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

Percentage Accurate: 72.8% → 99.7%
Time: 12.7s
Alternatives: 11
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 11 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 72.8% 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: 99.7% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1000000:\\ \;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{elif}\;y \leq 3.2 \cdot 10^{+15}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1000000.0)
   (+ 1.0 (- (- (/ -1.0 y) (log (/ -1.0 y))) (log1p (- x))))
   (if (<= y 3.2e+15)
     (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
     (log (/ (* y E) (+ 1.0 x))))))
double code(double x, double y) {
	double tmp;
	if (y <= -1000000.0) {
		tmp = 1.0 + (((-1.0 / y) - log((-1.0 / y))) - log1p(-x));
	} else if (y <= 3.2e+15) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = log(((y * ((double) M_E)) / (1.0 + x)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1000000.0) {
		tmp = 1.0 + (((-1.0 / y) - Math.log((-1.0 / y))) - Math.log1p(-x));
	} else if (y <= 3.2e+15) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = Math.log(((y * Math.E) / (1.0 + x)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1000000.0:
		tmp = 1.0 + (((-1.0 / y) - math.log((-1.0 / y))) - math.log1p(-x))
	elif y <= 3.2e+15:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = math.log(((y * math.e) / (1.0 + x)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1000000.0)
		tmp = Float64(1.0 + Float64(Float64(Float64(-1.0 / y) - log(Float64(-1.0 / y))) - log1p(Float64(-x))));
	elseif (y <= 3.2e+15)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = log(Float64(Float64(y * exp(1)) / Float64(1.0 + x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1000000.0], N[(1.0 + N[(N[(N[(-1.0 / y), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 3.2e+15], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(y * E), $MachinePrecision] / N[(1.0 + x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1000000:\\
\;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\

\mathbf{elif}\;y \leq 3.2 \cdot 10^{+15}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1e6

    1. Initial program 21.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg21.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define21.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac221.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub021.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified21.2%

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

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

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

    if -1e6 < y < 3.2e15

    1. Initial program 100.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg100.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      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 3.2e15 < y

    1. Initial program 57.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg57.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define57.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac257.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub057.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified57.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+0.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define0.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg0.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified0.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Step-by-step derivation
      1. sub-neg0.0%

        \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. add-log-exp0.0%

        \[\leadsto \color{blue}{\log \left(e^{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)}\right)} \]
      3. exp-sum0.0%

        \[\leadsto \log \color{blue}{\left(e^{1 - \mathsf{log1p}\left(-x\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right)} \]
      4. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{-x} \cdot \sqrt{-x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      5. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{\left(-x\right) \cdot \left(-x\right)}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      6. sqr-neg0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\sqrt{\color{blue}{x \cdot x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{x} \cdot \sqrt{x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      8. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{x}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      9. neg-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)}}\right) \]
      10. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      11. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(y \cdot \frac{1}{-1}\right)}}\right) \]
      12. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{-1}\right)}\right) \]
      13. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{\frac{1}{-1}}\right)}\right) \]
      14. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      15. add-exp-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{y}{-1}}\right) \]
      16. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{1}{\frac{-1}{y}}}\right) \]
      17. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y}} \cdot \sqrt{\frac{-1}{y}}}}\right) \]
      18. sqrt-unprod43.5%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y} \cdot \frac{-1}{y}}}}\right) \]
      19. frac-times42.2%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\sqrt{\color{blue}{\frac{-1 \cdot -1}{y \cdot y}}}}\right) \]
    9. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot y\right)} \]
    10. Step-by-step derivation
      1. *-commutative98.5%

        \[\leadsto \log \color{blue}{\left(y \cdot e^{1 - \mathsf{log1p}\left(x\right)}\right)} \]
      2. exp-diff98.5%

        \[\leadsto \log \left(y \cdot \color{blue}{\frac{e^{1}}{e^{\mathsf{log1p}\left(x\right)}}}\right) \]
      3. associate-*r/98.6%

        \[\leadsto \log \color{blue}{\left(\frac{y \cdot e^{1}}{e^{\mathsf{log1p}\left(x\right)}}\right)} \]
      4. exp-1-e98.6%

        \[\leadsto \log \left(\frac{y \cdot \color{blue}{e}}{e^{\mathsf{log1p}\left(x\right)}}\right) \]
      5. log1p-undefine98.6%

        \[\leadsto \log \left(\frac{y \cdot e}{e^{\color{blue}{\log \left(1 + x\right)}}}\right) \]
      6. rem-exp-log100.0%

        \[\leadsto \log \left(\frac{y \cdot e}{\color{blue}{1 + x}}\right) \]
    11. Applied egg-rr100.0%

      \[\leadsto \log \color{blue}{\left(\frac{y \cdot e}{1 + x}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1000000:\\ \;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{elif}\;y \leq 3.2 \cdot 10^{+15}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 98.1% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7.6 \cdot 10^{+33}:\\ \;\;\;\;\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 1.5 \cdot 10^{+16}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\left(x - y\right) \cdot \frac{1}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7.6e+33)
   (- (- 1.0 (log1p (- x))) (log (/ -1.0 y)))
   (if (<= y 1.5e+16)
     (- 1.0 (log1p (* (- x y) (/ 1.0 (+ y -1.0)))))
     (log (/ (* y E) (+ 1.0 x))))))
double code(double x, double y) {
	double tmp;
	if (y <= -7.6e+33) {
		tmp = (1.0 - log1p(-x)) - log((-1.0 / y));
	} else if (y <= 1.5e+16) {
		tmp = 1.0 - log1p(((x - y) * (1.0 / (y + -1.0))));
	} else {
		tmp = log(((y * ((double) M_E)) / (1.0 + x)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -7.6e+33) {
		tmp = (1.0 - Math.log1p(-x)) - Math.log((-1.0 / y));
	} else if (y <= 1.5e+16) {
		tmp = 1.0 - Math.log1p(((x - y) * (1.0 / (y + -1.0))));
	} else {
		tmp = Math.log(((y * Math.E) / (1.0 + x)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -7.6e+33:
		tmp = (1.0 - math.log1p(-x)) - math.log((-1.0 / y))
	elif y <= 1.5e+16:
		tmp = 1.0 - math.log1p(((x - y) * (1.0 / (y + -1.0))))
	else:
		tmp = math.log(((y * math.e) / (1.0 + x)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -7.6e+33)
		tmp = Float64(Float64(1.0 - log1p(Float64(-x))) - log(Float64(-1.0 / y)));
	elseif (y <= 1.5e+16)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) * Float64(1.0 / Float64(y + -1.0)))));
	else
		tmp = log(Float64(Float64(y * exp(1)) / Float64(1.0 + x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -7.6e+33], N[(N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.5e+16], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] * N[(1.0 / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(y * E), $MachinePrecision] / N[(1.0 + x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -7.6 \cdot 10^{+33}:\\
\;\;\;\;\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\\

\mathbf{elif}\;y \leq 1.5 \cdot 10^{+16}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\left(x - y\right) \cdot \frac{1}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -7.60000000000000005e33

    1. Initial program 15.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg15.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define15.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac215.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub015.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified15.7%

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

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+99.5%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg99.5%

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

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

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

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

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

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

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

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

    if -7.60000000000000005e33 < y < 1.5e16

    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-define99.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      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
    5. Step-by-step derivation
      1. clear-num99.8%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    6. Applied egg-rr99.8%

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

    if 1.5e16 < y

    1. Initial program 57.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg57.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define57.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac257.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub057.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified57.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+0.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define0.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg0.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified0.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Step-by-step derivation
      1. sub-neg0.0%

        \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. add-log-exp0.0%

        \[\leadsto \color{blue}{\log \left(e^{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)}\right)} \]
      3. exp-sum0.0%

        \[\leadsto \log \color{blue}{\left(e^{1 - \mathsf{log1p}\left(-x\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right)} \]
      4. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{-x} \cdot \sqrt{-x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      5. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{\left(-x\right) \cdot \left(-x\right)}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      6. sqr-neg0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\sqrt{\color{blue}{x \cdot x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{x} \cdot \sqrt{x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      8. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{x}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      9. neg-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)}}\right) \]
      10. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      11. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(y \cdot \frac{1}{-1}\right)}}\right) \]
      12. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{-1}\right)}\right) \]
      13. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{\frac{1}{-1}}\right)}\right) \]
      14. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      15. add-exp-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{y}{-1}}\right) \]
      16. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{1}{\frac{-1}{y}}}\right) \]
      17. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y}} \cdot \sqrt{\frac{-1}{y}}}}\right) \]
      18. sqrt-unprod43.5%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y} \cdot \frac{-1}{y}}}}\right) \]
      19. frac-times42.2%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\sqrt{\color{blue}{\frac{-1 \cdot -1}{y \cdot y}}}}\right) \]
    9. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot y\right)} \]
    10. Step-by-step derivation
      1. *-commutative98.5%

        \[\leadsto \log \color{blue}{\left(y \cdot e^{1 - \mathsf{log1p}\left(x\right)}\right)} \]
      2. exp-diff98.5%

        \[\leadsto \log \left(y \cdot \color{blue}{\frac{e^{1}}{e^{\mathsf{log1p}\left(x\right)}}}\right) \]
      3. associate-*r/98.6%

        \[\leadsto \log \color{blue}{\left(\frac{y \cdot e^{1}}{e^{\mathsf{log1p}\left(x\right)}}\right)} \]
      4. exp-1-e98.6%

        \[\leadsto \log \left(\frac{y \cdot \color{blue}{e}}{e^{\mathsf{log1p}\left(x\right)}}\right) \]
      5. log1p-undefine98.6%

        \[\leadsto \log \left(\frac{y \cdot e}{e^{\color{blue}{\log \left(1 + x\right)}}}\right) \]
      6. rem-exp-log100.0%

        \[\leadsto \log \left(\frac{y \cdot e}{\color{blue}{1 + x}}\right) \]
    11. Applied egg-rr100.0%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -7.6 \cdot 10^{+33}:\\ \;\;\;\;\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 1.5 \cdot 10^{+16}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\left(x - y\right) \cdot \frac{1}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 72.9% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{x - y}{1 - y} \leq 1:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (/ (- x y) (- 1.0 y)) 1.0)
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
   (- 1.0 (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 - 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 - 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 - 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(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[(1.0 - 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}:\\
\;\;\;\;1 - \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 74.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg74.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define74.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac274.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub074.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-74.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval74.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative74.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified74.5%

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

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

    1. Initial program 74.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg74.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define74.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac274.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub074.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-74.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval74.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative74.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified74.5%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 13.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Taylor expanded in x around 0 22.4%

      \[\leadsto \color{blue}{1 - \log \left(-\frac{1}{y}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac22.4%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval22.4%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    8. Simplified22.4%

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

Alternative 4: 88.2% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.2 \cdot 10^{+34}:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 10200000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1.2e+34)
   (- 1.0 (log (/ -1.0 y)))
   (if (<= y 10200000000000.0)
     (- 1.0 (log1p (/ x (+ y -1.0))))
     (log (/ (* y E) (+ 1.0 x))))))
double code(double x, double y) {
	double tmp;
	if (y <= -1.2e+34) {
		tmp = 1.0 - log((-1.0 / y));
	} else if (y <= 10200000000000.0) {
		tmp = 1.0 - log1p((x / (y + -1.0)));
	} else {
		tmp = log(((y * ((double) M_E)) / (1.0 + x)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1.2e+34) {
		tmp = 1.0 - Math.log((-1.0 / y));
	} else if (y <= 10200000000000.0) {
		tmp = 1.0 - Math.log1p((x / (y + -1.0)));
	} else {
		tmp = Math.log(((y * Math.E) / (1.0 + x)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1.2e+34:
		tmp = 1.0 - math.log((-1.0 / y))
	elif y <= 10200000000000.0:
		tmp = 1.0 - math.log1p((x / (y + -1.0)))
	else:
		tmp = math.log(((y * math.e) / (1.0 + x)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1.2e+34)
		tmp = Float64(1.0 - log(Float64(-1.0 / y)));
	elseif (y <= 10200000000000.0)
		tmp = Float64(1.0 - log1p(Float64(x / Float64(y + -1.0))));
	else
		tmp = log(Float64(Float64(y * exp(1)) / Float64(1.0 + x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1.2e+34], N[(1.0 - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 10200000000000.0], N[(1.0 - N[Log[1 + N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(y * E), $MachinePrecision] / N[(1.0 + x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.2 \cdot 10^{+34}:\\
\;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\

\mathbf{elif}\;y \leq 10200000000000:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1.19999999999999993e34

    1. Initial program 15.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg15.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define15.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac215.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub015.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified15.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 15.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Taylor expanded in x around 0 75.3%

      \[\leadsto \color{blue}{1 - \log \left(-\frac{1}{y}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac75.3%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval75.3%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    8. Simplified75.3%

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

    if -1.19999999999999993e34 < y < 1.02e13

    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-define99.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      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
    5. Taylor expanded in x around inf 98.2%

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

    if 1.02e13 < y

    1. Initial program 57.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg57.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define57.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac257.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub057.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative57.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified57.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+0.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define0.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg0.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified0.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Step-by-step derivation
      1. sub-neg0.0%

        \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. add-log-exp0.0%

        \[\leadsto \color{blue}{\log \left(e^{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)}\right)} \]
      3. exp-sum0.0%

        \[\leadsto \log \color{blue}{\left(e^{1 - \mathsf{log1p}\left(-x\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right)} \]
      4. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{-x} \cdot \sqrt{-x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      5. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{\left(-x\right) \cdot \left(-x\right)}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      6. sqr-neg0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\sqrt{\color{blue}{x \cdot x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{x} \cdot \sqrt{x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      8. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{x}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      9. neg-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)}}\right) \]
      10. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      11. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(y \cdot \frac{1}{-1}\right)}}\right) \]
      12. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{-1}\right)}\right) \]
      13. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{\frac{1}{-1}}\right)}\right) \]
      14. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      15. add-exp-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{y}{-1}}\right) \]
      16. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{1}{\frac{-1}{y}}}\right) \]
      17. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y}} \cdot \sqrt{\frac{-1}{y}}}}\right) \]
      18. sqrt-unprod43.5%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y} \cdot \frac{-1}{y}}}}\right) \]
      19. frac-times42.2%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\sqrt{\color{blue}{\frac{-1 \cdot -1}{y \cdot y}}}}\right) \]
    9. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot y\right)} \]
    10. Step-by-step derivation
      1. *-commutative98.5%

        \[\leadsto \log \color{blue}{\left(y \cdot e^{1 - \mathsf{log1p}\left(x\right)}\right)} \]
      2. exp-diff98.5%

        \[\leadsto \log \left(y \cdot \color{blue}{\frac{e^{1}}{e^{\mathsf{log1p}\left(x\right)}}}\right) \]
      3. associate-*r/98.6%

        \[\leadsto \log \color{blue}{\left(\frac{y \cdot e^{1}}{e^{\mathsf{log1p}\left(x\right)}}\right)} \]
      4. exp-1-e98.6%

        \[\leadsto \log \left(\frac{y \cdot \color{blue}{e}}{e^{\mathsf{log1p}\left(x\right)}}\right) \]
      5. log1p-undefine98.6%

        \[\leadsto \log \left(\frac{y \cdot e}{e^{\color{blue}{\log \left(1 + x\right)}}}\right) \]
      6. rem-exp-log100.0%

        \[\leadsto \log \left(\frac{y \cdot e}{\color{blue}{1 + x}}\right) \]
    11. Applied egg-rr100.0%

      \[\leadsto \log \color{blue}{\left(\frac{y \cdot e}{1 + x}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification92.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1.2 \cdot 10^{+34}:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 10200000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 89.2% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -10.5:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \left(y + \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{y \cdot e}{1 + x}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -10.5)
   (- 1.0 (log (/ -1.0 y)))
   (if (<= y 1.0) (- 1.0 (+ y (log1p (- x)))) (log (/ (* y E) (+ 1.0 x))))))
double code(double x, double y) {
	double tmp;
	if (y <= -10.5) {
		tmp = 1.0 - log((-1.0 / y));
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + log1p(-x));
	} else {
		tmp = log(((y * ((double) M_E)) / (1.0 + x)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -10.5) {
		tmp = 1.0 - Math.log((-1.0 / y));
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + Math.log1p(-x));
	} else {
		tmp = Math.log(((y * Math.E) / (1.0 + x)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -10.5:
		tmp = 1.0 - math.log((-1.0 / y))
	elif y <= 1.0:
		tmp = 1.0 - (y + math.log1p(-x))
	else:
		tmp = math.log(((y * math.e) / (1.0 + x)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -10.5)
		tmp = Float64(1.0 - log(Float64(-1.0 / y)));
	elseif (y <= 1.0)
		tmp = Float64(1.0 - Float64(y + log1p(Float64(-x))));
	else
		tmp = log(Float64(Float64(y * exp(1)) / Float64(1.0 + x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -10.5], N[(1.0 - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.0], N[(1.0 - N[(y + N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(y * E), $MachinePrecision] / N[(1.0 + x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -10.5:\\
\;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -10.5

    1. Initial program 21.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg21.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define21.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac221.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub021.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified21.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 21.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Taylor expanded in x around 0 71.0%

      \[\leadsto \color{blue}{1 - \log \left(-\frac{1}{y}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac71.0%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval71.0%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    8. Simplified71.0%

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

    if -10.5 < y < 1

    1. Initial program 100.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg100.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      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 99.1%

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

        \[\leadsto 1 - \color{blue}{\left(y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right) + \log \left(1 + -1 \cdot x\right)\right)} \]
      2. div-sub99.1%

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

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

        \[\leadsto 1 - \left(y \cdot \frac{1 - x}{\color{blue}{1 - x}} + \log \left(1 + -1 \cdot x\right)\right) \]
      5. *-inverses99.1%

        \[\leadsto 1 - \left(y \cdot \color{blue}{1} + \log \left(1 + -1 \cdot x\right)\right) \]
      6. *-rgt-identity99.1%

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

        \[\leadsto 1 - \left(y + \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) \]
      8. mul-1-neg99.2%

        \[\leadsto 1 - \left(y + \mathsf{log1p}\left(\color{blue}{-x}\right)\right) \]
    7. Simplified99.2%

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

    if 1 < y

    1. Initial program 58.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg58.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define58.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac258.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub058.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-58.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval58.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative58.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified58.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+0.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval0.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative0.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define0.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg0.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified0.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Step-by-step derivation
      1. sub-neg0.0%

        \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. add-log-exp0.0%

        \[\leadsto \color{blue}{\log \left(e^{\left(1 - \mathsf{log1p}\left(-x\right)\right) + \left(-\log \left(\frac{-1}{y}\right)\right)}\right)} \]
      3. exp-sum0.0%

        \[\leadsto \log \color{blue}{\left(e^{1 - \mathsf{log1p}\left(-x\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right)} \]
      4. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{-x} \cdot \sqrt{-x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      5. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{\left(-x\right) \cdot \left(-x\right)}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      6. sqr-neg0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\sqrt{\color{blue}{x \cdot x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{\sqrt{x} \cdot \sqrt{x}}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      8. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(\color{blue}{x}\right)} \cdot e^{-\log \left(\frac{-1}{y}\right)}\right) \]
      9. neg-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)}}\right) \]
      10. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      11. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(y \cdot \frac{1}{-1}\right)}}\right) \]
      12. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{-1}\right)}\right) \]
      13. metadata-eval0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \left(y \cdot \color{blue}{\frac{1}{-1}}\right)}\right) \]
      14. div-inv0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot e^{\log \color{blue}{\left(\frac{y}{-1}\right)}}\right) \]
      15. add-exp-log0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{y}{-1}}\right) \]
      16. clear-num0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \color{blue}{\frac{1}{\frac{-1}{y}}}\right) \]
      17. add-sqr-sqrt0.0%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y}} \cdot \sqrt{\frac{-1}{y}}}}\right) \]
      18. sqrt-unprod45.9%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\color{blue}{\sqrt{\frac{-1}{y} \cdot \frac{-1}{y}}}}\right) \]
      19. frac-times44.6%

        \[\leadsto \log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot \frac{1}{\sqrt{\color{blue}{\frac{-1 \cdot -1}{y \cdot y}}}}\right) \]
    9. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\log \left(e^{1 - \mathsf{log1p}\left(x\right)} \cdot y\right)} \]
    10. Step-by-step derivation
      1. *-commutative98.5%

        \[\leadsto \log \color{blue}{\left(y \cdot e^{1 - \mathsf{log1p}\left(x\right)}\right)} \]
      2. exp-diff98.5%

        \[\leadsto \log \left(y \cdot \color{blue}{\frac{e^{1}}{e^{\mathsf{log1p}\left(x\right)}}}\right) \]
      3. associate-*r/98.5%

        \[\leadsto \log \color{blue}{\left(\frac{y \cdot e^{1}}{e^{\mathsf{log1p}\left(x\right)}}\right)} \]
      4. exp-1-e98.5%

        \[\leadsto \log \left(\frac{y \cdot \color{blue}{e}}{e^{\mathsf{log1p}\left(x\right)}}\right) \]
      5. log1p-undefine98.5%

        \[\leadsto \log \left(\frac{y \cdot e}{e^{\color{blue}{\log \left(1 + x\right)}}}\right) \]
      6. rem-exp-log99.9%

        \[\leadsto \log \left(\frac{y \cdot e}{\color{blue}{1 + x}}\right) \]
    11. Applied egg-rr99.9%

      \[\leadsto \log \color{blue}{\left(\frac{y \cdot e}{1 + x}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 6: 85.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -13.5:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \left(y + \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -13.5)
   (- 1.0 (log (/ -1.0 y)))
   (if (<= y 1.0) (- 1.0 (+ y (log1p (- x)))) (- 1.0 (log1p (/ x y))))))
double code(double x, double y) {
	double tmp;
	if (y <= -13.5) {
		tmp = 1.0 - log((-1.0 / y));
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + log1p(-x));
	} else {
		tmp = 1.0 - log1p((x / y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -13.5) {
		tmp = 1.0 - Math.log((-1.0 / y));
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + Math.log1p(-x));
	} else {
		tmp = 1.0 - Math.log1p((x / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -13.5:
		tmp = 1.0 - math.log((-1.0 / y))
	elif y <= 1.0:
		tmp = 1.0 - (y + math.log1p(-x))
	else:
		tmp = 1.0 - math.log1p((x / y))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -13.5)
		tmp = Float64(1.0 - log(Float64(-1.0 / y)));
	elseif (y <= 1.0)
		tmp = Float64(1.0 - Float64(y + log1p(Float64(-x))));
	else
		tmp = Float64(1.0 - log1p(Float64(x / y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -13.5], N[(1.0 - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.0], N[(1.0 - N[(y + N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -13.5:\\
\;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -13.5

    1. Initial program 21.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg21.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define21.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac221.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub021.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative21.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified21.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 21.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Taylor expanded in x around 0 71.0%

      \[\leadsto \color{blue}{1 - \log \left(-\frac{1}{y}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac71.0%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval71.0%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    8. Simplified71.0%

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

    if -13.5 < y < 1

    1. Initial program 100.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg100.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      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 99.1%

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

        \[\leadsto 1 - \color{blue}{\left(y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right) + \log \left(1 + -1 \cdot x\right)\right)} \]
      2. div-sub99.1%

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

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

        \[\leadsto 1 - \left(y \cdot \frac{1 - x}{\color{blue}{1 - x}} + \log \left(1 + -1 \cdot x\right)\right) \]
      5. *-inverses99.1%

        \[\leadsto 1 - \left(y \cdot \color{blue}{1} + \log \left(1 + -1 \cdot x\right)\right) \]
      6. *-rgt-identity99.1%

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

        \[\leadsto 1 - \left(y + \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) \]
      8. mul-1-neg99.2%

        \[\leadsto 1 - \left(y + \mathsf{log1p}\left(\color{blue}{-x}\right)\right) \]
    7. Simplified99.2%

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

    if 1 < y

    1. Initial program 58.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg58.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define58.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac258.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub058.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-58.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval58.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative58.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified58.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 48.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 48.0%

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

Alternative 7: 82.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7.6 \cdot 10^{+33}:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 6.2 \cdot 10^{-12}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7.6e+33)
   (- 1.0 (log (/ -1.0 y)))
   (if (<= y 6.2e-12) (- 1.0 (log1p (- x))) (- 1.0 (log1p (/ x y))))))
double code(double x, double y) {
	double tmp;
	if (y <= -7.6e+33) {
		tmp = 1.0 - log((-1.0 / y));
	} else if (y <= 6.2e-12) {
		tmp = 1.0 - log1p(-x);
	} else {
		tmp = 1.0 - log1p((x / y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -7.6e+33) {
		tmp = 1.0 - Math.log((-1.0 / y));
	} else if (y <= 6.2e-12) {
		tmp = 1.0 - Math.log1p(-x);
	} else {
		tmp = 1.0 - Math.log1p((x / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -7.6e+33:
		tmp = 1.0 - math.log((-1.0 / y))
	elif y <= 6.2e-12:
		tmp = 1.0 - math.log1p(-x)
	else:
		tmp = 1.0 - math.log1p((x / y))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -7.6e+33)
		tmp = Float64(1.0 - log(Float64(-1.0 / y)));
	elseif (y <= 6.2e-12)
		tmp = Float64(1.0 - log1p(Float64(-x)));
	else
		tmp = Float64(1.0 - log1p(Float64(x / y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -7.6e+33], N[(1.0 - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 6.2e-12], N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -7.6 \cdot 10^{+33}:\\
\;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\

\mathbf{elif}\;y \leq 6.2 \cdot 10^{-12}:\\
\;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -7.60000000000000005e33

    1. Initial program 15.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg15.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define15.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac215.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub015.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified15.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 15.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Taylor expanded in x around 0 75.3%

      \[\leadsto \color{blue}{1 - \log \left(-\frac{1}{y}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac75.3%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval75.3%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    8. Simplified75.3%

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

    if -7.60000000000000005e33 < y < 6.2000000000000002e-12

    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-define99.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      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
    5. Taylor expanded in y around 0 96.0%

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

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

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

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

    if 6.2000000000000002e-12 < y

    1. Initial program 60.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg60.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define60.6%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac260.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub060.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-60.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval60.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative60.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified60.6%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 49.3%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 49.2%

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

Alternative 8: 78.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7.6 \cdot 10^{+33}:\\ \;\;\;\;1 - \log \left(\frac{-1}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7.6e+33) (- 1.0 (log (/ -1.0 y))) (- 1.0 (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if (y <= -7.6e+33) {
		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 <= -7.6e+33) {
		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 <= -7.6e+33:
		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 <= -7.6e+33)
		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, -7.6e+33], 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 -7.6 \cdot 10^{+33}:\\
\;\;\;\;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 < -7.60000000000000005e33

    1. Initial program 15.7%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg15.7%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define15.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac215.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub015.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative15.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified15.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 15.7%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y} - \left(1 + \frac{1}{y}\right)}\right) \]
    6. Taylor expanded in x around 0 75.3%

      \[\leadsto \color{blue}{1 - \log \left(-\frac{1}{y}\right)} \]
    7. Step-by-step derivation
      1. distribute-neg-frac75.3%

        \[\leadsto 1 - \log \color{blue}{\left(\frac{-1}{y}\right)} \]
      2. metadata-eval75.3%

        \[\leadsto 1 - \log \left(\frac{\color{blue}{-1}}{y}\right) \]
    8. Simplified75.3%

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

    if -7.60000000000000005e33 < y

    1. Initial program 94.8%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg94.8%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define94.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac294.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub094.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-94.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval94.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative94.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified94.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 84.3%

      \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
    6. Step-by-step derivation
      1. log1p-define84.3%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
      2. mul-1-neg84.3%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
    7. Simplified84.3%

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

Alternative 9: 63.6% 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 74.4%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg74.4%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define74.5%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac274.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub074.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified74.5%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 65.8%

    \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define65.8%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg65.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified65.8%

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

Alternative 10: 45.3% 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 74.4%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg74.4%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define74.5%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac274.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub074.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified74.5%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 74.4%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 44.2%

    \[\leadsto \color{blue}{1 + -1 \cdot \frac{x}{y - 1}} \]
  7. Step-by-step derivation
    1. mul-1-neg44.2%

      \[\leadsto 1 + \color{blue}{\left(-\frac{x}{y - 1}\right)} \]
    2. sub-neg44.2%

      \[\leadsto 1 + \left(-\frac{x}{\color{blue}{y + \left(-1\right)}}\right) \]
    3. metadata-eval44.2%

      \[\leadsto 1 + \left(-\frac{x}{y + \color{blue}{-1}}\right) \]
    4. unsub-neg44.2%

      \[\leadsto \color{blue}{1 - \frac{x}{y + -1}} \]
    5. +-commutative44.2%

      \[\leadsto 1 - \frac{x}{\color{blue}{-1 + y}} \]
  8. Simplified44.2%

    \[\leadsto \color{blue}{1 - \frac{x}{-1 + y}} \]
  9. Final simplification44.2%

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

Alternative 11: 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 74.4%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg74.4%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define74.5%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac274.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub074.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative74.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified74.5%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 74.4%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 42.2%

    \[\leadsto \color{blue}{1} \]
  7. Add Preprocessing

Developer Target 1: 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 2024163 
(FPCore (x y)
  :name "Numeric.SpecFunctions:invIncompleteGamma from math-functions-0.1.5.2, B"
  :precision binary64

  :alt
  (! :herbie-platform default (if (< y -8128475261947241/100000000) (- 1 (log (- (/ x (* y y)) (- (/ 1 y) (/ x y))))) (if (< y 30094271212461764000000000) (log (/ (exp 1) (- 1 (/ (- x y) (- 1 y))))) (- 1 (log (- (/ x (* y y)) (- (/ 1 y) (/ x y))))))))

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