Rust f64::asinh

Percentage Accurate: 29.5% → 99.9%
Time: 2.0s
Alternatives: 4
Speedup: 5.4×

Specification

?
\[\begin{array}{l} \\ \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (copysign (log (+ (fabs x) (sqrt (+ (* x x) 1.0)))) x))
double code(double x) {
	return copysign(log((fabs(x) + sqrt(((x * x) + 1.0)))), x);
}
public static double code(double x) {
	return Math.copySign(Math.log((Math.abs(x) + Math.sqrt(((x * x) + 1.0)))), x);
}
def code(x):
	return math.copysign(math.log((math.fabs(x) + math.sqrt(((x * x) + 1.0)))), x)
function code(x)
	return copysign(log(Float64(abs(x) + sqrt(Float64(Float64(x * x) + 1.0)))), x)
end
function tmp = code(x)
	tmp = sign(x) * abs(log((abs(x) + sqrt(((x * x) + 1.0)))));
end
code[x_] := N[With[{TMP1 = Abs[N[Log[N[(N[Abs[x], $MachinePrecision] + N[Sqrt[N[(N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right)
\end{array}

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 4 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: 29.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (copysign (log (+ (fabs x) (sqrt (+ (* x x) 1.0)))) x))
double code(double x) {
	return copysign(log((fabs(x) + sqrt(((x * x) + 1.0)))), x);
}
public static double code(double x) {
	return Math.copySign(Math.log((Math.abs(x) + Math.sqrt(((x * x) + 1.0)))), x);
}
def code(x):
	return math.copysign(math.log((math.fabs(x) + math.sqrt(((x * x) + 1.0)))), x)
function code(x)
	return copysign(log(Float64(abs(x) + sqrt(Float64(Float64(x * x) + 1.0)))), x)
end
function tmp = code(x)
	tmp = sign(x) * abs(log((abs(x) + sqrt(((x * x) + 1.0)))));
end
code[x_] := N[With[{TMP1 = Abs[N[Log[N[(N[Abs[x], $MachinePrecision] + N[Sqrt[N[(N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right)
\end{array}

Alternative 1: 99.9% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \mathsf{copysign}\left(\sinh^{-1} \left(-x\right), x\right) \end{array} \]
(FPCore (x) :precision binary64 (copysign (asinh (- x)) x))
double code(double x) {
	return copysign(asinh(-x), x);
}
def code(x):
	return math.copysign(math.asinh(-x), x)
function code(x)
	return copysign(asinh(Float64(-x)), x)
end
function tmp = code(x)
	tmp = sign(x) * abs(asinh(-x));
end
code[x_] := N[With[{TMP1 = Abs[N[ArcSinh[(-x)], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{copysign}\left(\sinh^{-1} \left(-x\right), x\right)
\end{array}
Derivation
  1. Initial program 29.5%

    \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
  2. Step-by-step derivation
    1. lift-log.f64N/A

      \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
    2. lift-+.f64N/A

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
    3. lift-sqrt.f64N/A

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{\sqrt{x \cdot x + 1}}\right), x\right) \]
    4. lift-+.f64N/A

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x + 1}}\right), x\right) \]
    5. lift-*.f64N/A

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x} + 1}\right), x\right) \]
    6. sqr-abs-revN/A

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right| \cdot \left|x\right|} + 1}\right), x\right) \]
    7. lift-fabs.f64N/A

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right|} \cdot \left|x\right| + 1}\right), x\right) \]
    8. lift-fabs.f64N/A

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\left|x\right| \cdot \color{blue}{\left|x\right|} + 1}\right), x\right) \]
    9. asinh-def-revN/A

      \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
    10. lower-asinh.f6499.9

      \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
  3. Applied rewrites99.9%

    \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
  4. Step-by-step derivation
    1. lift-fabs.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\left|x\right|\right)}, x\right) \]
    2. rem-sqrt-square-revN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{x \cdot x}\right)}, x\right) \]
    3. *-rgt-identityN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 1}}\right), x\right) \]
    4. metadata-evalN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\left(-1 \cdot -1\right)}}\right), x\right) \]
    5. metadata-evalN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{1}}\right), x\right) \]
    6. metadata-evalN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\frac{2}{2}}}\right), x\right) \]
    7. associate-*r/N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\frac{\left(x \cdot x\right) \cdot 2}{2}}}\right), x\right) \]
    8. sqrt-divN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
    9. lower-unsound-/.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
    10. lower-unsound-sqrt.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\color{blue}{\sqrt{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
    11. lower-*.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
    12. lower-*.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right)} \cdot 2}}{\sqrt{2}}\right), x\right) \]
    13. lower-unsound-sqrt.f6453.2

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\color{blue}{\sqrt{2}}}\right), x\right) \]
  5. Applied rewrites53.2%

    \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
  6. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
    2. lift-sqrt.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\color{blue}{\sqrt{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
    3. lift-sqrt.f64N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\color{blue}{\sqrt{2}}}\right), x\right) \]
    4. sqrt-undivN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{\frac{\left(x \cdot x\right) \cdot 2}{2}}\right)}, x\right) \]
    5. pow1/2N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left({\left(\frac{\left(x \cdot x\right) \cdot 2}{2}\right)}^{\frac{1}{2}}\right)}, x\right) \]
    6. sqr-powN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left({\left(\frac{\left(x \cdot x\right) \cdot 2}{2}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot {\left(\frac{\left(x \cdot x\right) \cdot 2}{2}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}\right)}, x\right) \]
  7. Applied rewrites99.9%

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

Alternative 2: 75.7% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 1.25:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right| + x\right), x\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x 1.25) (copysign x x) (copysign (log (+ (fabs x) x)) x)))
double code(double x) {
	double tmp;
	if (x <= 1.25) {
		tmp = copysign(x, x);
	} else {
		tmp = copysign(log((fabs(x) + x)), x);
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= 1.25) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = Math.copySign(Math.log((Math.abs(x) + x)), x);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= 1.25:
		tmp = math.copysign(x, x)
	else:
		tmp = math.copysign(math.log((math.fabs(x) + x)), x)
	return tmp
function code(x)
	tmp = 0.0
	if (x <= 1.25)
		tmp = copysign(x, x);
	else
		tmp = copysign(log(Float64(abs(x) + x)), x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= 1.25)
		tmp = sign(x) * abs(x);
	else
		tmp = sign(x) * abs(log((abs(x) + x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, 1.25], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[N[Log[N[(N[Abs[x], $MachinePrecision] + x), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 1.25:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right| + x\right), x\right)\\


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

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Step-by-step derivation
      1. lift-log.f64N/A

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
      2. lift-+.f64N/A

        \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{\sqrt{x \cdot x + 1}}\right), x\right) \]
      4. lift-+.f64N/A

        \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x + 1}}\right), x\right) \]
      5. lift-*.f64N/A

        \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x} + 1}\right), x\right) \]
      6. sqr-abs-revN/A

        \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right| \cdot \left|x\right|} + 1}\right), x\right) \]
      7. lift-fabs.f64N/A

        \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right|} \cdot \left|x\right| + 1}\right), x\right) \]
      8. lift-fabs.f64N/A

        \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\left|x\right| \cdot \color{blue}{\left|x\right|} + 1}\right), x\right) \]
      9. asinh-def-revN/A

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
      10. lower-asinh.f6499.9

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
    3. Applied rewrites99.9%

      \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
    4. Step-by-step derivation
      1. lift-fabs.f64N/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\left|x\right|\right)}, x\right) \]
      2. rem-sqrt-square-revN/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{x \cdot x}\right)}, x\right) \]
      3. *-rgt-identityN/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 1}}\right), x\right) \]
      4. metadata-evalN/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\left(-1 \cdot -1\right)}}\right), x\right) \]
      5. metadata-evalN/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{1}}\right), x\right) \]
      6. metadata-evalN/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\frac{2}{2}}}\right), x\right) \]
      7. associate-*r/N/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\frac{\left(x \cdot x\right) \cdot 2}{2}}}\right), x\right) \]
      8. sqrt-divN/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
      9. lower-unsound-/.f64N/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
      10. lower-unsound-sqrt.f64N/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\color{blue}{\sqrt{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
      11. lower-*.f64N/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
      12. lower-*.f64N/A

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right)} \cdot 2}}{\sqrt{2}}\right), x\right) \]
      13. lower-unsound-sqrt.f6453.2

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\color{blue}{\sqrt{2}}}\right), x\right) \]
    5. Applied rewrites53.2%

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
    6. Taylor expanded in x around 0

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    7. Step-by-step derivation
      1. Applied rewrites52.9%

        \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]

      if 1.25 < x

      1. Initial program 29.5%

        \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
      2. Taylor expanded in x around inf

        \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
      3. Step-by-step derivation
        1. lower-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \color{blue}{\left(1 + \frac{\left|x\right|}{x}\right)}\right), x\right) \]
        2. lower-+.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \left(1 + \color{blue}{\frac{\left|x\right|}{x}}\right)\right), x\right) \]
        3. lower-/.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \left(1 + \frac{\left|x\right|}{\color{blue}{x}}\right)\right), x\right) \]
        4. lower-fabs.f6426.9

          \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right), x\right) \]
      4. Applied rewrites26.9%

        \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
      5. Step-by-step derivation
        1. lift-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \color{blue}{\left(1 + \frac{\left|x\right|}{x}\right)}\right), x\right) \]
        2. *-commutativeN/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left(1 + \frac{\left|x\right|}{x}\right) \cdot \color{blue}{x}\right), x\right) \]
        3. lift-+.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left(1 + \frac{\left|x\right|}{x}\right) \cdot x\right), x\right) \]
        4. lift-/.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left(1 + \frac{\left|x\right|}{x}\right) \cdot x\right), x\right) \]
        5. sum-to-mult-revN/A

          \[\leadsto \mathsf{copysign}\left(\log \left(x + \color{blue}{\left|x\right|}\right), x\right) \]
        6. +-commutativeN/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{x}\right), x\right) \]
        7. lower-+.f6426.9

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{x}\right), x\right) \]
      6. Applied rewrites26.9%

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(\left|x\right| + x\right)}, x\right) \]
    8. Recombined 2 regimes into one program.
    9. Add Preprocessing

    Alternative 3: 59.2% accurate, 0.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \leq 0.05:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\ \end{array} \end{array} \]
    (FPCore (x)
     :precision binary64
     (if (<= (copysign (log (+ (fabs x) (sqrt (+ (* x x) 1.0)))) x) 0.05)
       (copysign x x)
       (copysign (log (fabs x)) x)))
    double code(double x) {
    	double tmp;
    	if (copysign(log((fabs(x) + sqrt(((x * x) + 1.0)))), x) <= 0.05) {
    		tmp = copysign(x, x);
    	} else {
    		tmp = copysign(log(fabs(x)), x);
    	}
    	return tmp;
    }
    
    public static double code(double x) {
    	double tmp;
    	if (Math.copySign(Math.log((Math.abs(x) + Math.sqrt(((x * x) + 1.0)))), x) <= 0.05) {
    		tmp = Math.copySign(x, x);
    	} else {
    		tmp = Math.copySign(Math.log(Math.abs(x)), x);
    	}
    	return tmp;
    }
    
    def code(x):
    	tmp = 0
    	if math.copysign(math.log((math.fabs(x) + math.sqrt(((x * x) + 1.0)))), x) <= 0.05:
    		tmp = math.copysign(x, x)
    	else:
    		tmp = math.copysign(math.log(math.fabs(x)), x)
    	return tmp
    
    function code(x)
    	tmp = 0.0
    	if (copysign(log(Float64(abs(x) + sqrt(Float64(Float64(x * x) + 1.0)))), x) <= 0.05)
    		tmp = copysign(x, x);
    	else
    		tmp = copysign(log(abs(x)), x);
    	end
    	return tmp
    end
    
    function tmp_2 = code(x)
    	tmp = 0.0;
    	if ((sign(x) * abs(log((abs(x) + sqrt(((x * x) + 1.0)))))) <= 0.05)
    		tmp = sign(x) * abs(x);
    	else
    		tmp = sign(x) * abs(log(abs(x)));
    	end
    	tmp_2 = tmp;
    end
    
    code[x_] := If[LessEqual[N[With[{TMP1 = Abs[N[Log[N[(N[Abs[x], $MachinePrecision] + N[Sqrt[N[(N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], 0.05], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[N[Log[N[Abs[x], $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \leq 0.05:\\
    \;\;\;\;\mathsf{copysign}\left(x, x\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (copysign.f64 (log.f64 (+.f64 (fabs.f64 x) (sqrt.f64 (+.f64 (*.f64 x x) #s(literal 1 binary64))))) x) < 0.050000000000000003

      1. Initial program 29.5%

        \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
      2. Step-by-step derivation
        1. lift-log.f64N/A

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
        2. lift-+.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
        3. lift-sqrt.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{\sqrt{x \cdot x + 1}}\right), x\right) \]
        4. lift-+.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x + 1}}\right), x\right) \]
        5. lift-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x} + 1}\right), x\right) \]
        6. sqr-abs-revN/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right| \cdot \left|x\right|} + 1}\right), x\right) \]
        7. lift-fabs.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right|} \cdot \left|x\right| + 1}\right), x\right) \]
        8. lift-fabs.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\left|x\right| \cdot \color{blue}{\left|x\right|} + 1}\right), x\right) \]
        9. asinh-def-revN/A

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
        10. lower-asinh.f6499.9

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
      3. Applied rewrites99.9%

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
      4. Step-by-step derivation
        1. lift-fabs.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\left|x\right|\right)}, x\right) \]
        2. rem-sqrt-square-revN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{x \cdot x}\right)}, x\right) \]
        3. *-rgt-identityN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 1}}\right), x\right) \]
        4. metadata-evalN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\left(-1 \cdot -1\right)}}\right), x\right) \]
        5. metadata-evalN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{1}}\right), x\right) \]
        6. metadata-evalN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\frac{2}{2}}}\right), x\right) \]
        7. associate-*r/N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\frac{\left(x \cdot x\right) \cdot 2}{2}}}\right), x\right) \]
        8. sqrt-divN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
        9. lower-unsound-/.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
        10. lower-unsound-sqrt.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\color{blue}{\sqrt{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
        11. lower-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
        12. lower-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right)} \cdot 2}}{\sqrt{2}}\right), x\right) \]
        13. lower-unsound-sqrt.f6453.2

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\color{blue}{\sqrt{2}}}\right), x\right) \]
      5. Applied rewrites53.2%

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
      6. Taylor expanded in x around 0

        \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
      7. Step-by-step derivation
        1. Applied rewrites52.9%

          \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]

        if 0.050000000000000003 < (copysign.f64 (log.f64 (+.f64 (fabs.f64 x) (sqrt.f64 (+.f64 (*.f64 x x) #s(literal 1 binary64))))) x)

        1. Initial program 29.5%

          \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
        2. Taylor expanded in x around inf

          \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
        3. Step-by-step derivation
          1. lower-*.f64N/A

            \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \color{blue}{\left(1 + \frac{\left|x\right|}{x}\right)}\right), x\right) \]
          2. lower-+.f64N/A

            \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \left(1 + \color{blue}{\frac{\left|x\right|}{x}}\right)\right), x\right) \]
          3. lower-/.f64N/A

            \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \left(1 + \frac{\left|x\right|}{\color{blue}{x}}\right)\right), x\right) \]
          4. lower-fabs.f6426.9

            \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right), x\right) \]
        4. Applied rewrites26.9%

          \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
        5. Step-by-step derivation
          1. lift-*.f64N/A

            \[\leadsto \mathsf{copysign}\left(\log \left(x \cdot \color{blue}{\left(1 + \frac{\left|x\right|}{x}\right)}\right), x\right) \]
          2. *-commutativeN/A

            \[\leadsto \mathsf{copysign}\left(\log \left(\left(1 + \frac{\left|x\right|}{x}\right) \cdot \color{blue}{x}\right), x\right) \]
          3. lift-+.f64N/A

            \[\leadsto \mathsf{copysign}\left(\log \left(\left(1 + \frac{\left|x\right|}{x}\right) \cdot x\right), x\right) \]
          4. lift-/.f64N/A

            \[\leadsto \mathsf{copysign}\left(\log \left(\left(1 + \frac{\left|x\right|}{x}\right) \cdot x\right), x\right) \]
          5. sum-to-mult-revN/A

            \[\leadsto \mathsf{copysign}\left(\log \left(x + \color{blue}{\left|x\right|}\right), x\right) \]
          6. +-commutativeN/A

            \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{x}\right), x\right) \]
          7. lower-+.f6426.9

            \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{x}\right), x\right) \]
        6. Applied rewrites26.9%

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(\left|x\right| + x\right)}, x\right) \]
        7. Taylor expanded in x around 0

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right) \]
        8. Step-by-step derivation
          1. lower-fabs.f6418.2

            \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right) \]
        9. Applied rewrites18.2%

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right) \]
      8. Recombined 2 regimes into one program.
      9. Add Preprocessing

      Alternative 4: 52.9% accurate, 5.4× speedup?

      \[\begin{array}{l} \\ \mathsf{copysign}\left(x, x\right) \end{array} \]
      (FPCore (x) :precision binary64 (copysign x x))
      double code(double x) {
      	return copysign(x, x);
      }
      
      public static double code(double x) {
      	return Math.copySign(x, x);
      }
      
      def code(x):
      	return math.copysign(x, x)
      
      function code(x)
      	return copysign(x, x)
      end
      
      function tmp = code(x)
      	tmp = sign(x) * abs(x);
      end
      
      code[x_] := N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \mathsf{copysign}\left(x, x\right)
      \end{array}
      
      Derivation
      1. Initial program 29.5%

        \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
      2. Step-by-step derivation
        1. lift-log.f64N/A

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
        2. lift-+.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(\left|x\right| + \sqrt{x \cdot x + 1}\right)}, x\right) \]
        3. lift-sqrt.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{\sqrt{x \cdot x + 1}}\right), x\right) \]
        4. lift-+.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x + 1}}\right), x\right) \]
        5. lift-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{x \cdot x} + 1}\right), x\right) \]
        6. sqr-abs-revN/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right| \cdot \left|x\right|} + 1}\right), x\right) \]
        7. lift-fabs.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\color{blue}{\left|x\right|} \cdot \left|x\right| + 1}\right), x\right) \]
        8. lift-fabs.f64N/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{\left|x\right| \cdot \color{blue}{\left|x\right|} + 1}\right), x\right) \]
        9. asinh-def-revN/A

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
        10. lower-asinh.f6499.9

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
      3. Applied rewrites99.9%

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\sinh^{-1} \left(\left|x\right|\right)}, x\right) \]
      4. Step-by-step derivation
        1. lift-fabs.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\left|x\right|\right)}, x\right) \]
        2. rem-sqrt-square-revN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{x \cdot x}\right)}, x\right) \]
        3. *-rgt-identityN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 1}}\right), x\right) \]
        4. metadata-evalN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\left(-1 \cdot -1\right)}}\right), x\right) \]
        5. metadata-evalN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{1}}\right), x\right) \]
        6. metadata-evalN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\left(x \cdot x\right) \cdot \color{blue}{\frac{2}{2}}}\right), x\right) \]
        7. associate-*r/N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{\frac{\left(x \cdot x\right) \cdot 2}{2}}}\right), x\right) \]
        8. sqrt-divN/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
        9. lower-unsound-/.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
        10. lower-unsound-sqrt.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\color{blue}{\sqrt{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
        11. lower-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right) \cdot 2}}}{\sqrt{2}}\right), x\right) \]
        12. lower-*.f64N/A

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\color{blue}{\left(x \cdot x\right)} \cdot 2}}{\sqrt{2}}\right), x\right) \]
        13. lower-unsound-sqrt.f6453.2

          \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\color{blue}{\sqrt{2}}}\right), x\right) \]
      5. Applied rewrites53.2%

        \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\frac{\sqrt{\left(x \cdot x\right) \cdot 2}}{\sqrt{2}}\right)}, x\right) \]
      6. Taylor expanded in x around 0

        \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
      7. Step-by-step derivation
        1. Applied rewrites52.9%

          \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
        2. Add Preprocessing

        Developer Target 1: 99.9% accurate, 0.4× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{\left|x\right|}\\ \mathsf{copysign}\left(\mathsf{log1p}\left(\left|x\right| + \frac{\left|x\right|}{\mathsf{hypot}\left(1, t\_0\right) + t\_0}\right), x\right) \end{array} \end{array} \]
        (FPCore (x)
         :precision binary64
         (let* ((t_0 (/ 1.0 (fabs x))))
           (copysign (log1p (+ (fabs x) (/ (fabs x) (+ (hypot 1.0 t_0) t_0)))) x)))
        double code(double x) {
        	double t_0 = 1.0 / fabs(x);
        	return copysign(log1p((fabs(x) + (fabs(x) / (hypot(1.0, t_0) + t_0)))), x);
        }
        
        public static double code(double x) {
        	double t_0 = 1.0 / Math.abs(x);
        	return Math.copySign(Math.log1p((Math.abs(x) + (Math.abs(x) / (Math.hypot(1.0, t_0) + t_0)))), x);
        }
        
        def code(x):
        	t_0 = 1.0 / math.fabs(x)
        	return math.copysign(math.log1p((math.fabs(x) + (math.fabs(x) / (math.hypot(1.0, t_0) + t_0)))), x)
        
        function code(x)
        	t_0 = Float64(1.0 / abs(x))
        	return copysign(log1p(Float64(abs(x) + Float64(abs(x) / Float64(hypot(1.0, t_0) + t_0)))), x)
        end
        
        code[x_] := Block[{t$95$0 = N[(1.0 / N[Abs[x], $MachinePrecision]), $MachinePrecision]}, N[With[{TMP1 = Abs[N[Log[1 + N[(N[Abs[x], $MachinePrecision] + N[(N[Abs[x], $MachinePrecision] / N[(N[Sqrt[1.0 ^ 2 + t$95$0 ^ 2], $MachinePrecision] + t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_0 := \frac{1}{\left|x\right|}\\
        \mathsf{copysign}\left(\mathsf{log1p}\left(\left|x\right| + \frac{\left|x\right|}{\mathsf{hypot}\left(1, t\_0\right) + t\_0}\right), x\right)
        \end{array}
        \end{array}
        

        Reproduce

        ?
        herbie shell --seed 2025159 
        (FPCore (x)
          :name "Rust f64::asinh"
          :precision binary64
        
          :alt
          (! :herbie-platform c (let* ((ax (fabs x)) (ix (/ 1 ax))) (copysign (log1p (+ ax (/ ax (+ (hypot 1 ix) ix)))) x)))
        
          (copysign (log (+ (fabs x) (sqrt (+ (* x x) 1.0)))) x))