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

Percentage Accurate: 72.5% → 99.7%
Time: 11.3s
Alternatives: 13
Speedup: 1.0×

Specification

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

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

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 13 alternatives:

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

Initial Program: 72.5% 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?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7500000:\\ \;\;\;\;\frac{\frac{x}{1 - x} + \frac{-1}{1 - x}}{y} + \left(\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\right)\\ \mathbf{elif}\;y \leq 24000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 + \left(\log y - \log \left(x + -1\right)\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7500000.0)
   (+
    (/ (+ (/ x (- 1.0 x)) (/ -1.0 (- 1.0 x))) y)
    (- (- 1.0 (log1p (- x))) (log (/ -1.0 y))))
   (if (<= y 24000000000000.0)
     (- 1.0 (log1p (/ (* x (- 1.0 (/ y x))) (+ y -1.0))))
     (+ 1.0 (- (log y) (log (+ x -1.0)))))))
double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = (((x / (1.0 - x)) + (-1.0 / (1.0 - x))) / y) + ((1.0 - log1p(-x)) - log((-1.0 / y)));
	} else if (y <= 24000000000000.0) {
		tmp = 1.0 - log1p(((x * (1.0 - (y / x))) / (y + -1.0)));
	} else {
		tmp = 1.0 + (log(y) - log((x + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = (((x / (1.0 - x)) + (-1.0 / (1.0 - x))) / y) + ((1.0 - Math.log1p(-x)) - Math.log((-1.0 / y)));
	} else if (y <= 24000000000000.0) {
		tmp = 1.0 - Math.log1p(((x * (1.0 - (y / x))) / (y + -1.0)));
	} else {
		tmp = 1.0 + (Math.log(y) - Math.log((x + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -7500000.0:
		tmp = (((x / (1.0 - x)) + (-1.0 / (1.0 - x))) / y) + ((1.0 - math.log1p(-x)) - math.log((-1.0 / y)))
	elif y <= 24000000000000.0:
		tmp = 1.0 - math.log1p(((x * (1.0 - (y / x))) / (y + -1.0)))
	else:
		tmp = 1.0 + (math.log(y) - math.log((x + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -7500000.0)
		tmp = Float64(Float64(Float64(Float64(x / Float64(1.0 - x)) + Float64(-1.0 / Float64(1.0 - x))) / y) + Float64(Float64(1.0 - log1p(Float64(-x))) - log(Float64(-1.0 / y))));
	elseif (y <= 24000000000000.0)
		tmp = Float64(1.0 - log1p(Float64(Float64(x * Float64(1.0 - Float64(y / x))) / Float64(y + -1.0))));
	else
		tmp = Float64(1.0 + Float64(log(y) - log(Float64(x + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -7500000.0], N[(N[(N[(N[(x / N[(1.0 - x), $MachinePrecision]), $MachinePrecision] + N[(-1.0 / N[(1.0 - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision] + N[(N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 24000000000000.0], N[(1.0 - N[Log[1 + N[(N[(x * N[(1.0 - N[(y / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 + N[(N[Log[y], $MachinePrecision] - N[Log[N[(x + -1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -7500000:\\
\;\;\;\;\frac{\frac{x}{1 - x} + \frac{-1}{1 - x}}{y} + \left(\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\right)\\

\mathbf{elif}\;y \leq 24000000000000:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -7.5e6

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

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

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

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

    if -7.5e6 < y < 2.4e13

    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 x around inf 100.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x \cdot \left(1 + -1 \cdot \frac{y}{x}\right)}}{y + -1}\right) \]
    6. Step-by-step derivation
      1. mul-1-neg100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 + \color{blue}{\left(-\frac{y}{x}\right)}\right)}{y + -1}\right) \]
      2. unsub-neg100.0%

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

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

    if 2.4e13 < y

    1. Initial program 40.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg40.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define40.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac240.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub040.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified40.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 98.6%

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. log-rec98.6%

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

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

        \[\leadsto 1 - \left(\log \color{blue}{\left(x + \left(-1\right)\right)} - \log y\right) \]
      4. metadata-eval98.6%

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
      5. +-commutative98.6%

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -7500000:\\ \;\;\;\;\frac{\frac{x}{1 - x} + \frac{-1}{1 - x}}{y} + \left(\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\right)\\ \mathbf{elif}\;y \leq 24000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 + \left(\log y - \log \left(x + -1\right)\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.7% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7500000:\\ \;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{elif}\;y \leq 32000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 + \left(\log y - \log \left(x + -1\right)\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7500000.0)
   (+ 1.0 (- (- (/ -1.0 y) (log (/ -1.0 y))) (log1p (- x))))
   (if (<= y 32000000000000.0)
     (- 1.0 (log1p (/ (* x (- 1.0 (/ y x))) (+ y -1.0))))
     (+ 1.0 (- (log y) (log (+ x -1.0)))))))
double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = 1.0 + (((-1.0 / y) - log((-1.0 / y))) - log1p(-x));
	} else if (y <= 32000000000000.0) {
		tmp = 1.0 - log1p(((x * (1.0 - (y / x))) / (y + -1.0)));
	} else {
		tmp = 1.0 + (log(y) - log((x + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = 1.0 + (((-1.0 / y) - Math.log((-1.0 / y))) - Math.log1p(-x));
	} else if (y <= 32000000000000.0) {
		tmp = 1.0 - Math.log1p(((x * (1.0 - (y / x))) / (y + -1.0)));
	} else {
		tmp = 1.0 + (Math.log(y) - Math.log((x + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -7500000.0:
		tmp = 1.0 + (((-1.0 / y) - math.log((-1.0 / y))) - math.log1p(-x))
	elif y <= 32000000000000.0:
		tmp = 1.0 - math.log1p(((x * (1.0 - (y / x))) / (y + -1.0)))
	else:
		tmp = 1.0 + (math.log(y) - math.log((x + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -7500000.0)
		tmp = Float64(1.0 + Float64(Float64(Float64(-1.0 / y) - log(Float64(-1.0 / y))) - log1p(Float64(-x))));
	elseif (y <= 32000000000000.0)
		tmp = Float64(1.0 - log1p(Float64(Float64(x * Float64(1.0 - Float64(y / x))) / Float64(y + -1.0))));
	else
		tmp = Float64(1.0 + Float64(log(y) - log(Float64(x + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -7500000.0], 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, 32000000000000.0], N[(1.0 - N[Log[1 + N[(N[(x * N[(1.0 - N[(y / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 + N[(N[Log[y], $MachinePrecision] - N[Log[N[(x + -1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -7500000:\\
\;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\

\mathbf{elif}\;y \leq 32000000000000:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -7.5e6

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

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

      \[\leadsto 1 - \color{blue}{\left(\log \left(-1 \cdot \left(x - 1\right)\right) + \left(\log \left(\frac{-1}{y}\right) + -1 \cdot \frac{\frac{1}{x - 1} - \frac{x}{x - 1}}{y}\right)\right)} \]
    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 -7.5e6 < y < 3.2e13

    1. Initial program 99.9%

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

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

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

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

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

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

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

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

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 100.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x \cdot \left(1 + -1 \cdot \frac{y}{x}\right)}}{y + -1}\right) \]
    6. Step-by-step derivation
      1. mul-1-neg100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 + \color{blue}{\left(-\frac{y}{x}\right)}\right)}{y + -1}\right) \]
      2. unsub-neg100.0%

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

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

    if 3.2e13 < y

    1. Initial program 40.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg40.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define40.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac240.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub040.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified40.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 98.6%

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. log-rec98.6%

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

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

        \[\leadsto 1 - \left(\log \color{blue}{\left(x + \left(-1\right)\right)} - \log y\right) \]
      4. metadata-eval98.6%

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
      5. +-commutative98.6%

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -7500000:\\ \;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{elif}\;y \leq 32000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 + \left(\log y - \log \left(x + -1\right)\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.6% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -2050000000:\\ \;\;\;\;\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 38000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 + \left(\log y - \log \left(x + -1\right)\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -2050000000.0)
   (- (- 1.0 (log1p (- x))) (log (/ -1.0 y)))
   (if (<= y 38000000000000.0)
     (- 1.0 (log1p (/ (* x (- 1.0 (/ y x))) (+ y -1.0))))
     (+ 1.0 (- (log y) (log (+ x -1.0)))))))
double code(double x, double y) {
	double tmp;
	if (y <= -2050000000.0) {
		tmp = (1.0 - log1p(-x)) - log((-1.0 / y));
	} else if (y <= 38000000000000.0) {
		tmp = 1.0 - log1p(((x * (1.0 - (y / x))) / (y + -1.0)));
	} else {
		tmp = 1.0 + (log(y) - log((x + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -2050000000.0) {
		tmp = (1.0 - Math.log1p(-x)) - Math.log((-1.0 / y));
	} else if (y <= 38000000000000.0) {
		tmp = 1.0 - Math.log1p(((x * (1.0 - (y / x))) / (y + -1.0)));
	} else {
		tmp = 1.0 + (Math.log(y) - Math.log((x + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -2050000000.0:
		tmp = (1.0 - math.log1p(-x)) - math.log((-1.0 / y))
	elif y <= 38000000000000.0:
		tmp = 1.0 - math.log1p(((x * (1.0 - (y / x))) / (y + -1.0)))
	else:
		tmp = 1.0 + (math.log(y) - math.log((x + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -2050000000.0)
		tmp = Float64(Float64(1.0 - log1p(Float64(-x))) - log(Float64(-1.0 / y)));
	elseif (y <= 38000000000000.0)
		tmp = Float64(1.0 - log1p(Float64(Float64(x * Float64(1.0 - Float64(y / x))) / Float64(y + -1.0))));
	else
		tmp = Float64(1.0 + Float64(log(y) - log(Float64(x + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -2050000000.0], N[(N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision] - N[Log[N[(-1.0 / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 38000000000000.0], N[(1.0 - N[Log[1 + N[(N[(x * N[(1.0 - N[(y / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 + N[(N[Log[y], $MachinePrecision] - N[Log[N[(x + -1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -2050000000:\\
\;\;\;\;\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\\

\mathbf{elif}\;y \leq 38000000000000:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -2.05e9

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.4%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+99.4%

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

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

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

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

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative99.4%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define99.4%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg99.4%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified99.4%

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

    if -2.05e9 < y < 3.8e13

    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 x around inf 100.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{\color{blue}{x \cdot \left(1 + -1 \cdot \frac{y}{x}\right)}}{y + -1}\right) \]
    6. Step-by-step derivation
      1. mul-1-neg100.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 + \color{blue}{\left(-\frac{y}{x}\right)}\right)}{y + -1}\right) \]
      2. unsub-neg100.0%

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

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

    if 3.8e13 < y

    1. Initial program 40.0%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg40.0%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define40.0%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac240.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub040.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative40.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified40.0%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 98.6%

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. log-rec98.6%

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

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

        \[\leadsto 1 - \left(\log \color{blue}{\left(x + \left(-1\right)\right)} - \log y\right) \]
      4. metadata-eval98.6%

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
      5. +-commutative98.6%

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -2050000000:\\ \;\;\;\;\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)\\ \mathbf{elif}\;y \leq 38000000000000:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x \cdot \left(1 - \frac{y}{x}\right)}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 + \left(\log y - \log \left(x + -1\right)\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 91.3% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{x - y}{1 - y} \leq 0.9999995:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(1 + \frac{-1}{y}\right) + \log \left(-y\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (/ (- x y) (- 1.0 y)) 0.9999995)
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))
   (+ (+ 1.0 (/ -1.0 y)) (log (- y)))))
double code(double x, double y) {
	double tmp;
	if (((x - y) / (1.0 - y)) <= 0.9999995) {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 + (-1.0 / y)) + log(-y);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (((x - y) / (1.0 - y)) <= 0.9999995) {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	} else {
		tmp = (1.0 + (-1.0 / y)) + Math.log(-y);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if ((x - y) / (1.0 - y)) <= 0.9999995:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	else:
		tmp = (1.0 + (-1.0 / y)) + math.log(-y)
	return tmp
function code(x, y)
	tmp = 0.0
	if (Float64(Float64(x - y) / Float64(1.0 - y)) <= 0.9999995)
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	else
		tmp = Float64(Float64(1.0 + Float64(-1.0 / y)) + log(Float64(-y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[N[(N[(x - y), $MachinePrecision] / N[(1.0 - y), $MachinePrecision]), $MachinePrecision], 0.9999995], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(1.0 + N[(-1.0 / y), $MachinePrecision]), $MachinePrecision] + N[Log[(-y)], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\frac{x - y}{1 - y} \leq 0.9999995:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\

\mathbf{else}:\\
\;\;\;\;\left(1 + \frac{-1}{y}\right) + \log \left(-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)) < 0.999999500000000041

    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 0.999999500000000041 < (/.f64 (-.f64 x y) (-.f64 #s(literal 1 binary64) y))

    1. Initial program 4.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg4.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define4.6%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac24.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub04.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-4.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval4.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative4.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified4.6%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 4.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-1 \cdot \frac{y}{y - 1}}\right) \]
    6. Step-by-step derivation
      1. mul-1-neg4.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-\frac{y}{y - 1}}\right) \]
      2. sub-neg4.2%

        \[\leadsto 1 - \mathsf{log1p}\left(-\frac{y}{\color{blue}{y + \left(-1\right)}}\right) \]
      3. metadata-eval4.2%

        \[\leadsto 1 - \mathsf{log1p}\left(-\frac{y}{y + \color{blue}{-1}}\right) \]
      4. distribute-neg-frac4.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{-y}{y + -1}}\right) \]
    7. Simplified4.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{-y}{y + -1}}\right) \]
    8. Taylor expanded in y around -inf 70.9%

      \[\leadsto \color{blue}{1 - \left(\log \left(\frac{-1}{y}\right) + \frac{1}{y}\right)} \]
    9. Step-by-step derivation
      1. associate--r+71.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(\frac{-1}{y}\right)\right) - \frac{1}{y}} \]
      2. sub-neg71.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(\frac{-1}{y}\right)\right) + \left(-\frac{1}{y}\right)} \]
      3. distribute-neg-frac71.0%

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

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

      \[\leadsto \color{blue}{\left(1 - \log \left(\frac{-1}{y}\right)\right) + \frac{-1}{y}} \]
    11. Step-by-step derivation
      1. *-un-lft-identity71.0%

        \[\leadsto \color{blue}{1 \cdot \left(\left(1 - \log \left(\frac{-1}{y}\right)\right) + \frac{-1}{y}\right)} \]
      2. +-commutative71.0%

        \[\leadsto 1 \cdot \color{blue}{\left(\frac{-1}{y} + \left(1 - \log \left(\frac{-1}{y}\right)\right)\right)} \]
      3. sub-neg71.0%

        \[\leadsto 1 \cdot \left(\frac{-1}{y} + \color{blue}{\left(1 + \left(-\log \left(\frac{-1}{y}\right)\right)\right)}\right) \]
      4. associate-+r+71.0%

        \[\leadsto 1 \cdot \color{blue}{\left(\left(\frac{-1}{y} + 1\right) + \left(-\log \left(\frac{-1}{y}\right)\right)\right)} \]
      5. neg-log71.0%

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)}\right) \]
      6. clear-num71.0%

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \color{blue}{\left(\frac{y}{-1}\right)}\right) \]
      7. div-inv71.0%

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

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \left(y \cdot \color{blue}{-1}\right)\right) \]
    12. Applied egg-rr71.0%

      \[\leadsto \color{blue}{1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \left(y \cdot -1\right)\right)} \]
    13. Step-by-step derivation
      1. *-lft-identity71.0%

        \[\leadsto \color{blue}{\left(\frac{-1}{y} + 1\right) + \log \left(y \cdot -1\right)} \]
      2. +-commutative71.0%

        \[\leadsto \color{blue}{\left(1 + \frac{-1}{y}\right)} + \log \left(y \cdot -1\right) \]
      3. *-commutative71.0%

        \[\leadsto \left(1 + \frac{-1}{y}\right) + \log \color{blue}{\left(-1 \cdot y\right)} \]
      4. neg-mul-171.0%

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

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

Alternative 5: 85.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -21:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \left(y + \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -21.0)
   (+ 1.0 (log (- 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 <= -21.0) {
		tmp = 1.0 + log(-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 <= -21.0) {
		tmp = 1.0 + Math.log(-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 <= -21.0:
		tmp = 1.0 + math.log(-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 <= -21.0)
		tmp = Float64(1.0 + log(Float64(-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, -21.0], N[(1.0 + N[Log[(-y)], $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 -21:\\
\;\;\;\;1 + \log \left(-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 < -21

    1. Initial program 28.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg28.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define28.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac228.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub028.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-28.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval28.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative28.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified28.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 97.7%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+97.7%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg97.7%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval97.7%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in97.7%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval97.7%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative97.7%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define97.7%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg97.7%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified97.7%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 66.5%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg66.5%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log66.5%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num66.5%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv66.5%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval66.5%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr66.5%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative66.5%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. mul-1-neg66.5%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified66.5%

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

    if -21 < 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 99.7%

      \[\leadsto 1 - \color{blue}{\left(\log \left(1 + -1 \cdot x\right) + y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right)\right)} \]
    6. Step-by-step derivation
      1. +-commutative99.7%

        \[\leadsto 1 - \color{blue}{\left(y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right) + \log \left(1 + -1 \cdot x\right)\right)} \]
      2. div-sub99.7%

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

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

        \[\leadsto 1 - \left(y \cdot \frac{1 - x}{\color{blue}{1 - x}} + \log \left(1 + -1 \cdot x\right)\right) \]
      5. *-inverses99.7%

        \[\leadsto 1 - \left(y \cdot \color{blue}{1} + \log \left(1 + -1 \cdot x\right)\right) \]
      6. *-rgt-identity99.7%

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

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

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

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

    if 1 < y

    1. Initial program 42.5%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg42.5%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define42.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac242.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub042.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-42.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval42.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative42.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified42.5%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 45.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 42.6%

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

Alternative 6: 85.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7500000:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7500000.0)
   (+ 1.0 (log (- y)))
   (if (<= y 1.0) (- 1.0 (log1p (- x))) (- 1.0 (log1p (/ x y))))))
double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = 1.0 + log(-y);
	} else if (y <= 1.0) {
		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 <= -7500000.0) {
		tmp = 1.0 + Math.log(-y);
	} else if (y <= 1.0) {
		tmp = 1.0 - Math.log1p(-x);
	} else {
		tmp = 1.0 - Math.log1p((x / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -7500000.0:
		tmp = 1.0 + math.log(-y)
	elif y <= 1.0:
		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 <= -7500000.0)
		tmp = Float64(1.0 + log(Float64(-y)));
	elseif (y <= 1.0)
		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, -7500000.0], N[(1.0 + N[Log[(-y)], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.0], 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 -7500000:\\
\;\;\;\;1 + \log \left(-y\right)\\

\mathbf{elif}\;y \leq 1:\\
\;\;\;\;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 < -7.5e6

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.4%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+99.4%

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

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

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

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

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative99.4%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define99.4%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg99.4%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified99.4%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 68.6%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg68.6%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log68.6%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num68.6%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv68.6%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval68.6%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr68.6%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative68.6%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. mul-1-neg68.6%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified68.6%

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

    if -7.5e6 < 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 96.9%

      \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
    6. Step-by-step derivation
      1. log1p-define96.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
      2. mul-1-neg96.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
    7. Simplified96.9%

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

    if 1 < y

    1. Initial program 42.5%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg42.5%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define42.5%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac242.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub042.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-42.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval42.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative42.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified42.5%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 45.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in y around inf 42.6%

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

Alternative 7: 85.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -12500000:\\ \;\;\;\;\left(1 + \frac{-1}{y}\right) + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -12500000.0)
   (+ (+ 1.0 (/ -1.0 y)) (log (- y)))
   (- 1.0 (log1p (/ x (+ y -1.0))))))
double code(double x, double y) {
	double tmp;
	if (y <= -12500000.0) {
		tmp = (1.0 + (-1.0 / y)) + log(-y);
	} else {
		tmp = 1.0 - log1p((x / (y + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -12500000.0) {
		tmp = (1.0 + (-1.0 / y)) + Math.log(-y);
	} else {
		tmp = 1.0 - Math.log1p((x / (y + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -12500000.0:
		tmp = (1.0 + (-1.0 / y)) + math.log(-y)
	else:
		tmp = 1.0 - math.log1p((x / (y + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -12500000.0)
		tmp = Float64(Float64(1.0 + Float64(-1.0 / y)) + log(Float64(-y)));
	else
		tmp = Float64(1.0 - log1p(Float64(x / Float64(y + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -12500000.0], N[(N[(1.0 + N[(-1.0 / y), $MachinePrecision]), $MachinePrecision] + N[Log[(-y)], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -12500000:\\
\;\;\;\;\left(1 + \frac{-1}{y}\right) + \log \left(-y\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -1.25e7

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around 0 3.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-1 \cdot \frac{y}{y - 1}}\right) \]
    6. Step-by-step derivation
      1. mul-1-neg3.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-\frac{y}{y - 1}}\right) \]
      2. sub-neg3.6%

        \[\leadsto 1 - \mathsf{log1p}\left(-\frac{y}{\color{blue}{y + \left(-1\right)}}\right) \]
      3. metadata-eval3.6%

        \[\leadsto 1 - \mathsf{log1p}\left(-\frac{y}{y + \color{blue}{-1}}\right) \]
      4. distribute-neg-frac3.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{-y}{y + -1}}\right) \]
    7. Simplified3.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{-y}{y + -1}}\right) \]
    8. Taylor expanded in y around -inf 68.7%

      \[\leadsto \color{blue}{1 - \left(\log \left(\frac{-1}{y}\right) + \frac{1}{y}\right)} \]
    9. Step-by-step derivation
      1. associate--r+68.7%

        \[\leadsto \color{blue}{\left(1 - \log \left(\frac{-1}{y}\right)\right) - \frac{1}{y}} \]
      2. sub-neg68.7%

        \[\leadsto \color{blue}{\left(1 - \log \left(\frac{-1}{y}\right)\right) + \left(-\frac{1}{y}\right)} \]
      3. distribute-neg-frac68.7%

        \[\leadsto \left(1 - \log \left(\frac{-1}{y}\right)\right) + \color{blue}{\frac{-1}{y}} \]
      4. metadata-eval68.7%

        \[\leadsto \left(1 - \log \left(\frac{-1}{y}\right)\right) + \frac{\color{blue}{-1}}{y} \]
    10. Simplified68.7%

      \[\leadsto \color{blue}{\left(1 - \log \left(\frac{-1}{y}\right)\right) + \frac{-1}{y}} \]
    11. Step-by-step derivation
      1. *-un-lft-identity68.7%

        \[\leadsto \color{blue}{1 \cdot \left(\left(1 - \log \left(\frac{-1}{y}\right)\right) + \frac{-1}{y}\right)} \]
      2. +-commutative68.7%

        \[\leadsto 1 \cdot \color{blue}{\left(\frac{-1}{y} + \left(1 - \log \left(\frac{-1}{y}\right)\right)\right)} \]
      3. sub-neg68.7%

        \[\leadsto 1 \cdot \left(\frac{-1}{y} + \color{blue}{\left(1 + \left(-\log \left(\frac{-1}{y}\right)\right)\right)}\right) \]
      4. associate-+r+68.7%

        \[\leadsto 1 \cdot \color{blue}{\left(\left(\frac{-1}{y} + 1\right) + \left(-\log \left(\frac{-1}{y}\right)\right)\right)} \]
      5. neg-log68.7%

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)}\right) \]
      6. clear-num68.7%

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \color{blue}{\left(\frac{y}{-1}\right)}\right) \]
      7. div-inv68.7%

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)}\right) \]
      8. metadata-eval68.7%

        \[\leadsto 1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \left(y \cdot \color{blue}{-1}\right)\right) \]
    12. Applied egg-rr68.7%

      \[\leadsto \color{blue}{1 \cdot \left(\left(\frac{-1}{y} + 1\right) + \log \left(y \cdot -1\right)\right)} \]
    13. Step-by-step derivation
      1. *-lft-identity68.7%

        \[\leadsto \color{blue}{\left(\frac{-1}{y} + 1\right) + \log \left(y \cdot -1\right)} \]
      2. +-commutative68.7%

        \[\leadsto \color{blue}{\left(1 + \frac{-1}{y}\right)} + \log \left(y \cdot -1\right) \]
      3. *-commutative68.7%

        \[\leadsto \left(1 + \frac{-1}{y}\right) + \log \color{blue}{\left(-1 \cdot y\right)} \]
      4. neg-mul-168.7%

        \[\leadsto \left(1 + \frac{-1}{y}\right) + \log \color{blue}{\left(-y\right)} \]
    14. Simplified68.7%

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

    if -1.25e7 < y

    1. Initial program 92.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg92.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define92.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac292.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub092.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified92.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 91.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification84.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -12500000:\\ \;\;\;\;\left(1 + \frac{-1}{y}\right) + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 85.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -100000000000:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -100000000000.0)
   (+ 1.0 (log (- y)))
   (- 1.0 (log1p (/ x (+ y -1.0))))))
double code(double x, double y) {
	double tmp;
	if (y <= -100000000000.0) {
		tmp = 1.0 + log(-y);
	} else {
		tmp = 1.0 - log1p((x / (y + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -100000000000.0) {
		tmp = 1.0 + Math.log(-y);
	} else {
		tmp = 1.0 - Math.log1p((x / (y + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -100000000000.0:
		tmp = 1.0 + math.log(-y)
	else:
		tmp = 1.0 - math.log1p((x / (y + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -100000000000.0)
		tmp = Float64(1.0 + log(Float64(-y)));
	else
		tmp = Float64(1.0 - log1p(Float64(x / Float64(y + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -100000000000.0], N[(1.0 + N[Log[(-y)], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -100000000000:\\
\;\;\;\;1 + \log \left(-y\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -1e11

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.4%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+99.4%

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

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

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

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

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative99.4%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define99.4%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg99.4%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified99.4%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 68.6%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg68.6%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log68.6%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num68.6%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv68.6%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval68.6%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr68.6%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative68.6%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. mul-1-neg68.6%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified68.6%

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

    if -1e11 < y

    1. Initial program 92.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg92.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define92.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac292.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub092.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified92.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 91.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification84.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -100000000000:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 79.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7500000:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7500000.0) (+ 1.0 (log (- y))) (- 1.0 (log1p (- x)))))
double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = 1.0 + log(-y);
	} else {
		tmp = 1.0 - log1p(-x);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -7500000.0) {
		tmp = 1.0 + Math.log(-y);
	} else {
		tmp = 1.0 - Math.log1p(-x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -7500000.0:
		tmp = 1.0 + math.log(-y)
	else:
		tmp = 1.0 - math.log1p(-x)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -7500000.0)
		tmp = Float64(1.0 + log(Float64(-y)));
	else
		tmp = Float64(1.0 - log1p(Float64(-x)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -7500000.0], N[(1.0 + N[Log[(-y)], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -7500000:\\
\;\;\;\;1 + \log \left(-y\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -7.5e6

    1. Initial program 25.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg25.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define25.7%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac225.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub025.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-25.7%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval25.7%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified25.7%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 99.4%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+99.4%

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

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

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

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

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative99.4%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define99.4%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg99.4%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified99.4%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 68.6%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg68.6%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log68.6%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num68.6%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv68.6%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval68.6%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr68.6%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative68.6%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. mul-1-neg68.6%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified68.6%

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

    if -7.5e6 < y

    1. Initial program 92.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg92.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define92.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac292.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub092.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative92.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified92.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 83.8%

      \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
    6. Step-by-step derivation
      1. log1p-define83.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
      2. mul-1-neg83.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
    7. Simplified83.9%

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

Alternative 10: 61.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.42:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{x}{y + -1}\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1.42) (+ 1.0 (log (- y))) (- 1.0 (/ x (+ y -1.0)))))
double code(double x, double y) {
	double tmp;
	if (y <= -1.42) {
		tmp = 1.0 + log(-y);
	} else {
		tmp = 1.0 - (x / (y + -1.0));
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (y <= (-1.42d0)) then
        tmp = 1.0d0 + log(-y)
    else
        tmp = 1.0d0 - (x / (y + (-1.0d0)))
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if (y <= -1.42) {
		tmp = 1.0 + Math.log(-y);
	} else {
		tmp = 1.0 - (x / (y + -1.0));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1.42:
		tmp = 1.0 + math.log(-y)
	else:
		tmp = 1.0 - (x / (y + -1.0))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1.42)
		tmp = Float64(1.0 + log(Float64(-y)));
	else
		tmp = Float64(1.0 - Float64(x / Float64(y + -1.0)));
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (y <= -1.42)
		tmp = 1.0 + log(-y);
	else
		tmp = 1.0 - (x / (y + -1.0));
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[y, -1.42], N[(1.0 + N[Log[(-y)], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.42:\\
\;\;\;\;1 + \log \left(-y\right)\\

\mathbf{else}:\\
\;\;\;\;1 - \frac{x}{y + -1}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -1.4199999999999999

    1. Initial program 28.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg28.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define28.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac228.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub028.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-28.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval28.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative28.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified28.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 97.7%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+97.7%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg97.7%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval97.7%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in97.7%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval97.7%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative97.7%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define97.7%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg97.7%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified97.7%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 66.5%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg66.5%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log66.5%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num66.5%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv66.5%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval66.5%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr66.5%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative66.5%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. mul-1-neg66.5%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified66.5%

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

    if -1.4199999999999999 < y

    1. Initial program 92.1%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg92.1%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define92.1%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac292.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub092.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-92.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval92.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative92.1%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified92.1%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 91.5%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in x around 0 57.0%

      \[\leadsto 1 - \color{blue}{\frac{x}{y - 1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification60.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1.42:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{x}{y + -1}\\ \end{array} \]
  5. Add Preprocessing

Alternative 11: 45.2% 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 71.9%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define72.0%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac272.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub072.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified72.0%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 72.9%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 42.9%

    \[\leadsto 1 - \color{blue}{\frac{x}{y - 1}} \]
  7. Final simplification42.9%

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

Alternative 12: 43.8% accurate, 37.0× speedup?

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

\\
x + 1
\end{array}
Derivation
  1. Initial program 71.9%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define72.0%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac272.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub072.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified72.0%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 62.4%

    \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define62.4%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg62.4%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified62.4%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(-x\right)} \]
  8. Taylor expanded in x around 0 41.6%

    \[\leadsto \color{blue}{1 + x} \]
  9. Final simplification41.6%

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

Alternative 13: 43.5% 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 71.9%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg71.9%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define72.0%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac272.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub072.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified72.0%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 72.9%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 41.1%

    \[\leadsto \color{blue}{1} \]
  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 2024165 
(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))))))