Rust f64::asinh

Percentage Accurate: 29.7% → 99.9%
Time: 5.1s
Alternatives: 3
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \sinh^{-1} x \end{array} \]
(FPCore (x) :precision binary64 (asinh x))
double code(double x) {
	return asinh(x);
}
def code(x):
	return math.asinh(x)
function code(x)
	return asinh(x)
end
function tmp = code(x)
	tmp = asinh(x);
end
code[x_] := N[ArcSinh[x], $MachinePrecision]
\begin{array}{l}

\\
\sinh^{-1} x
\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 3 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: 29.7% 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, 1.1× 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 24.2%

    \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
  2. Add Preprocessing
  3. 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.f6499.8

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

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

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{x \cdot x}\right)}, x\right) \]
    13. pow2N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{{x}^{2}}}\right), x\right) \]
    14. sqrt-pow1N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left({x}^{\left(\frac{2}{2}\right)}\right)}, x\right) \]
    15. metadata-evalN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left({x}^{\color{blue}{1}}\right), x\right) \]
    16. unpow199.8

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{x}, x\right) \]
  4. Applied rewrites99.8%

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

Alternative 2: 52.3% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \mathsf{copysign}\left(\mathsf{fma}\left(-0.16666666666666666 \cdot x, x, 1\right) \cdot x, x\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (copysign (* (fma (* -0.16666666666666666 x) x 1.0) x) x))
double code(double x) {
	return copysign((fma((-0.16666666666666666 * x), x, 1.0) * x), x);
}
function code(x)
	return copysign(Float64(fma(Float64(-0.16666666666666666 * x), x, 1.0) * x), x)
end
code[x_] := N[With[{TMP1 = Abs[N[(N[(N[(-0.16666666666666666 * x), $MachinePrecision] * x + 1.0), $MachinePrecision] * x), $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{copysign}\left(\mathsf{fma}\left(-0.16666666666666666 \cdot x, x, 1\right) \cdot x, x\right)
\end{array}
Derivation
  1. Initial program 24.2%

    \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
  2. Add Preprocessing
  3. 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.f6499.8

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

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

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left(\sqrt{x \cdot x}\right)}, x\right) \]
    13. pow2N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left(\sqrt{\color{blue}{{x}^{2}}}\right), x\right) \]
    14. sqrt-pow1N/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{\left({x}^{\left(\frac{2}{2}\right)}\right)}, x\right) \]
    15. metadata-evalN/A

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \left({x}^{\color{blue}{1}}\right), x\right) \]
    16. unpow199.8

      \[\leadsto \mathsf{copysign}\left(\sinh^{-1} \color{blue}{x}, x\right) \]
  4. Applied rewrites99.8%

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

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

      \[\leadsto \mathsf{copysign}\left(x \cdot \color{blue}{\left(\frac{-1}{6} \cdot {x}^{2} + 1\right)}, x\right) \]
    2. distribute-lft-inN/A

      \[\leadsto \mathsf{copysign}\left(\color{blue}{x \cdot \left(\frac{-1}{6} \cdot {x}^{2}\right) + x \cdot 1}, x\right) \]
    3. *-commutativeN/A

      \[\leadsto \mathsf{copysign}\left(x \cdot \color{blue}{\left({x}^{2} \cdot \frac{-1}{6}\right)} + x \cdot 1, x\right) \]
    4. associate-*r*N/A

      \[\leadsto \mathsf{copysign}\left(\color{blue}{\left(x \cdot {x}^{2}\right) \cdot \frac{-1}{6}} + x \cdot 1, x\right) \]
    5. unpow2N/A

      \[\leadsto \mathsf{copysign}\left(\left(x \cdot \color{blue}{\left(x \cdot x\right)}\right) \cdot \frac{-1}{6} + x \cdot 1, x\right) \]
    6. cube-multN/A

      \[\leadsto \mathsf{copysign}\left(\color{blue}{{x}^{3}} \cdot \frac{-1}{6} + x \cdot 1, x\right) \]
    7. *-rgt-identityN/A

      \[\leadsto \mathsf{copysign}\left({x}^{3} \cdot \frac{-1}{6} + \color{blue}{x}, x\right) \]
    8. lower-fma.f64N/A

      \[\leadsto \mathsf{copysign}\left(\color{blue}{\mathsf{fma}\left({x}^{3}, \frac{-1}{6}, x\right)}, x\right) \]
    9. lower-pow.f6458.8

      \[\leadsto \mathsf{copysign}\left(\mathsf{fma}\left(\color{blue}{{x}^{3}}, -0.16666666666666666, x\right), x\right) \]
  7. Applied rewrites58.8%

    \[\leadsto \mathsf{copysign}\left(\color{blue}{\mathsf{fma}\left({x}^{3}, -0.16666666666666666, x\right)}, x\right) \]
  8. Step-by-step derivation
    1. Applied rewrites58.8%

      \[\leadsto \mathsf{copysign}\left(\mathsf{fma}\left(-0.16666666666666666 \cdot \left(x \cdot x\right), \color{blue}{x}, x\right), x\right) \]
    2. Step-by-step derivation
      1. Applied rewrites58.8%

        \[\leadsto \mathsf{copysign}\left(\mathsf{fma}\left(-0.16666666666666666 \cdot x, x, 1\right) \cdot \color{blue}{x}, x\right) \]
      2. Add Preprocessing

      Alternative 3: 12.2% accurate, 2.1× speedup?

      \[\begin{array}{l} \\ \mathsf{copysign}\left(0.5 \cdot x, x\right) \end{array} \]
      (FPCore (x) :precision binary64 (copysign (* 0.5 x) x))
      double code(double x) {
      	return copysign((0.5 * x), x);
      }
      
      public static double code(double x) {
      	return Math.copySign((0.5 * x), x);
      }
      
      def code(x):
      	return math.copysign((0.5 * x), x)
      
      function code(x)
      	return copysign(Float64(0.5 * x), x)
      end
      
      function tmp = code(x)
      	tmp = sign(x) * abs((0.5 * x));
      end
      
      code[x_] := N[With[{TMP1 = Abs[N[(0.5 * x), $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \mathsf{copysign}\left(0.5 \cdot x, x\right)
      \end{array}
      
      Derivation
      1. Initial program 24.2%

        \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\log \left(1 + \left|x\right|\right) + \frac{1}{2} \cdot \frac{{x}^{2}}{1 + \left|x\right|}}, x\right) \]
      4. Step-by-step derivation
        1. *-lft-identityN/A

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

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

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

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

          \[\leadsto \mathsf{copysign}\left(\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} \cdot \frac{1}{1 + \left|x\right|}\right) + \log \left(1 + \left|x\right|\right)}, x\right) \]
        6. unpow2N/A

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

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

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

          \[\leadsto \mathsf{copysign}\left(\color{blue}{\mathsf{fma}\left(x \cdot \left(\frac{1}{2} \cdot \frac{1}{1 + \left|x\right|}\right), x, \log \left(1 + \left|x\right|\right)\right)}, x\right) \]
      5. Applied rewrites59.3%

        \[\leadsto \mathsf{copysign}\left(\color{blue}{\mathsf{fma}\left(\frac{0.5}{1 + \left|x\right|} \cdot x, x, \mathsf{log1p}\left(\left|x\right|\right)\right)}, x\right) \]
      6. Taylor expanded in x around inf

        \[\leadsto \mathsf{copysign}\left(\frac{1}{2} \cdot \color{blue}{\frac{{x}^{2}}{1 + \left|x\right|}}, x\right) \]
      7. Step-by-step derivation
        1. Applied rewrites6.2%

          \[\leadsto \mathsf{copysign}\left(\left(\frac{x}{1 + \left|x\right|} \cdot 0.5\right) \cdot \color{blue}{x}, x\right) \]
        2. Step-by-step derivation
          1. Applied rewrites3.0%

            \[\leadsto \mathsf{copysign}\left(\left(\frac{x}{\mathsf{fma}\left(\sqrt{x}, \sqrt{x}, 1\right)} \cdot 0.5\right) \cdot x, x\right) \]
          2. Taylor expanded in x around -inf

            \[\leadsto \mathsf{copysign}\left(\frac{\frac{-1}{2}}{{\left(\sqrt{-1}\right)}^{2}} \cdot x, x\right) \]
          3. Step-by-step derivation
            1. Applied rewrites13.0%

              \[\leadsto \mathsf{copysign}\left(0.5 \cdot x, x\right) \]
            2. Add Preprocessing

            Developer Target 1: 99.9% accurate, 0.6× 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 2024351 
            (FPCore (x)
              :name "Rust f64::asinh"
              :precision binary64
            
              :alt
              (! :herbie-platform default (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))