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

Percentage Accurate: 75.2% → 96.0%
Time: 11.4s
Alternatives: 12
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 12 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: 75.2% 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: 96.0% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -235000:\\ \;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -235000.0)
   (+ 1.0 (- (- (/ -1.0 y) (log (/ -1.0 y))) (log1p (- x))))
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))))
double code(double x, double y) {
	double tmp;
	if (y <= -235000.0) {
		tmp = 1.0 + (((-1.0 / y) - log((-1.0 / y))) - log1p(-x));
	} else {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -235000.0) {
		tmp = 1.0 + (((-1.0 / y) - Math.log((-1.0 / y))) - Math.log1p(-x));
	} else {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -235000.0:
		tmp = 1.0 + (((-1.0 / y) - math.log((-1.0 / y))) - math.log1p(-x))
	else:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -235000.0)
		tmp = Float64(1.0 + Float64(Float64(Float64(-1.0 / y) - log(Float64(-1.0 / y))) - log1p(Float64(-x))));
	else
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -235000.0], 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], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -235000:\\
\;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -235000

    1. Initial program 17.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg17.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define17.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac217.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub017.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified17.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 98.1%

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

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

    if -235000 < y

    1. Initial program 94.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg94.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define94.6%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac294.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub094.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-94.6%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative94.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified94.6%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification95.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -235000:\\ \;\;\;\;1 + \left(\left(\frac{-1}{y} - \log \left(\frac{-1}{y}\right)\right) - \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 90.4% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 1 - \log \left(\frac{x + -1}{y}\right)\\ \mathbf{if}\;y \leq -1.65:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \left(y + \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{elif}\;y \leq 3.4 \cdot 10^{+160}:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (- 1.0 (log (/ (+ x -1.0) y)))))
   (if (<= y -1.65)
     t_0
     (if (<= y 1.0)
       (- 1.0 (+ y (log1p (- x))))
       (if (<= y 3.4e+160) t_0 (- 1.0 (log1p -1.0)))))))
double code(double x, double y) {
	double t_0 = 1.0 - log(((x + -1.0) / y));
	double tmp;
	if (y <= -1.65) {
		tmp = t_0;
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + log1p(-x));
	} else if (y <= 3.4e+160) {
		tmp = t_0;
	} else {
		tmp = 1.0 - log1p(-1.0);
	}
	return tmp;
}
public static double code(double x, double y) {
	double t_0 = 1.0 - Math.log(((x + -1.0) / y));
	double tmp;
	if (y <= -1.65) {
		tmp = t_0;
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + Math.log1p(-x));
	} else if (y <= 3.4e+160) {
		tmp = t_0;
	} else {
		tmp = 1.0 - Math.log1p(-1.0);
	}
	return tmp;
}
def code(x, y):
	t_0 = 1.0 - math.log(((x + -1.0) / y))
	tmp = 0
	if y <= -1.65:
		tmp = t_0
	elif y <= 1.0:
		tmp = 1.0 - (y + math.log1p(-x))
	elif y <= 3.4e+160:
		tmp = t_0
	else:
		tmp = 1.0 - math.log1p(-1.0)
	return tmp
function code(x, y)
	t_0 = Float64(1.0 - log(Float64(Float64(x + -1.0) / y)))
	tmp = 0.0
	if (y <= -1.65)
		tmp = t_0;
	elseif (y <= 1.0)
		tmp = Float64(1.0 - Float64(y + log1p(Float64(-x))));
	elseif (y <= 3.4e+160)
		tmp = t_0;
	else
		tmp = Float64(1.0 - log1p(-1.0));
	end
	return tmp
end
code[x_, y_] := Block[{t$95$0 = N[(1.0 - N[Log[N[(N[(x + -1.0), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[y, -1.65], t$95$0, If[LessEqual[y, 1.0], N[(1.0 - N[(y + N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 3.4e+160], t$95$0, N[(1.0 - N[Log[1 + -1.0], $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 1 - \log \left(\frac{x + -1}{y}\right)\\
\mathbf{if}\;y \leq -1.65:\\
\;\;\;\;t\_0\\

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

\mathbf{elif}\;y \leq 3.4 \cdot 10^{+160}:\\
\;\;\;\;t\_0\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1.6499999999999999 or 1 < y < 3.4000000000000003e160

    1. Initial program 29.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg29.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define29.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac229.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub029.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-29.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval29.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative29.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified29.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. clear-num29.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{\frac{y + -1}{x - y}}}\right) \]
      2. associate-/r/30.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    6. Applied egg-rr30.8%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    7. Taylor expanded in y around inf 12.8%

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    8. Step-by-step derivation
      1. log-rec12.8%

        \[\leadsto 1 - \left(\log \left(x - 1\right) + \color{blue}{\left(-\log y\right)}\right) \]
      2. unsub-neg12.8%

        \[\leadsto 1 - \color{blue}{\left(\log \left(x - 1\right) - \log y\right)} \]
      3. sub-neg12.8%

        \[\leadsto 1 - \left(\log \color{blue}{\left(x + \left(-1\right)\right)} - \log y\right) \]
      4. metadata-eval12.8%

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
    9. Simplified12.8%

      \[\leadsto \color{blue}{1 - \left(\log \left(x + -1\right) - \log y\right)} \]
    10. Step-by-step derivation
      1. diff-log90.0%

        \[\leadsto 1 - \color{blue}{\log \left(\frac{x + -1}{y}\right)} \]
    11. Applied egg-rr90.0%

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

    if -1.6499999999999999 < 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 99.8%

      \[\leadsto 1 - \color{blue}{\left(\log \left(1 + -1 \cdot x\right) + y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right)\right)} \]
    6. Step-by-step derivation
      1. +-commutative99.8%

        \[\leadsto 1 - \color{blue}{\left(y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right) + \log \left(1 + -1 \cdot x\right)\right)} \]
      2. div-sub99.8%

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

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

        \[\leadsto 1 - \left(y \cdot \frac{1 - x}{\color{blue}{1 - x}} + \log \left(1 + -1 \cdot x\right)\right) \]
      5. *-inverses99.8%

        \[\leadsto 1 - \left(y \cdot \color{blue}{1} + \log \left(1 + -1 \cdot x\right)\right) \]
      6. *-rgt-identity99.8%

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

        \[\leadsto 1 - \left(y + \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) \]
      8. mul-1-neg99.9%

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

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

    if 3.4000000000000003e160 < y

    1. Initial program 81.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg81.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define81.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac281.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub081.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-81.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval81.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative81.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified81.4%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 77.6%

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

Alternative 3: 95.1% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.65:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \left(y + \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1.65)
   (- 1.0 (log (/ (+ x -1.0) y)))
   (if (<= y 1.0) (- 1.0 (+ y (log1p (- x)))) (- 1.0 (log1p (/ (- x y) y))))))
double code(double x, double y) {
	double tmp;
	if (y <= -1.65) {
		tmp = 1.0 - log(((x + -1.0) / y));
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + log1p(-x));
	} else {
		tmp = 1.0 - log1p(((x - y) / y));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1.65) {
		tmp = 1.0 - Math.log(((x + -1.0) / y));
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + Math.log1p(-x));
	} else {
		tmp = 1.0 - Math.log1p(((x - y) / y));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1.65:
		tmp = 1.0 - math.log(((x + -1.0) / y))
	elif y <= 1.0:
		tmp = 1.0 - (y + math.log1p(-x))
	else:
		tmp = 1.0 - math.log1p(((x - y) / y))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1.65)
		tmp = Float64(1.0 - log(Float64(Float64(x + -1.0) / y)));
	elseif (y <= 1.0)
		tmp = Float64(1.0 - Float64(y + log1p(Float64(-x))));
	else
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / y)));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1.65], N[(1.0 - N[Log[N[(N[(x + -1.0), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.0], N[(1.0 - N[(y + N[Log[1 + (-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.65:\\
\;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1.6499999999999999

    1. Initial program 17.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg17.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define17.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac217.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub017.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified17.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. clear-num17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{\frac{y + -1}{x - y}}}\right) \]
      2. associate-/r/19.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    6. Applied egg-rr19.0%

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

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    8. Step-by-step derivation
      1. log-rec0.0%

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

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

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

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
    9. Simplified0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(x + -1\right) - \log y\right)} \]
    10. Step-by-step derivation
      1. diff-log97.3%

        \[\leadsto 1 - \color{blue}{\log \left(\frac{x + -1}{y}\right)} \]
    11. Applied egg-rr97.3%

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

    if -1.6499999999999999 < 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 99.8%

      \[\leadsto 1 - \color{blue}{\left(\log \left(1 + -1 \cdot x\right) + y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right)\right)} \]
    6. Step-by-step derivation
      1. +-commutative99.8%

        \[\leadsto 1 - \color{blue}{\left(y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right) + \log \left(1 + -1 \cdot x\right)\right)} \]
      2. div-sub99.8%

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

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

        \[\leadsto 1 - \left(y \cdot \frac{1 - x}{\color{blue}{1 - x}} + \log \left(1 + -1 \cdot x\right)\right) \]
      5. *-inverses99.8%

        \[\leadsto 1 - \left(y \cdot \color{blue}{1} + \log \left(1 + -1 \cdot x\right)\right) \]
      6. *-rgt-identity99.8%

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

        \[\leadsto 1 - \left(y + \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) \]
      8. mul-1-neg99.9%

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

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

    if 1 < y

    1. Initial program 78.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg78.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define78.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac278.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub078.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified78.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 77.8%

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

Alternative 4: 91.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1060:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \mathbf{elif}\;y \leq 1.25 \cdot 10^{+49}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1060.0)
   (- 1.0 (log (/ (+ x -1.0) y)))
   (if (<= y 1.25e+49) (- 1.0 (log1p (/ x (+ y -1.0)))) (- 1.0 (log1p -1.0)))))
double code(double x, double y) {
	double tmp;
	if (y <= -1060.0) {
		tmp = 1.0 - log(((x + -1.0) / y));
	} else if (y <= 1.25e+49) {
		tmp = 1.0 - log1p((x / (y + -1.0)));
	} else {
		tmp = 1.0 - log1p(-1.0);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1060.0) {
		tmp = 1.0 - Math.log(((x + -1.0) / y));
	} else if (y <= 1.25e+49) {
		tmp = 1.0 - Math.log1p((x / (y + -1.0)));
	} else {
		tmp = 1.0 - Math.log1p(-1.0);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1060.0:
		tmp = 1.0 - math.log(((x + -1.0) / y))
	elif y <= 1.25e+49:
		tmp = 1.0 - math.log1p((x / (y + -1.0)))
	else:
		tmp = 1.0 - math.log1p(-1.0)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1060.0)
		tmp = Float64(1.0 - log(Float64(Float64(x + -1.0) / y)));
	elseif (y <= 1.25e+49)
		tmp = Float64(1.0 - log1p(Float64(x / Float64(y + -1.0))));
	else
		tmp = Float64(1.0 - log1p(-1.0));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1060.0], N[(1.0 - N[Log[N[(N[(x + -1.0), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 1.25e+49], N[(1.0 - N[Log[1 + N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + -1.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1060:\\
\;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\

\mathbf{elif}\;y \leq 1.25 \cdot 10^{+49}:\\
\;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1060

    1. Initial program 17.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg17.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define17.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac217.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub017.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified17.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. clear-num17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{\frac{y + -1}{x - y}}}\right) \]
      2. associate-/r/19.0%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    6. Applied egg-rr19.0%

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

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    8. Step-by-step derivation
      1. log-rec0.0%

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

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

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

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
    9. Simplified0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(x + -1\right) - \log y\right)} \]
    10. Step-by-step derivation
      1. diff-log97.3%

        \[\leadsto 1 - \color{blue}{\log \left(\frac{x + -1}{y}\right)} \]
    11. Applied egg-rr97.3%

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

    if -1060 < y < 1.2500000000000001e49

    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 98.4%

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

    if 1.2500000000000001e49 < y

    1. Initial program 75.8%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg75.8%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define75.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac275.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub075.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-75.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval75.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative75.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified75.8%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 65.9%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-1}\right) \]
  3. Recombined 3 regimes into one program.
  4. Final simplification93.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1060:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \mathbf{elif}\;y \leq 1.25 \cdot 10^{+49}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x}{y + -1}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 82.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -16.5:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \left(y + \mathsf{log1p}\left(-x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -16.5)
   (+ 1.0 (log (- y)))
   (if (<= y 1.0) (- 1.0 (+ y (log1p (- x)))) (- 1.0 (log1p -1.0)))))
double code(double x, double y) {
	double tmp;
	if (y <= -16.5) {
		tmp = 1.0 + log(-y);
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + log1p(-x));
	} else {
		tmp = 1.0 - log1p(-1.0);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -16.5) {
		tmp = 1.0 + Math.log(-y);
	} else if (y <= 1.0) {
		tmp = 1.0 - (y + Math.log1p(-x));
	} else {
		tmp = 1.0 - Math.log1p(-1.0);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -16.5:
		tmp = 1.0 + math.log(-y)
	elif y <= 1.0:
		tmp = 1.0 - (y + math.log1p(-x))
	else:
		tmp = 1.0 - math.log1p(-1.0)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -16.5)
		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(-1.0));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -16.5], 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 + -1.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -16.5:\\
\;\;\;\;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(-1\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -16.5

    1. Initial program 17.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg17.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define17.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac217.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub017.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified17.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 97.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+97.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in97.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative97.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define97.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg97.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified97.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 72.0%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg72.0%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log72.0%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num72.0%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv72.0%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval72.0%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr72.0%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative72.0%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. neg-mul-172.0%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified72.0%

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

    if -16.5 < 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 99.8%

      \[\leadsto 1 - \color{blue}{\left(\log \left(1 + -1 \cdot x\right) + y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right)\right)} \]
    6. Step-by-step derivation
      1. +-commutative99.8%

        \[\leadsto 1 - \color{blue}{\left(y \cdot \left(\frac{1}{1 + -1 \cdot x} - \frac{x}{1 + -1 \cdot x}\right) + \log \left(1 + -1 \cdot x\right)\right)} \]
      2. div-sub99.8%

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

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

        \[\leadsto 1 - \left(y \cdot \frac{1 - x}{\color{blue}{1 - x}} + \log \left(1 + -1 \cdot x\right)\right) \]
      5. *-inverses99.8%

        \[\leadsto 1 - \left(y \cdot \color{blue}{1} + \log \left(1 + -1 \cdot x\right)\right) \]
      6. *-rgt-identity99.8%

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

        \[\leadsto 1 - \left(y + \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) \]
      8. mul-1-neg99.9%

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

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

    if 1 < y

    1. Initial program 78.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg78.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define78.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac278.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub078.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified78.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 59.6%

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

Alternative 6: 81.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -2.9:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{elif}\;y \leq 1:\\ \;\;\;\;1 - \mathsf{log1p}\left(-x\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -2.9)
   (+ 1.0 (log (- y)))
   (if (<= y 1.0) (- 1.0 (log1p (- x))) (- 1.0 (log1p -1.0)))))
double code(double x, double y) {
	double tmp;
	if (y <= -2.9) {
		tmp = 1.0 + log(-y);
	} else if (y <= 1.0) {
		tmp = 1.0 - log1p(-x);
	} else {
		tmp = 1.0 - log1p(-1.0);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -2.9) {
		tmp = 1.0 + Math.log(-y);
	} else if (y <= 1.0) {
		tmp = 1.0 - Math.log1p(-x);
	} else {
		tmp = 1.0 - Math.log1p(-1.0);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -2.9:
		tmp = 1.0 + math.log(-y)
	elif y <= 1.0:
		tmp = 1.0 - math.log1p(-x)
	else:
		tmp = 1.0 - math.log1p(-1.0)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -2.9)
		tmp = Float64(1.0 + log(Float64(-y)));
	elseif (y <= 1.0)
		tmp = Float64(1.0 - log1p(Float64(-x)));
	else
		tmp = Float64(1.0 - log1p(-1.0));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -2.9], 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 + -1.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -2.9:\\
\;\;\;\;1 + \log \left(-y\right)\\

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

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -2.89999999999999991

    1. Initial program 17.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg17.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define17.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac217.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub017.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified17.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 97.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+97.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in97.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative97.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define97.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg97.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified97.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 72.0%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg72.0%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log72.0%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num72.0%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv72.0%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval72.0%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr72.0%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative72.0%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. neg-mul-172.0%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified72.0%

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

    if -2.89999999999999991 < y < 1

    1. Initial program 99.9%

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

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

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

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

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

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

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

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

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around 0 98.8%

      \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
    6. Step-by-step derivation
      1. log1p-define98.8%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
      2. mul-1-neg98.8%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
    7. Simplified98.8%

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

    if 1 < y

    1. Initial program 78.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg78.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define78.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac278.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub078.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative78.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified78.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 59.6%

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

Alternative 7: 96.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -3200000000:\\ \;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -3200000000.0)
   (- 1.0 (log (/ (+ x -1.0) y)))
   (- 1.0 (log1p (/ (- x y) (+ y -1.0))))))
double code(double x, double y) {
	double tmp;
	if (y <= -3200000000.0) {
		tmp = 1.0 - log(((x + -1.0) / y));
	} else {
		tmp = 1.0 - log1p(((x - y) / (y + -1.0)));
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -3200000000.0) {
		tmp = 1.0 - Math.log(((x + -1.0) / y));
	} else {
		tmp = 1.0 - Math.log1p(((x - y) / (y + -1.0)));
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -3200000000.0:
		tmp = 1.0 - math.log(((x + -1.0) / y))
	else:
		tmp = 1.0 - math.log1p(((x - y) / (y + -1.0)))
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -3200000000.0)
		tmp = Float64(1.0 - log(Float64(Float64(x + -1.0) / y)));
	else
		tmp = Float64(1.0 - log1p(Float64(Float64(x - y) / Float64(y + -1.0))));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -3200000000.0], N[(1.0 - N[Log[N[(N[(x + -1.0), $MachinePrecision] / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + N[(N[(x - y), $MachinePrecision] / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -3200000000:\\
\;\;\;\;1 - \log \left(\frac{x + -1}{y}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -3.2e9

    1. Initial program 15.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg15.6%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define15.6%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac215.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub015.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-15.6%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative15.6%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified15.6%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Step-by-step derivation
      1. clear-num15.5%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{\frac{y + -1}{x - y}}}\right) \]
      2. associate-/r/17.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{1}{y + -1} \cdot \left(x - y\right)}\right) \]
    6. Applied egg-rr17.4%

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

      \[\leadsto \color{blue}{1 - \left(\log \left(x - 1\right) + \log \left(\frac{1}{y}\right)\right)} \]
    8. Step-by-step derivation
      1. log-rec0.0%

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

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

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

        \[\leadsto 1 - \left(\log \left(x + \color{blue}{-1}\right) - \log y\right) \]
    9. Simplified0.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(x + -1\right) - \log y\right)} \]
    10. Step-by-step derivation
      1. diff-log98.4%

        \[\leadsto 1 - \color{blue}{\log \left(\frac{x + -1}{y}\right)} \]
    11. Applied egg-rr98.4%

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

    if -3.2e9 < y

    1. Initial program 94.4%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg94.4%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define94.4%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac294.4%

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

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-94.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval94.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative94.4%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified94.4%

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

Alternative 8: 63.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -1.95:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{elif}\;y \leq 7.2 \cdot 10^{+44}:\\ \;\;\;\;1 - \frac{x}{y + -1}\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -1.95)
   (+ 1.0 (log (- y)))
   (if (<= y 7.2e+44) (- 1.0 (/ x (+ y -1.0))) (- 1.0 (log1p -1.0)))))
double code(double x, double y) {
	double tmp;
	if (y <= -1.95) {
		tmp = 1.0 + log(-y);
	} else if (y <= 7.2e+44) {
		tmp = 1.0 - (x / (y + -1.0));
	} else {
		tmp = 1.0 - log1p(-1.0);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= -1.95) {
		tmp = 1.0 + Math.log(-y);
	} else if (y <= 7.2e+44) {
		tmp = 1.0 - (x / (y + -1.0));
	} else {
		tmp = 1.0 - Math.log1p(-1.0);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -1.95:
		tmp = 1.0 + math.log(-y)
	elif y <= 7.2e+44:
		tmp = 1.0 - (x / (y + -1.0))
	else:
		tmp = 1.0 - math.log1p(-1.0)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -1.95)
		tmp = Float64(1.0 + log(Float64(-y)));
	elseif (y <= 7.2e+44)
		tmp = Float64(1.0 - Float64(x / Float64(y + -1.0)));
	else
		tmp = Float64(1.0 - log1p(-1.0));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -1.95], N[(1.0 + N[Log[(-y)], $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 7.2e+44], N[(1.0 - N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + -1.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.95:\\
\;\;\;\;1 + \log \left(-y\right)\\

\mathbf{elif}\;y \leq 7.2 \cdot 10^{+44}:\\
\;\;\;\;1 - \frac{x}{y + -1}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -1.94999999999999996

    1. Initial program 17.2%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg17.2%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define17.2%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac217.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub017.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative17.2%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified17.2%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around -inf 97.0%

      \[\leadsto \color{blue}{1 - \left(\log \left(-1 \cdot \left(x - 1\right)\right) + \log \left(\frac{-1}{y}\right)\right)} \]
    6. Step-by-step derivation
      1. associate--r+97.0%

        \[\leadsto \color{blue}{\left(1 - \log \left(-1 \cdot \left(x - 1\right)\right)\right) - \log \left(\frac{-1}{y}\right)} \]
      2. sub-neg97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \color{blue}{\left(x + \left(-1\right)\right)}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      3. metadata-eval97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot \left(x + \color{blue}{-1}\right)\right)\right) - \log \left(\frac{-1}{y}\right) \]
      4. distribute-lft-in97.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(-1 \cdot x + -1 \cdot -1\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      5. metadata-eval97.0%

        \[\leadsto \left(1 - \log \left(-1 \cdot x + \color{blue}{1}\right)\right) - \log \left(\frac{-1}{y}\right) \]
      6. +-commutative97.0%

        \[\leadsto \left(1 - \log \color{blue}{\left(1 + -1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      7. log1p-define97.0%

        \[\leadsto \left(1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)}\right) - \log \left(\frac{-1}{y}\right) \]
      8. mul-1-neg97.0%

        \[\leadsto \left(1 - \mathsf{log1p}\left(\color{blue}{-x}\right)\right) - \log \left(\frac{-1}{y}\right) \]
    7. Simplified97.0%

      \[\leadsto \color{blue}{\left(1 - \mathsf{log1p}\left(-x\right)\right) - \log \left(\frac{-1}{y}\right)} \]
    8. Taylor expanded in x around 0 72.0%

      \[\leadsto \color{blue}{1 - \log \left(\frac{-1}{y}\right)} \]
    9. Step-by-step derivation
      1. sub-neg72.0%

        \[\leadsto \color{blue}{1 + \left(-\log \left(\frac{-1}{y}\right)\right)} \]
      2. neg-log72.0%

        \[\leadsto 1 + \color{blue}{\log \left(\frac{1}{\frac{-1}{y}}\right)} \]
      3. clear-num72.0%

        \[\leadsto 1 + \log \color{blue}{\left(\frac{y}{-1}\right)} \]
      4. div-inv72.0%

        \[\leadsto 1 + \log \color{blue}{\left(y \cdot \frac{1}{-1}\right)} \]
      5. metadata-eval72.0%

        \[\leadsto 1 + \log \left(y \cdot \color{blue}{-1}\right) \]
    10. Applied egg-rr72.0%

      \[\leadsto \color{blue}{1 + \log \left(y \cdot -1\right)} \]
    11. Step-by-step derivation
      1. *-commutative72.0%

        \[\leadsto 1 + \log \color{blue}{\left(-1 \cdot y\right)} \]
      2. neg-mul-172.0%

        \[\leadsto 1 + \log \color{blue}{\left(-y\right)} \]
    12. Simplified72.0%

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

    if -1.94999999999999996 < y < 7.2e44

    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 99.1%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in x around 0 62.9%

      \[\leadsto \color{blue}{1 + -1 \cdot \frac{x}{y - 1}} \]
    7. Step-by-step derivation
      1. mul-1-neg62.9%

        \[\leadsto 1 + \color{blue}{\left(-\frac{x}{y - 1}\right)} \]
      2. sub-neg62.9%

        \[\leadsto 1 + \left(-\frac{x}{\color{blue}{y + \left(-1\right)}}\right) \]
      3. metadata-eval62.9%

        \[\leadsto 1 + \left(-\frac{x}{y + \color{blue}{-1}}\right) \]
      4. unsub-neg62.9%

        \[\leadsto \color{blue}{1 - \frac{x}{y + -1}} \]
      5. +-commutative62.9%

        \[\leadsto 1 - \frac{x}{\color{blue}{-1 + y}} \]
    8. Simplified62.9%

      \[\leadsto \color{blue}{1 - \frac{x}{-1 + y}} \]

    if 7.2e44 < y

    1. Initial program 76.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg76.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define76.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac276.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub076.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-76.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval76.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative76.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified76.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 65.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-1}\right) \]
  3. Recombined 3 regimes into one program.
  4. Final simplification66.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -1.95:\\ \;\;\;\;1 + \log \left(-y\right)\\ \mathbf{elif}\;y \leq 7.2 \cdot 10^{+44}:\\ \;\;\;\;1 - \frac{x}{y + -1}\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 49.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 7.2 \cdot 10^{+44}:\\ \;\;\;\;1 - \frac{x}{y + -1}\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y 7.2e+44) (- 1.0 (/ x (+ y -1.0))) (- 1.0 (log1p -1.0))))
double code(double x, double y) {
	double tmp;
	if (y <= 7.2e+44) {
		tmp = 1.0 - (x / (y + -1.0));
	} else {
		tmp = 1.0 - log1p(-1.0);
	}
	return tmp;
}
public static double code(double x, double y) {
	double tmp;
	if (y <= 7.2e+44) {
		tmp = 1.0 - (x / (y + -1.0));
	} else {
		tmp = 1.0 - Math.log1p(-1.0);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= 7.2e+44:
		tmp = 1.0 - (x / (y + -1.0))
	else:
		tmp = 1.0 - math.log1p(-1.0)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= 7.2e+44)
		tmp = Float64(1.0 - Float64(x / Float64(y + -1.0)));
	else
		tmp = Float64(1.0 - log1p(-1.0));
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, 7.2e+44], N[(1.0 - N[(x / N[(y + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(1.0 - N[Log[1 + -1.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq 7.2 \cdot 10^{+44}:\\
\;\;\;\;1 - \frac{x}{y + -1}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 7.2e44

    1. Initial program 70.6%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg70.6%

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

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

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

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

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

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

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

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in x around inf 72.0%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
    6. Taylor expanded in x around 0 45.3%

      \[\leadsto \color{blue}{1 + -1 \cdot \frac{x}{y - 1}} \]
    7. Step-by-step derivation
      1. mul-1-neg45.3%

        \[\leadsto 1 + \color{blue}{\left(-\frac{x}{y - 1}\right)} \]
      2. sub-neg45.3%

        \[\leadsto 1 + \left(-\frac{x}{\color{blue}{y + \left(-1\right)}}\right) \]
      3. metadata-eval45.3%

        \[\leadsto 1 + \left(-\frac{x}{y + \color{blue}{-1}}\right) \]
      4. unsub-neg45.3%

        \[\leadsto \color{blue}{1 - \frac{x}{y + -1}} \]
      5. +-commutative45.3%

        \[\leadsto 1 - \frac{x}{\color{blue}{-1 + y}} \]
    8. Simplified45.3%

      \[\leadsto \color{blue}{1 - \frac{x}{-1 + y}} \]

    if 7.2e44 < y

    1. Initial program 76.9%

      \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
    2. Step-by-step derivation
      1. sub-neg76.9%

        \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
      2. log1p-define76.9%

        \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
      3. distribute-neg-frac276.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
      4. neg-sub076.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
      5. associate--r-76.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
      6. metadata-eval76.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
      7. +-commutative76.9%

        \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
    3. Simplified76.9%

      \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
    4. Add Preprocessing
    5. Taylor expanded in y around inf 65.2%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-1}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification48.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 7.2 \cdot 10^{+44}:\\ \;\;\;\;1 - \frac{x}{y + -1}\\ \mathbf{else}:\\ \;\;\;\;1 - \mathsf{log1p}\left(-1\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 10: 38.7% 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 71.6%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg71.6%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define71.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac271.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub071.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified71.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 62.7%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 38.9%

    \[\leadsto \color{blue}{1 + -1 \cdot \frac{x}{y - 1}} \]
  7. Step-by-step derivation
    1. mul-1-neg38.9%

      \[\leadsto 1 + \color{blue}{\left(-\frac{x}{y - 1}\right)} \]
    2. sub-neg38.9%

      \[\leadsto 1 + \left(-\frac{x}{\color{blue}{y + \left(-1\right)}}\right) \]
    3. metadata-eval38.9%

      \[\leadsto 1 + \left(-\frac{x}{y + \color{blue}{-1}}\right) \]
    4. unsub-neg38.9%

      \[\leadsto \color{blue}{1 - \frac{x}{y + -1}} \]
    5. +-commutative38.9%

      \[\leadsto 1 - \frac{x}{\color{blue}{-1 + y}} \]
  8. Simplified38.9%

    \[\leadsto \color{blue}{1 - \frac{x}{-1 + y}} \]
  9. Final simplification38.9%

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

Alternative 11: 37.3% accurate, 37.0× speedup?

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

\\
1 + x
\end{array}
Derivation
  1. Initial program 71.6%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg71.6%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define71.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac271.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub071.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified71.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in y around 0 55.6%

    \[\leadsto \color{blue}{1 - \log \left(1 + -1 \cdot x\right)} \]
  6. Step-by-step derivation
    1. log1p-define55.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-1 \cdot x\right)} \]
    2. mul-1-neg55.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{-x}\right) \]
  7. Simplified55.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(-x\right)} \]
  8. Taylor expanded in x around 0 37.6%

    \[\leadsto \color{blue}{1 + x} \]
  9. Add Preprocessing

Alternative 12: 37.2% 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 71.6%

    \[1 - \log \left(1 - \frac{x - y}{1 - y}\right) \]
  2. Step-by-step derivation
    1. sub-neg71.6%

      \[\leadsto 1 - \log \color{blue}{\left(1 + \left(-\frac{x - y}{1 - y}\right)\right)} \]
    2. log1p-define71.6%

      \[\leadsto 1 - \color{blue}{\mathsf{log1p}\left(-\frac{x - y}{1 - y}\right)} \]
    3. distribute-neg-frac271.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x - y}{-\left(1 - y\right)}}\right) \]
    4. neg-sub071.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{0 - \left(1 - y\right)}}\right) \]
    5. associate--r-71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{\left(0 - 1\right) + y}}\right) \]
    6. metadata-eval71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{-1} + y}\right) \]
    7. +-commutative71.6%

      \[\leadsto 1 - \mathsf{log1p}\left(\frac{x - y}{\color{blue}{y + -1}}\right) \]
  3. Simplified71.6%

    \[\leadsto \color{blue}{1 - \mathsf{log1p}\left(\frac{x - y}{y + -1}\right)} \]
  4. Add Preprocessing
  5. Taylor expanded in x around inf 62.7%

    \[\leadsto 1 - \mathsf{log1p}\left(\color{blue}{\frac{x}{y - 1}}\right) \]
  6. Taylor expanded in x around 0 37.4%

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

Developer Target 1: 88.0% 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 2024170 
(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))))))