Rust f64::asinh

Percentage Accurate: 29.5% → 99.9%
Time: 2.4s
Alternatives: 8
Speedup: 1.8×

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 8 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, 1.6× speedup?

\[\begin{array}{l} \\ \mathsf{copysign}\left(\sinh^{-1} x, x\right) \end{array} \]
(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(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} 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. Applied rewrites99.9%

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

Alternative 2: 82.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -3.2:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\ \mathbf{elif}\;x \leq 1.25:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(2 \cdot x\right), x\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -3.2)
   (copysign (log (fabs x)) x)
   (if (<= x 1.25) (copysign x x) (copysign (log (* 2.0 x)) x))))
double code(double x) {
	double tmp;
	if (x <= -3.2) {
		tmp = copysign(log(fabs(x)), x);
	} else if (x <= 1.25) {
		tmp = copysign(x, x);
	} else {
		tmp = copysign(log((2.0 * x)), x);
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= -3.2) {
		tmp = Math.copySign(Math.log(Math.abs(x)), x);
	} else if (x <= 1.25) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = Math.copySign(Math.log((2.0 * x)), x);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -3.2:
		tmp = math.copysign(math.log(math.fabs(x)), x)
	elif x <= 1.25:
		tmp = math.copysign(x, x)
	else:
		tmp = math.copysign(math.log((2.0 * x)), x)
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -3.2)
		tmp = copysign(log(abs(x)), x);
	elseif (x <= 1.25)
		tmp = copysign(x, x);
	else
		tmp = copysign(log(Float64(2.0 * x)), x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -3.2)
		tmp = sign(x) * abs(log(abs(x)));
	elseif (x <= 1.25)
		tmp = sign(x) * abs(x);
	else
		tmp = sign(x) * abs(log((2.0 * x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -3.2], N[With[{TMP1 = Abs[N[Log[N[Abs[x], $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], 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[(2.0 * x), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -3.2:\\
\;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\

\mathbf{elif}\;x \leq 1.25:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{copysign}\left(\log \left(2 \cdot x\right), x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -3.2000000000000002

    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. Applied rewrites26.9%

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
    4. Taylor expanded in x around 0

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

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right) \]

    if -3.2000000000000002 < 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. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. 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. Applied rewrites18.0%

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

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(2 \cdot x\right)}, x\right) \]
    4. Applied rewrites25.6%

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(2 \cdot x\right)}, x\right) \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 3: 65.6% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -3.2:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\ \mathbf{elif}\;x \leq 1.6:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(1 + x\right), x\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -3.2)
   (copysign (log (fabs x)) x)
   (if (<= x 1.6) (copysign x x) (copysign (log (+ 1.0 x)) x))))
double code(double x) {
	double tmp;
	if (x <= -3.2) {
		tmp = copysign(log(fabs(x)), x);
	} else if (x <= 1.6) {
		tmp = copysign(x, x);
	} else {
		tmp = copysign(log((1.0 + x)), x);
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= -3.2) {
		tmp = Math.copySign(Math.log(Math.abs(x)), x);
	} else if (x <= 1.6) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = Math.copySign(Math.log((1.0 + x)), x);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -3.2:
		tmp = math.copysign(math.log(math.fabs(x)), x)
	elif x <= 1.6:
		tmp = math.copysign(x, x)
	else:
		tmp = math.copysign(math.log((1.0 + x)), x)
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -3.2)
		tmp = copysign(log(abs(x)), x);
	elseif (x <= 1.6)
		tmp = copysign(x, x);
	else
		tmp = copysign(log(Float64(1.0 + x)), x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -3.2)
		tmp = sign(x) * abs(log(abs(x)));
	elseif (x <= 1.6)
		tmp = sign(x) * abs(x);
	else
		tmp = sign(x) * abs(log((1.0 + x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -3.2], N[With[{TMP1 = Abs[N[Log[N[Abs[x], $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], If[LessEqual[x, 1.6], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[N[Log[N[(1.0 + x), $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -3.2:\\
\;\;\;\;\mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\

\mathbf{elif}\;x \leq 1.6:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{copysign}\left(\log \left(1 + x\right), x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -3.2000000000000002

    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. Applied rewrites26.9%

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
    4. Taylor expanded in x around 0

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

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right) \]

    if -3.2000000000000002 < x < 1.6000000000000001

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

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

    if 1.6000000000000001 < x

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites18.0%

      \[\leadsto \mathsf{copysign}\left(\log \left(\color{blue}{x} + \sqrt{x \cdot x + 1}\right), x\right) \]
    3. Taylor expanded in x around 0

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(1 + x\right)}, x\right) \]
    4. Applied rewrites11.5%

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(1 + x\right)}, x\right) \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 4: 65.6% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\ \mathbf{if}\;x \leq -3.2:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;x \leq 3.2:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (copysign (log (fabs x)) x)))
   (if (<= x -3.2) t_0 (if (<= x 3.2) (copysign x x) t_0))))
double code(double x) {
	double t_0 = copysign(log(fabs(x)), x);
	double tmp;
	if (x <= -3.2) {
		tmp = t_0;
	} else if (x <= 3.2) {
		tmp = copysign(x, x);
	} else {
		tmp = t_0;
	}
	return tmp;
}
public static double code(double x) {
	double t_0 = Math.copySign(Math.log(Math.abs(x)), x);
	double tmp;
	if (x <= -3.2) {
		tmp = t_0;
	} else if (x <= 3.2) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x):
	t_0 = math.copysign(math.log(math.fabs(x)), x)
	tmp = 0
	if x <= -3.2:
		tmp = t_0
	elif x <= 3.2:
		tmp = math.copysign(x, x)
	else:
		tmp = t_0
	return tmp
function code(x)
	t_0 = copysign(log(abs(x)), x)
	tmp = 0.0
	if (x <= -3.2)
		tmp = t_0;
	elseif (x <= 3.2)
		tmp = copysign(x, x);
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = sign(x) * abs(log(abs(x)));
	tmp = 0.0;
	if (x <= -3.2)
		tmp = t_0;
	elseif (x <= 3.2)
		tmp = sign(x) * abs(x);
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[With[{TMP1 = Abs[N[Log[N[Abs[x], $MachinePrecision]], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]}, If[LessEqual[x, -3.2], t$95$0, If[LessEqual[x, 3.2], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right)\\
\mathbf{if}\;x \leq -3.2:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;x \leq 3.2:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -3.2000000000000002 or 3.2000000000000002 < 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. Applied rewrites26.9%

      \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x \cdot \left(1 + \frac{\left|x\right|}{x}\right)\right)}, x\right) \]
    4. Taylor expanded in x around 0

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

      \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right|\right), x\right) \]

    if -3.2000000000000002 < x < 3.2000000000000002

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

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

Alternative 5: 57.4% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2:\\ \;\;\;\;\mathsf{copysign}\left(2, x\right)\\ \mathbf{elif}\;x \leq 6:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(2 \cdot 3, 2 \cdot 3\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -2.0)
   (copysign 2.0 x)
   (if (<= x 6.0) (copysign x x) (copysign (* 2.0 3.0) (* 2.0 3.0)))))
double code(double x) {
	double tmp;
	if (x <= -2.0) {
		tmp = copysign(2.0, x);
	} else if (x <= 6.0) {
		tmp = copysign(x, x);
	} else {
		tmp = copysign((2.0 * 3.0), (2.0 * 3.0));
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= -2.0) {
		tmp = Math.copySign(2.0, x);
	} else if (x <= 6.0) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = Math.copySign((2.0 * 3.0), (2.0 * 3.0));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -2.0:
		tmp = math.copysign(2.0, x)
	elif x <= 6.0:
		tmp = math.copysign(x, x)
	else:
		tmp = math.copysign((2.0 * 3.0), (2.0 * 3.0))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -2.0)
		tmp = copysign(2.0, x);
	elseif (x <= 6.0)
		tmp = copysign(x, x);
	else
		tmp = copysign(Float64(2.0 * 3.0), Float64(2.0 * 3.0));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -2.0)
		tmp = sign(x) * abs(2.0);
	elseif (x <= 6.0)
		tmp = sign(x) * abs(x);
	else
		tmp = sign((2.0 * 3.0)) * abs((2.0 * 3.0));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -2.0], N[With[{TMP1 = Abs[2.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], If[LessEqual[x, 6.0], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[N[(2.0 * 3.0), $MachinePrecision]], TMP2 = Sign[N[(2.0 * 3.0), $MachinePrecision]]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -2:\\
\;\;\;\;\mathsf{copysign}\left(2, x\right)\\

\mathbf{elif}\;x \leq 6:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{copysign}\left(2 \cdot 3, 2 \cdot 3\right)\\


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

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

      \[\leadsto \color{blue}{\mathsf{copysign}\left(\sinh^{-1} x, x\right)} \]
    3. Applied rewrites9.9%

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

    if -2 < x < 6

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

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

    if 6 < x

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    5. Applied rewrites10.0%

      \[\leadsto \mathsf{copysign}\left(2 \cdot \color{blue}{2}, x\right) \]
    6. Applied rewrites5.9%

      \[\leadsto \mathsf{copysign}\left(2 \cdot 2, \color{blue}{2 \cdot 2}\right) \]
    7. Applied rewrites6.0%

      \[\leadsto \mathsf{copysign}\left(2 \cdot \color{blue}{3}, 2 \cdot 2\right) \]
    8. Applied rewrites6.0%

      \[\leadsto \mathsf{copysign}\left(2 \cdot 3, \color{blue}{2 \cdot 3}\right) \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 6: 57.4% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2:\\ \;\;\;\;\mathsf{copysign}\left(2, x\right)\\ \mathbf{elif}\;x \leq 4:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(2 \cdot 2, 2 \cdot 2\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -2.0)
   (copysign 2.0 x)
   (if (<= x 4.0) (copysign x x) (copysign (* 2.0 2.0) (* 2.0 2.0)))))
double code(double x) {
	double tmp;
	if (x <= -2.0) {
		tmp = copysign(2.0, x);
	} else if (x <= 4.0) {
		tmp = copysign(x, x);
	} else {
		tmp = copysign((2.0 * 2.0), (2.0 * 2.0));
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= -2.0) {
		tmp = Math.copySign(2.0, x);
	} else if (x <= 4.0) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = Math.copySign((2.0 * 2.0), (2.0 * 2.0));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -2.0:
		tmp = math.copysign(2.0, x)
	elif x <= 4.0:
		tmp = math.copysign(x, x)
	else:
		tmp = math.copysign((2.0 * 2.0), (2.0 * 2.0))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -2.0)
		tmp = copysign(2.0, x);
	elseif (x <= 4.0)
		tmp = copysign(x, x);
	else
		tmp = copysign(Float64(2.0 * 2.0), Float64(2.0 * 2.0));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -2.0)
		tmp = sign(x) * abs(2.0);
	elseif (x <= 4.0)
		tmp = sign(x) * abs(x);
	else
		tmp = sign((2.0 * 2.0)) * abs((2.0 * 2.0));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -2.0], N[With[{TMP1 = Abs[2.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], If[LessEqual[x, 4.0], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[N[(2.0 * 2.0), $MachinePrecision]], TMP2 = Sign[N[(2.0 * 2.0), $MachinePrecision]]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -2:\\
\;\;\;\;\mathsf{copysign}\left(2, x\right)\\

\mathbf{elif}\;x \leq 4:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{copysign}\left(2 \cdot 2, 2 \cdot 2\right)\\


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

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

      \[\leadsto \color{blue}{\mathsf{copysign}\left(\sinh^{-1} x, x\right)} \]
    3. Applied rewrites9.9%

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

    if -2 < x < 4

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

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

    if 4 < x

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    5. Applied rewrites10.0%

      \[\leadsto \mathsf{copysign}\left(2 \cdot \color{blue}{2}, x\right) \]
    6. Applied rewrites5.9%

      \[\leadsto \mathsf{copysign}\left(2 \cdot 2, \color{blue}{2 \cdot 2}\right) \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 7: 57.3% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -2:\\ \;\;\;\;\mathsf{copysign}\left(2, x\right)\\ \mathbf{elif}\;x \leq 2:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(2, x\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -2.0)
   (copysign 2.0 x)
   (if (<= x 2.0) (copysign x x) (copysign 2.0 x))))
double code(double x) {
	double tmp;
	if (x <= -2.0) {
		tmp = copysign(2.0, x);
	} else if (x <= 2.0) {
		tmp = copysign(x, x);
	} else {
		tmp = copysign(2.0, x);
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= -2.0) {
		tmp = Math.copySign(2.0, x);
	} else if (x <= 2.0) {
		tmp = Math.copySign(x, x);
	} else {
		tmp = Math.copySign(2.0, x);
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -2.0:
		tmp = math.copysign(2.0, x)
	elif x <= 2.0:
		tmp = math.copysign(x, x)
	else:
		tmp = math.copysign(2.0, x)
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -2.0)
		tmp = copysign(2.0, x);
	elseif (x <= 2.0)
		tmp = copysign(x, x);
	else
		tmp = copysign(2.0, x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -2.0)
		tmp = sign(x) * abs(2.0);
	elseif (x <= 2.0)
		tmp = sign(x) * abs(x);
	else
		tmp = sign(x) * abs(2.0);
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -2.0], N[With[{TMP1 = Abs[2.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], If[LessEqual[x, 2.0], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[2.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -2:\\
\;\;\;\;\mathsf{copysign}\left(2, x\right)\\

\mathbf{elif}\;x \leq 2:\\
\;\;\;\;\mathsf{copysign}\left(x, x\right)\\

\mathbf{else}:\\
\;\;\;\;\mathsf{copysign}\left(2, x\right)\\


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

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

      \[\leadsto \color{blue}{\mathsf{copysign}\left(\sinh^{-1} x, x\right)} \]
    3. Applied rewrites9.9%

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

    if -2 < x < 2

    1. Initial program 29.5%

      \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
    2. Applied rewrites99.9%

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

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
    4. Applied rewrites52.9%

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

Alternative 8: 9.9% accurate, 5.4× speedup?

\[\begin{array}{l} \\ \mathsf{copysign}\left(2, x\right) \end{array} \]
(FPCore (x) :precision binary64 (copysign 2.0 x))
double code(double x) {
	return copysign(2.0, x);
}
public static double code(double x) {
	return Math.copySign(2.0, x);
}
def code(x):
	return math.copysign(2.0, x)
function code(x)
	return copysign(2.0, x)
end
function tmp = code(x)
	tmp = sign(x) * abs(2.0);
end
code[x_] := N[With[{TMP1 = Abs[2.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{copysign}\left(2, 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. Applied rewrites99.9%

    \[\leadsto \color{blue}{\mathsf{copysign}\left(\sinh^{-1} x, x\right)} \]
  3. Applied rewrites9.9%

    \[\leadsto \mathsf{copysign}\left(\color{blue}{2}, x\right) \]
  4. 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))