Rust f64::asinh

Percentage Accurate: 29.7% → 99.8%
Time: 2.3s
Alternatives: 6
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 6 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: 99.8% 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 29.7%

    \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
  2. Step-by-step derivation
    1. Applied rewrites99.8%

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

    Alternative 2: 81.9% accurate, 1.1× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -3.2:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(-x\right), x\right)\\ \mathbf{elif}\;x \leq 1.25:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(x + x\right), x\right)\\ \end{array} \end{array} \]
    (FPCore (x)
     :precision binary64
     (if (<= x -3.2)
       (copysign (log (- x)) x)
       (if (<= x 1.25) (copysign x x) (copysign (log (+ x x)) x))))
    double code(double x) {
    	double tmp;
    	if (x <= -3.2) {
    		tmp = copysign(log(-x), x);
    	} else if (x <= 1.25) {
    		tmp = copysign(x, x);
    	} else {
    		tmp = copysign(log((x + x)), x);
    	}
    	return tmp;
    }
    
    public static double code(double x) {
    	double tmp;
    	if (x <= -3.2) {
    		tmp = Math.copySign(Math.log(-x), x);
    	} else if (x <= 1.25) {
    		tmp = Math.copySign(x, x);
    	} else {
    		tmp = Math.copySign(Math.log((x + x)), x);
    	}
    	return tmp;
    }
    
    def code(x):
    	tmp = 0
    	if x <= -3.2:
    		tmp = math.copysign(math.log(-x), x)
    	elif x <= 1.25:
    		tmp = math.copysign(x, x)
    	else:
    		tmp = math.copysign(math.log((x + x)), x)
    	return tmp
    
    function code(x)
    	tmp = 0.0
    	if (x <= -3.2)
    		tmp = copysign(log(Float64(-x)), x);
    	elseif (x <= 1.25)
    		tmp = copysign(x, x);
    	else
    		tmp = copysign(log(Float64(x + x)), x);
    	end
    	return tmp
    end
    
    function tmp_2 = code(x)
    	tmp = 0.0;
    	if (x <= -3.2)
    		tmp = sign(x) * abs(log(-x));
    	elseif (x <= 1.25)
    		tmp = sign(x) * abs(x);
    	else
    		tmp = sign(x) * abs(log((x + x)));
    	end
    	tmp_2 = tmp;
    end
    
    code[x_] := If[LessEqual[x, -3.2], N[With[{TMP1 = Abs[N[Log[(-x)], $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[(x + 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(-x\right), x\right)\\
    
    \mathbf{elif}\;x \leq 1.25:\\
    \;\;\;\;\mathsf{copysign}\left(x, x\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\mathsf{copysign}\left(\log \left(x + x\right), x\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 3 regimes
    2. if x < -3.2000000000000002

      1. Initial program 51.3%

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

        \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(-1 \cdot x\right)}, x\right) \]
      3. Step-by-step derivation
        1. mul-1-negN/A

          \[\leadsto \mathsf{copysign}\left(\log \left(\mathsf{neg}\left(x\right)\right), x\right) \]
        2. lower-neg.f6431.4

          \[\leadsto \mathsf{copysign}\left(\log \left(-x\right), x\right) \]
      4. Applied rewrites31.4%

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

      if -3.2000000000000002 < x < 1.25

      1. Initial program 8.6%

        \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
      2. Step-by-step derivation
        1. Applied rewrites100.0%

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

          \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
        3. Step-by-step derivation
          1. unpow198.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          2. metadata-eval98.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          3. sqrt-pow198.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          4. pow298.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          5. rem-sqrt-square-rev98.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          6. asinh-def-rev98.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          7. sqr-abs-rev98.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          8. pow298.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          9. +-commutative98.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          10. +-commutative98.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
          11. pow298.8

            \[\leadsto \mathsf{copysign}\left(x, x\right) \]
        4. Applied rewrites98.8%

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

        if 1.25 < x

        1. Initial program 50.0%

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

          \[\leadsto \mathsf{copysign}\left(\log \left(\left|x\right| + \color{blue}{x}\right), x\right) \]
        3. Step-by-step derivation
          1. Applied rewrites99.0%

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

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

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

              \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x + \left|x\right|\right)}, x\right) \]
            4. rem-sqrt-square-revN/A

              \[\leadsto \mathsf{copysign}\left(\log \left(x + \color{blue}{\sqrt{x \cdot x}}\right), x\right) \]
            5. pow2N/A

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

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

              \[\leadsto \mathsf{copysign}\left(\log \left(x + {x}^{\color{blue}{1}}\right), x\right) \]
            8. unpow1N/A

              \[\leadsto \mathsf{copysign}\left(\log \left(x + \color{blue}{x}\right), x\right) \]
            9. lower-+.f6499.0

              \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(x + x\right)}, x\right) \]
          3. Applied rewrites99.0%

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

        Alternative 3: 65.0% accurate, 1.2× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -3.2:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(-x\right), x\right)\\ \mathbf{elif}\;x \leq 3.2:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log x, x\right)\\ \end{array} \end{array} \]
        (FPCore (x)
         :precision binary64
         (if (<= x -3.2)
           (copysign (log (- x)) x)
           (if (<= x 3.2) (copysign x x) (copysign (log x) x))))
        double code(double x) {
        	double tmp;
        	if (x <= -3.2) {
        		tmp = copysign(log(-x), x);
        	} else if (x <= 3.2) {
        		tmp = copysign(x, x);
        	} else {
        		tmp = copysign(log(x), x);
        	}
        	return tmp;
        }
        
        public static double code(double x) {
        	double tmp;
        	if (x <= -3.2) {
        		tmp = Math.copySign(Math.log(-x), x);
        	} else if (x <= 3.2) {
        		tmp = Math.copySign(x, x);
        	} else {
        		tmp = Math.copySign(Math.log(x), x);
        	}
        	return tmp;
        }
        
        def code(x):
        	tmp = 0
        	if x <= -3.2:
        		tmp = math.copysign(math.log(-x), x)
        	elif x <= 3.2:
        		tmp = math.copysign(x, x)
        	else:
        		tmp = math.copysign(math.log(x), x)
        	return tmp
        
        function code(x)
        	tmp = 0.0
        	if (x <= -3.2)
        		tmp = copysign(log(Float64(-x)), x);
        	elseif (x <= 3.2)
        		tmp = copysign(x, x);
        	else
        		tmp = copysign(log(x), x);
        	end
        	return tmp
        end
        
        function tmp_2 = code(x)
        	tmp = 0.0;
        	if (x <= -3.2)
        		tmp = sign(x) * abs(log(-x));
        	elseif (x <= 3.2)
        		tmp = sign(x) * abs(x);
        	else
        		tmp = sign(x) * abs(log(x));
        	end
        	tmp_2 = tmp;
        end
        
        code[x_] := If[LessEqual[x, -3.2], N[With[{TMP1 = Abs[N[Log[(-x)], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], If[LessEqual[x, 3.2], N[With[{TMP1 = Abs[x], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], N[With[{TMP1 = Abs[N[Log[x], $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(-x\right), x\right)\\
        
        \mathbf{elif}\;x \leq 3.2:\\
        \;\;\;\;\mathsf{copysign}\left(x, x\right)\\
        
        \mathbf{else}:\\
        \;\;\;\;\mathsf{copysign}\left(\log x, x\right)\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 3 regimes
        2. if x < -3.2000000000000002

          1. Initial program 51.3%

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

            \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(-1 \cdot x\right)}, x\right) \]
          3. Step-by-step derivation
            1. mul-1-negN/A

              \[\leadsto \mathsf{copysign}\left(\log \left(\mathsf{neg}\left(x\right)\right), x\right) \]
            2. lower-neg.f6431.4

              \[\leadsto \mathsf{copysign}\left(\log \left(-x\right), x\right) \]
          4. Applied rewrites31.4%

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

          if -3.2000000000000002 < x < 3.2000000000000002

          1. Initial program 8.7%

            \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
          2. Step-by-step derivation
            1. Applied rewrites100.0%

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

              \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
            3. Step-by-step derivation
              1. unpow198.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              2. metadata-eval98.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              3. sqrt-pow198.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              4. pow298.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              5. rem-sqrt-square-rev98.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              6. asinh-def-rev98.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              7. sqr-abs-rev98.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              8. pow298.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              9. +-commutative98.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              10. +-commutative98.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
              11. pow298.7

                \[\leadsto \mathsf{copysign}\left(x, x\right) \]
            4. Applied rewrites98.7%

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

            if 3.2000000000000002 < x

            1. Initial program 50.0%

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

              \[\leadsto \mathsf{copysign}\left(\log \color{blue}{x}, x\right) \]
            3. Step-by-step derivation
              1. Applied rewrites31.5%

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

            Alternative 4: 65.0% accurate, 1.1× speedup?

            \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -3.2:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(-x\right), x\right)\\ \mathbf{elif}\;x \leq 1.55:\\ \;\;\;\;\mathsf{copysign}\left(x, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{copysign}\left(\log \left(1 + x\right), x\right)\\ \end{array} \end{array} \]
            (FPCore (x)
             :precision binary64
             (if (<= x -3.2)
               (copysign (log (- x)) x)
               (if (<= x 1.55) (copysign x x) (copysign (log (+ 1.0 x)) x))))
            double code(double x) {
            	double tmp;
            	if (x <= -3.2) {
            		tmp = copysign(log(-x), x);
            	} else if (x <= 1.55) {
            		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(-x), x);
            	} else if (x <= 1.55) {
            		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(-x), x)
            	elif x <= 1.55:
            		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(Float64(-x)), x);
            	elseif (x <= 1.55)
            		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(-x));
            	elseif (x <= 1.55)
            		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[(-x)], $MachinePrecision]], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], If[LessEqual[x, 1.55], 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(-x\right), x\right)\\
            
            \mathbf{elif}\;x \leq 1.55:\\
            \;\;\;\;\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 51.3%

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

                \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(-1 \cdot x\right)}, x\right) \]
              3. Step-by-step derivation
                1. mul-1-negN/A

                  \[\leadsto \mathsf{copysign}\left(\log \left(\mathsf{neg}\left(x\right)\right), x\right) \]
                2. lower-neg.f6431.4

                  \[\leadsto \mathsf{copysign}\left(\log \left(-x\right), x\right) \]
              4. Applied rewrites31.4%

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

              if -3.2000000000000002 < x < 1.55000000000000004

              1. Initial program 8.6%

                \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
              2. Step-by-step derivation
                1. Applied rewrites100.0%

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

                  \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
                3. Step-by-step derivation
                  1. unpow198.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  2. metadata-eval98.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  3. sqrt-pow198.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  4. pow298.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  5. rem-sqrt-square-rev98.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  6. asinh-def-rev98.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  7. sqr-abs-rev98.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  8. pow298.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  9. +-commutative98.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  10. +-commutative98.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  11. pow298.8

                    \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                4. Applied rewrites98.8%

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

                if 1.55000000000000004 < x

                1. Initial program 50.0%

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

                  \[\leadsto \mathsf{copysign}\left(\log \color{blue}{\left(1 + \left|x\right|\right)}, x\right) \]
                3. Step-by-step derivation
                  1. rem-sqrt-square-revN/A

                    \[\leadsto \mathsf{copysign}\left(\log \left(1 + \sqrt{x \cdot x}\right), x\right) \]
                  2. pow2N/A

                    \[\leadsto \mathsf{copysign}\left(\log \left(1 + \sqrt{{x}^{2}}\right), x\right) \]
                  3. sqrt-pow1N/A

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

                    \[\leadsto \mathsf{copysign}\left(\log \left(1 + {x}^{1}\right), x\right) \]
                  5. unpow1N/A

                    \[\leadsto \mathsf{copysign}\left(\log \left(1 + x\right), x\right) \]
                  6. lower-+.f6431.4

                    \[\leadsto \mathsf{copysign}\left(\log \left(1 + \color{blue}{x}\right), x\right) \]
                4. Applied rewrites31.4%

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

              Alternative 5: 58.4% accurate, 0.6× speedup?

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

                1. Initial program 23.0%

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

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

                    \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
                  3. Step-by-step derivation
                    1. unpow167.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    2. metadata-eval67.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    3. sqrt-pow167.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    4. pow267.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    5. rem-sqrt-square-rev67.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    6. asinh-def-rev67.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    7. sqr-abs-rev67.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    8. pow267.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    9. +-commutative67.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    10. +-commutative67.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    11. pow267.5

                      \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                  4. Applied rewrites67.5%

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

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

                  1. Initial program 50.0%

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

                    \[\leadsto \mathsf{copysign}\left(\log \color{blue}{x}, x\right) \]
                  3. Step-by-step derivation
                    1. Applied rewrites31.4%

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

                  Alternative 6: 51.9% 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 29.7%

                    \[\mathsf{copysign}\left(\log \left(\left|x\right| + \sqrt{x \cdot x + 1}\right), x\right) \]
                  2. Step-by-step derivation
                    1. Applied rewrites99.8%

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

                      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
                    3. Step-by-step derivation
                      1. unpow151.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      2. metadata-eval51.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      3. sqrt-pow151.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      4. pow251.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      5. rem-sqrt-square-rev51.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      6. asinh-def-rev51.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      7. sqr-abs-rev51.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      8. pow251.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      9. +-commutative51.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      10. +-commutative51.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                      11. pow251.9

                        \[\leadsto \mathsf{copysign}\left(x, x\right) \]
                    4. Applied rewrites51.9%

                      \[\leadsto \mathsf{copysign}\left(\color{blue}{x}, x\right) \]
                    5. 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 2025106 
                    (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))