative32.5%

        \[\leadsto 1 - 1 \cdot \mathsf{log1p}\left(\color{blue}{-1 + \frac{x + -1}{y}}\right) \]
    9. Applied egg-rr32.5%

      \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
    10. Step-by-step derivation
      1. *-lft-identity32.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
      2. log1p-define32.5%

        \[\leadsto 1 - \color{blue}{\log \left(1 + \left(-1 + \frac{x + -1}{y}\right)\right)} \]
      3. associate-+r+96.7%

        \[\leadsto 1 - \log \color{blue}{\left(\left(1 + -1\right) + \frac{x + -1}{y}\right)} \]
      4. metadata-eval96.7%

        \[\leadsto 1 - \log \left(\color{blue}{0} + \frac{x + -1}{y}\right) \]
      5. +-lft-identity96.7%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{x + -1}{y}\right)} \]
      6. +-commutative96.7%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1 + x}}{y}\right) \]
    11. Simplified96.7%

      \[\leadsto 1 - \color{blue}{\log \left(\frac{-1 + x}{y}\right)} \]
    12. Step-by-step derivation
      1. add-log-exp96.7%

        \[\leadsto \color{blue}{\log \left(e^{1 - \log \left(\frac{-1 + x}{y}\right)}\right)} \]
      2. sub-neg96.7%

        \[\leadsto \log \left(e^{\color{blue}{1 + \left(-\log \left(\frac{-1 + x}{y}\right)\right)}}\right) \]
      3. exp-sum96.7%

        \[\leadsto \log \color{blue}{\left(e^{1} \cdot e^{-\log \left(\frac{-1 + x}{y}\right)}\right)} \]
      4. e-exp-196.7%

        \[\leadsto \log \left(\color{blue}{e} \cdot e^{-\log \left(\frac{-1 + x}{y}\right)}\right) \]
      5. neg-log96.7%

        \[\leadsto \log \left(e \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1 + x}{y}}\right)}}\right) \]
      6. clear-num96.7%

        \[\leadsto \log \left(e \cdot e^{\log \color{blue}{\left(\frac{y}{-1 + x}\right)}}\right) \]
      7. add-exp-log96.7%

        \[\leadsto \log \left(e \cdot \color{blue}{\frac{y}{-1 + x}}\right) \]
      8. +-commutative96.7%

        \[\leadsto \log \left(e \cdot \frac{y}{\color{blue}{x + -1}}\right) \]
    13. Applied egg-rr96.7%

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

    if -1.75 < 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 98.4%

      \[\leadsto \color{blue}{\left(1 + y \cdot \left(\frac{x}{1 + -1 \cdot x} - \frac{1}{1 + -1 \cdot x}\right)\right) - \log \left(1 + -1 \cdot x\right)} \]
    6. Simplified98.4%

      \[\leadsto \color{blue}{\left(1 - y\right) - \mathsf{log1p}\left(-x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1.75 \lor \neg \left(y \leq 1\right):\\ \;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 98.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.85:\\ \;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1.85)
   (log (* E (/ y (+ x -1.0))))
   (if (<= y 1.0) (- (- 1.0 y) (log1p (- x))) (- 1.0 (log (/ (+ x -1.0) y))))))
double code(double x, double y) {
	double tmp;
	if (y <= -1.85) {
		tmp = log((((double) M_E) * (y / (x + -1.0))));
	} else if (y <= 1.0) {
		tmp = (1.0 - y) - log1p(-x);
	} else {
		tmp = 1.0 - log(((x + -1.0) / y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1.85) {
		tmp = Math.log((Math.E * (y / (x + -1.0))));
	} else if (y <= 1.0) {
		tmp = (1.0 - y) - Math.log1p(-x);
	} else {
		tmp = 1.0 - Math.log(((x + -1.0) / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1.85:
		tmp = math.log((math.e * (y / (x + -1.0))))
	elif y <= 1.0:
		tmp = (1.0 - y) - math.log1p(-x)
	else:
		tmp = 1.0 - math.log(((x + -1.0) / y))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1.85)
		tmp = log(Float64(exp(1) * Float64(y / Float64(x + -1.0))));
	elseif (y <= 1.0)
		tmp = Float64(Float64(1.0 - y) - log1p(Float64(-x)));
	else
		tmp = Float64(1.0 - log(Float64(Float64(x + -1.0) / y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1.85], N[Log[N[(E * N[(y / N[(x + -1.0), $MachinePrecision]), $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[N[(N[(x + -1.0), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.85:\\
\;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1.8500000000000001

    1. Initial program 25.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 22.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified22.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Step-by-step derivation
      1. *-un-lft-identity22.8%

        \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(\frac{x + -1}{y} + -1\right)} \]
      2. +-commutative22.8%

        \[\leadsto 1 - 1 \cdot \mathsf{log1p}\left(\color{blue}{-1 + \frac{x + -1}{y}}\right) \]
    9. Applied egg-rr22.8%

      \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
    10. Step-by-step derivation
      1. *-lft-identity22.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
      2. log1p-define22.8%

        \[\leadsto 1 - \color{blue}{\log \left(1 + \left(-1 + \frac{x + -1}{y}\right)\right)} \]
      3. associate-+r+96.4%

        \[\leadsto 1 - \log \color{blue}{\left(\left(1 + -1\right) + \frac{x + -1}{y}\right)} \]
      4. metadata-eval96.4%

        \[\leadsto 1 - \log \left(\color{blue}{0} + \frac{x + -1}{y}\right) \]
      5. +-lft-identity96.4%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{x + -1}{y}\right)} \]
      6. +-commutative96.4%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1 + x}}{y}\right) \]
    11. Simplified96.4%

      \[\leadsto 1 - \color{blue}{\log \left(\frac{-1 + x}{y}\right)} \]
    12. Step-by-step derivation
      1. add-log-exp96.4%

        \[\leadsto \color{blue}{\log \left(e^{1 - \log \left(\frac{-1 + x}{y}\right)}\right)} \]
      2. sub-neg96.4%

        \[\leadsto \log \left(e^{\color{blue}{1 + \left(-\log \left(\frac{-1 + x}{y}\right)\right)}}\right) \]
      3. exp-sum96.4%

        \[\leadsto \log \color{blue}{\left(e^{1} \cdot e^{-\log \left(\frac{-1 + x}{y}\right)}\right)} \]
      4. e-exp-196.4%

        \[\leadsto \log \left(\color{blue}{e} \cdot e^{-\log \left(\frac{-1 + x}{y}\right)}\right) \]
      5. neg-log96.4%

        \[\leadsto \log \left(e \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1 + x}{y}}\right)}}\right) \]
      6. clear-num96.4%

        \[\leadsto \log \left(e \cdot e^{\log \color{blue}{\left(\frac{y}{-1 + x}\right)}}\right) \]
      7. add-exp-log96.4%

        \[\leadsto \log \left(e \cdot \color{blue}{\frac{y}{-1 + x}}\right) \]
      8. +-commutative96.4%

        \[\leadsto \log \left(e \cdot \frac{y}{\color{blue}{x + -1}}\right) \]
    13. Applied egg-rr96.4%

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

    if -1.8500000000000001 < 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 98.4%

      \[\leadsto \color{blue}{\left(1 + y \cdot \left(\frac{x}{1 + -1 \cdot x} - \frac{1}{1 + -1 \cdot x}\right)\right) - \log \left(1 + -1 \cdot x\right)} \]
    6. Simplified98.4%

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

    if 1 < y

    1. Initial program 65.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg65.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define65.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac265.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub065.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-65.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval65.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified65.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 63.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified63.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Step-by-step derivation
      1. *-un-lft-identity63.2%

        \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(\frac{x + -1}{y} + -1\right)} \]
      2. +-commutative63.2%

        \[\leadsto 1 - 1 \cdot \mathsf{log1p}\left(\color{blue}{-1 + \frac{x + -1}{y}}\right) \]
    9. Applied egg-rr63.2%

      \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
    10. Step-by-step derivation
      1. *-lft-identity63.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
      2. log1p-define63.2%

        \[\leadsto 1 - \color{blue}{\log \left(1 + \left(-1 + \frac{x + -1}{y}\right)\right)} \]
      3. associate-+r+97.8%

        \[\leadsto 1 - \log \color{blue}{\left(\left(1 + -1\right) + \frac{x + -1}{y}\right)} \]
      4. metadata-eval97.8%

        \[\leadsto 1 - \log \left(\color{blue}{0} + \frac{x + -1}{y}\right) \]
      5. +-lft-identity97.8%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{x + -1}{y}\right)} \]
      6. +-commutative97.8%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1 + x}}{y}\right) \]
    11. Simplified97.8%

      \[\leadsto 1 - \color{blue}{\log \left(\frac{-1 + x}{y}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification97.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1.85:\\ \;\;\;\;\log \left(e \cdot \frac{y}{x + -1}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 98.6% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.7:\\ \;\;\;\;\log \left(y \cdot \frac{e}{x + -1}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1.7)
   (log (* y (/ E (+ x -1.0))))
   (if (<= y 1.0) (- (- 1.0 y) (log1p (- x))) (- 1.0 (log (/ (+ x -1.0) y))))))
double code(double x, double y) {
	double tmp;
	if (y <= -1.7) {
		tmp = log((y * (((double) M_E) / (x + -1.0))));
	} else if (y <= 1.0) {
		tmp = (1.0 - y) - log1p(-x);
	} else {
		tmp = 1.0 - log(((x + -1.0) / y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1.7) {
		tmp = Math.log((y * (Math.E / (x + -1.0))));
	} else if (y <= 1.0) {
		tmp = (1.0 - y) - Math.log1p(-x);
	} else {
		tmp = 1.0 - Math.log(((x + -1.0) / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1.7:
		tmp = math.log((y * (math.e / (x + -1.0))))
	elif y <= 1.0:
		tmp = (1.0 - y) - math.log1p(-x)
	else:
		tmp = 1.0 - math.log(((x + -1.0) / y))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1.7)
		tmp = log(Float64(y * Float64(exp(1) / Float64(x + -1.0))));
	elseif (y <= 1.0)
		tmp = Float64(Float64(1.0 - y) - log1p(Float64(-x)));
	else
		tmp = Float64(1.0 - log(Float64(Float64(x + -1.0) / y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1.7], N[Log[N[(y * N[(E / N[(x + -1.0), $MachinePrecision]), $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[N[(N[(x + -1.0), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.7:\\
\;\;\;\;\log \left(y \cdot \frac{e}{x + -1}\right)\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1.69999999999999996

    1. Initial program 25.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 97.8%

      \[\leadsto 1 - \color{blue}{\left(\log \left(-1 \cdot \left(x - 1\right)\right) + \left(\log \left(\frac{-1}{y}\right) + -1 \cdot \frac{\frac{1}{x - 1} - \frac{x}{x - 1}}{y}\right)\right)} \]
    6. Simplified97.8%

      \[\leadsto 1 - \color{blue}{\left(\mathsf{log1p}\left(-x\right) + \left(\frac{1}{y} + \log \left(\frac{-1}{y}\right)\right)\right)} \]
    7. Step-by-step derivation
      1. associate--r+97.8%

        \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \left(\frac{1}{y} + \log \left(\frac{-1}{y}\right)\right)} \]
      2. add-log-exp97.8%

        \[\leadsto \color{blue}{\log \left(e^{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \left(\frac{1}{y} + \log \left(\frac{-1}{y}\right)\right)}\right)} \]
      3. exp-diff97.8%

        \[\leadsto \log \color{blue}{\left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{e^{\frac{1}{y} + \log \left(\frac{-1}{y}\right)}}\right)} \]
      4. +-commutative97.8%

        \[\leadsto \log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{e^{\color{blue}{\log \left(\frac{-1}{y}\right) + \frac{1}{y}}}}\right) \]
      5. exp-sum97.8%

        \[\leadsto \log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{\color{blue}{e^{\log \left(\frac{-1}{y}\right)} \cdot e^{\frac{1}{y}}}}\right) \]
      6. add-exp-log97.8%

        \[\leadsto \log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{\color{blue}{\frac{-1}{y}} \cdot e^{\frac{1}{y}}}\right) \]
    8. Applied egg-rr97.8%

      \[\leadsto \color{blue}{\log \left(\frac{e^{1 - \mathsf{log1p}\left(-x\right)}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right)} \]
    9. Step-by-step derivation
      1. exp-diff97.8%

        \[\leadsto \log \left(\frac{\color{blue}{\frac{e^{1}}{e^{\mathsf{log1p}\left(-x\right)}}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
      2. exp-1-e97.8%

        \[\leadsto \log \left(\frac{\frac{\color{blue}{e}}{e^{\mathsf{log1p}\left(-x\right)}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
      3. log1p-undefine97.8%

        \[\leadsto \log \left(\frac{\frac{e}{e^{\color{blue}{\log \left(1 + \left(-x\right)\right)}}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
      4. neg-mul-197.8%

        \[\leadsto \log \left(\frac{\frac{e}{e^{\log \left(1 + \color{blue}{-1 \cdot x}\right)}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
      5. rem-exp-log98.1%

        \[\leadsto \log \left(\frac{\frac{e}{\color{blue}{1 + -1 \cdot x}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
      6. neg-mul-198.1%

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

        \[\leadsto \log \left(\frac{\frac{e}{\color{blue}{1 - x}}}{\frac{-1}{y} \cdot e^{\frac{1}{y}}}\right) \]
      8. associate-*l/98.1%

        \[\leadsto \log \left(\frac{\frac{e}{1 - x}}{\color{blue}{\frac{-1 \cdot e^{\frac{1}{y}}}{y}}}\right) \]
      9. mul-1-neg98.1%

        \[\leadsto \log \left(\frac{\frac{e}{1 - x}}{\frac{\color{blue}{-e^{\frac{1}{y}}}}{y}}\right) \]
    10. Simplified98.1%

      \[\leadsto \color{blue}{\log \left(\frac{\frac{e}{1 - x}}{\frac{-e^{\frac{1}{y}}}{y}}\right)} \]
    11. Taylor expanded in y around inf 96.4%

      \[\leadsto \log \color{blue}{\left(-1 \cdot \frac{y \cdot e}{1 - x}\right)} \]
    12. Step-by-step derivation
      1. mul-1-neg96.4%

        \[\leadsto \log \color{blue}{\left(-\frac{y \cdot e}{1 - x}\right)} \]
      2. associate-/l*96.5%

        \[\leadsto \log \left(-\color{blue}{y \cdot \frac{e}{1 - x}}\right) \]
      3. distribute-rgt-neg-in96.5%

        \[\leadsto \log \color{blue}{\left(y \cdot \left(-\frac{e}{1 - x}\right)\right)} \]
      4. distribute-neg-frac296.5%

        \[\leadsto \log \left(y \cdot \color{blue}{\frac{e}{-\left(1 - x\right)}}\right) \]
      5. neg-sub096.5%

        \[\leadsto \log \left(y \cdot \frac{e}{\color{blue}{0 - \left(1 - x\right)}}\right) \]
      6. sub-neg96.5%

        \[\leadsto \log \left(y \cdot \frac{e}{0 - \color{blue}{\left(1 + \left(-x\right)\right)}}\right) \]
      7. associate--r+96.5%

        \[\leadsto \log \left(y \cdot \frac{e}{\color{blue}{\left(0 - 1\right) - \left(-x\right)}}\right) \]
      8. metadata-eval96.5%

        \[\leadsto \log \left(y \cdot \frac{e}{\color{blue}{-1} - \left(-x\right)}\right) \]
    13. Simplified96.5%

      \[\leadsto \log \color{blue}{\left(y \cdot \frac{e}{-1 - \left(-x\right)}\right)} \]

    if -1.69999999999999996 < 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 98.4%

      \[\leadsto \color{blue}{\left(1 + y \cdot \left(\frac{x}{1 + -1 \cdot x} - \frac{1}{1 + -1 \cdot x}\right)\right) - \log \left(1 + -1 \cdot x\right)} \]
    6. Simplified98.4%

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

    if 1 < y

    1. Initial program 65.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg65.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define65.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac265.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub065.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-65.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval65.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified65.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 63.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval63.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified63.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Step-by-step derivation
      1. *-un-lft-identity63.2%

        \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(\frac{x + -1}{y} + -1\right)} \]
      2. +-commutative63.2%

        \[\leadsto 1 - 1 \cdot \mathsf{log1p}\left(\color{blue}{-1 + \frac{x + -1}{y}}\right) \]
    9. Applied egg-rr63.2%

      \[\leadsto 1 - \color{blue}{1 \cdot \mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
    10. Step-by-step derivation
      1. *-lft-identity63.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 + \frac{x + -1}{y}\right)} \]
      2. log1p-define63.2%

        \[\leadsto 1 - \color{blue}{\log \left(1 + \left(-1 + \frac{x + -1}{y}\right)\right)} \]
      3. associate-+r+97.8%

        \[\leadsto 1 - \log \color{blue}{\left(\left(1 + -1\right) + \frac{x + -1}{y}\right)} \]
      4. metadata-eval97.8%

        \[\leadsto 1 - \log \left(\color{blue}{0} + \frac{x + -1}{y}\right) \]
      5. +-lft-identity97.8%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{x + -1}{y}\right)} \]
      6. +-commutative97.8%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1 + x}}{y}\right) \]
    11. Simplified97.8%

      \[\leadsto 1 - \color{blue}{\log \left(\frac{-1 + x}{y}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification97.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1.7:\\ \;\;\;\;\log \left(y \cdot \frac{e}{x + -1}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 79.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -4.6:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -4.6) (- 1.0 (log (/ -1.0 y))) (- (- 1.0 y) (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if (y <= -4.6) {
		tmp = 1.0 - log((-1.0 / y));
	} else {
		tmp = (1.0 - y) - log1p(-x);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -4.6) {
		tmp = 1.0 - Math.log((-1.0 / y));
	} else {
		tmp = (1.0 - y) - Math.log1p(-x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -4.6:
		tmp = 1.0 - math.log((-1.0 / y))
	else:
		tmp = (1.0 - y) - math.log1p(-x)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -4.6)
		tmp = Float64(1.0 - log(Float64(-1.0 / y)));
	else
		tmp = Float64(Float64(1.0 - y) - log1p(Float64(-x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -4.6], N[(1.0 - N[Log[N[(-1.0 / 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 -4.6:\\
\;\;\;\;1 - \log \left(\frac{-1}{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 < -4.5999999999999996

    1. Initial program 25.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 22.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified22.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Taylor expanded in x around 0 71.4%

      \[\leadsto 1 - \color{blue}{\log \left(-\frac{1}{y}\right)} \]
    9. Step-by-step derivation
      1. distribute-neg-frac71.4%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval71.4%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    10. Simplified71.4%

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

    if -4.5999999999999996 < y

    1. Initial program 94.2%

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

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

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac294.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub094.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-94.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval94.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative94.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified94.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 82.0%

      \[\leadsto \color{blue}{\left(1 + y \cdot \left(\frac{x}{1 + -1 \cdot x} - \frac{1}{1 + -1 \cdot x}\right)\right) - \log \left(1 + -1 \cdot x\right)} \]
    6. Simplified82.0%

      \[\leadsto \color{blue}{\left(1 - y\right) - \mathsf{log1p}\left(-x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification78.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -4.6:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 - y\right) - \mathsf{log1p}\left(-x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 79.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -4.5:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -4.5) (- 1.0 (log (/ -1.0 y))) (- 1.0 (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if (y <= -4.5) {
		tmp = 1.0 - log((-1.0 / y));
	} else {
		tmp = 1.0 - log1p(-x);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -4.5) {
		tmp = 1.0 - Math.log((-1.0 / y));
	} else {
		tmp = 1.0 - Math.log1p(-x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -4.5:
		tmp = 1.0 - math.log((-1.0 / y))
	else:
		tmp = 1.0 - math.log1p(-x)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -4.5)
		tmp = Float64(1.0 - log(Float64(-1.0 / y)));
	else
		tmp = Float64(1.0 - log1p(Float64(-x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -4.5], N[(1.0 - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -4.5:\\
\;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -4.5

    1. Initial program 25.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative25.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 22.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Step-by-step derivation
      1. +-commutative22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x}{y} - \color{blue}{\left(\frac{1}{y} + 1\right)}\right) \]
      2. associate--r+22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) - 1}\right) \]
      3. sub-neg22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\left(\frac{x}{y} - \frac{1}{y}\right) + \left(-1\right)}\right) \]
      4. div-sub22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - 1}{y}} + \left(-1\right)\right) \]
      5. sub-neg22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x + \left(-1\right)}}{y} + \left(-1\right)\right) \]
      6. metadata-eval22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + \color{blue}{-1}}{y} + \left(-1\right)\right) \]
      7. metadata-eval22.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x + -1}{y} + \color{blue}{-1}\right) \]
    7. Simplified22.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x + -1}{y} + -1}\right) \]
    8. Taylor expanded in x around 0 71.4%

      \[\leadsto 1 - \color{blue}{\log \left(-\frac{1}{y}\right)} \]
    9. Step-by-step derivation
      1. distribute-neg-frac71.4%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval71.4%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    10. Simplified71.4%

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

    if -4.5 < y

    1. Initial program 94.2%

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

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

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac294.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub094.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-94.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval94.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative94.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified94.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 81.0%

      \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
    6. Step-by-step derivation
      1. log1p-define81.1%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
      2. mul-1-neg81.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
    7. Simplified81.1%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -4.5:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 62.5% 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 70.5%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg70.5%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define70.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac270.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub070.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified70.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 57.9%

    \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define57.9%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg57.9%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified57.9%

    \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  8. Final simplification57.9%

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

Alternative 9: 43.8% 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 70.5%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg70.5%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define70.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac270.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub070.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified70.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 57.9%

    \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define57.9%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg57.9%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified57.9%

    \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  8. Taylor expanded in x around 0 40.2%

    \[\leadsto \color{blue}{1 + x} \]
  9. Final simplification40.2%

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

Alternative 10: 43.6% 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 70.5%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg70.5%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define70.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac270.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub070.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative70.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified70.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 57.9%

    \[\leadsto 1 - \color{blue}{\log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define57.9%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg57.9%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified57.9%

    \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-x\right)} \]
  8. Taylor expanded in x around 0 39.7%

    \[\leadsto \color{blue}{1} \]
  9. Final simplification39.7%

    \[\leadsto 1 \]
  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 2024115 
(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))))))