Hyperbolic arcsine

Percentage Accurate: 18.1% → 99.9%
Time: 9.4s
Alternatives: 9
Speedup: 207.0×

Specification

?
\[\begin{array}{l} \\ \log \left(x + \sqrt{x \cdot x + 1}\right) \end{array} \]
(FPCore (x) :precision binary64 (log (+ x (sqrt (+ (* x x) 1.0)))))
double code(double x) {
	return log((x + sqrt(((x * x) + 1.0))));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log((x + sqrt(((x * x) + 1.0d0))))
end function
public static double code(double x) {
	return Math.log((x + Math.sqrt(((x * x) + 1.0))));
}
def code(x):
	return math.log((x + math.sqrt(((x * x) + 1.0))))
function code(x)
	return log(Float64(x + sqrt(Float64(Float64(x * x) + 1.0))))
end
function tmp = code(x)
	tmp = log((x + sqrt(((x * x) + 1.0))));
end
code[x_] := N[Log[N[(x + N[Sqrt[N[(N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(x + \sqrt{x \cdot x + 1}\right)
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 9 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: 18.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \log \left(x + \sqrt{x \cdot x + 1}\right) \end{array} \]
(FPCore (x) :precision binary64 (log (+ x (sqrt (+ (* x x) 1.0)))))
double code(double x) {
	return log((x + sqrt(((x * x) + 1.0))));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log((x + sqrt(((x * x) + 1.0d0))))
end function
public static double code(double x) {
	return Math.log((x + Math.sqrt(((x * x) + 1.0))));
}
def code(x):
	return math.log((x + math.sqrt(((x * x) + 1.0))))
function code(x)
	return log(Float64(x + sqrt(Float64(Float64(x * x) + 1.0))))
end
function tmp = code(x)
	tmp = log((x + sqrt(((x * x) + 1.0))));
end
code[x_] := N[Log[N[(x + N[Sqrt[N[(N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(x + \sqrt{x \cdot x + 1}\right)
\end{array}

Alternative 1: 99.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.1:\\ \;\;\;\;\log \left(\frac{1}{x} \cdot \left(-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}\right)\right)\\ \mathbf{elif}\;x \leq 0.023:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + \mathsf{hypot}\left(1, x\right)\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.1)
   (log (* (/ 1.0 x) (+ -0.5 (/ (+ 0.125 (/ -0.0625 (* x x))) (* x x)))))
   (if (<= x 0.023)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ x (hypot 1.0 x))))))
double code(double x) {
	double tmp;
	if (x <= -1.1) {
		tmp = log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))));
	} else if (x <= 0.023) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log((x + hypot(1.0, x)));
	}
	return tmp;
}
public static double code(double x) {
	double tmp;
	if (x <= -1.1) {
		tmp = Math.log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))));
	} else if (x <= 0.023) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log((x + Math.hypot(1.0, x)));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.1:
		tmp = math.log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))))
	elif x <= 0.023:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log((x + math.hypot(1.0, x)))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.1)
		tmp = log(Float64(Float64(1.0 / x) * Float64(-0.5 + Float64(Float64(0.125 + Float64(-0.0625 / Float64(x * x))) / Float64(x * x)))));
	elseif (x <= 0.023)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(x + hypot(1.0, x)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.1)
		tmp = log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))));
	elseif (x <= 0.023)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log((x + hypot(1.0, x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.1], N[Log[N[(N[(1.0 / x), $MachinePrecision] * N[(-0.5 + N[(N[(0.125 + N[(-0.0625 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 0.023], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(x + N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.1:\\
\;\;\;\;\log \left(\frac{1}{x} \cdot \left(-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}\right)\right)\\

\mathbf{elif}\;x \leq 0.023:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.1000000000000001

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(-1 \cdot \frac{\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      2. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \left(\frac{0.125}{x \cdot x} + \frac{-0.0625}{x \cdot \left(x \cdot \left(x \cdot x\right)\right)}\right)}{x}\right)} \]
    6. Taylor expanded in x around inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)}{x}\right)}\right) \]
    7. Step-by-step derivation
      1. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right)\right)}{x}\right)\right) \]
      2. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(\mathsf{neg}\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right)\right) + \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)\right) \]
      3. neg-sub0N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(0 - \left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right) + \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)\right) \]
      4. associate-+l-N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{0 - \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      5. neg-sub0N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)}{x}\right)\right) \]
      6. mul-1-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      7. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
    8. Simplified98.8%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}}{x}\right)} \]
    9. Step-by-step derivation
      1. clear-numN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{\frac{x}{\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}}}\right)\right) \]
      2. associate-/r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{x} \cdot \left(\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\left(\frac{1}{x}\right), \left(\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right) \]
      4. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \left(\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right) \]
      5. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right)\right) \]
      6. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\left(\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      7. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \left(\frac{\frac{-1}{16}}{x \cdot x}\right)\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      8. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \mathsf{/.f64}\left(\frac{-1}{16}, \left(x \cdot x\right)\right)\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      9. *-lowering-*.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \mathsf{/.f64}\left(\frac{-1}{16}, \mathsf{*.f64}\left(x, x\right)\right)\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      10. *-lowering-*.f6498.8%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \mathsf{/.f64}\left(\frac{-1}{16}, \mathsf{*.f64}\left(x, x\right)\right)\right), \mathsf{*.f64}\left(x, x\right)\right)\right)\right)\right) \]
    10. Applied egg-rr98.8%

      \[\leadsto \log \color{blue}{\left(\frac{1}{x} \cdot \left(-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}\right)\right)} \]

    if -1.1000000000000001 < x < 0.023

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 0.023 < x

    1. Initial program 45.3%

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

        \[\leadsto \mathsf{log.f64}\left(\left(x + \sqrt{x \cdot x + 1}\right)\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(\sqrt{x \cdot x + 1}\right)\right)\right) \]
      3. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(\sqrt{1 + x \cdot x}\right)\right)\right) \]
      4. hypot-1-defN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(\mathsf{hypot}\left(1, x\right)\right)\right)\right) \]
      5. hypot-lowering-hypot.f64100.0%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{hypot.f64}\left(1, x\right)\right)\right) \]
    3. Simplified100.0%

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

Alternative 2: 99.7% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.1:\\ \;\;\;\;\log \left(\frac{1}{x} \cdot \left(-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}\right)\right)\\ \mathbf{elif}\;x \leq 0.98:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.1)
   (log (* (/ 1.0 x) (+ -0.5 (/ (+ 0.125 (/ -0.0625 (* x x))) (* x x)))))
   (if (<= x 0.98)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ (* x 2.0) (/ (+ 0.5 (/ -0.125 (* x x))) x))))))
double code(double x) {
	double tmp;
	if (x <= -1.1) {
		tmp = log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))));
	} else if (x <= 0.98) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.1d0)) then
        tmp = log(((1.0d0 / x) * ((-0.5d0) + ((0.125d0 + ((-0.0625d0) / (x * x))) / (x * x)))))
    else if (x <= 0.98d0) then
        tmp = x * (1.0d0 + ((x * x) * ((-0.16666666666666666d0) + (x * (x * (0.075d0 + ((x * x) * (-0.044642857142857144d0))))))))
    else
        tmp = log(((x * 2.0d0) + ((0.5d0 + ((-0.125d0) / (x * x))) / x)))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.1) {
		tmp = Math.log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))));
	} else if (x <= 0.98) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.1:
		tmp = math.log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))))
	elif x <= 0.98:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.1)
		tmp = log(Float64(Float64(1.0 / x) * Float64(-0.5 + Float64(Float64(0.125 + Float64(-0.0625 / Float64(x * x))) / Float64(x * x)))));
	elseif (x <= 0.98)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(Float64(x * 2.0) + Float64(Float64(0.5 + Float64(-0.125 / Float64(x * x))) / x)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.1)
		tmp = log(((1.0 / x) * (-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x)))));
	elseif (x <= 0.98)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.1], N[Log[N[(N[(1.0 / x), $MachinePrecision] * N[(-0.5 + N[(N[(0.125 + N[(-0.0625 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 0.98], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(x * 2.0), $MachinePrecision] + N[(N[(0.5 + N[(-0.125 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.1:\\
\;\;\;\;\log \left(\frac{1}{x} \cdot \left(-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}\right)\right)\\

\mathbf{elif}\;x \leq 0.98:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\log \left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.1000000000000001

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(-1 \cdot \frac{\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      2. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \left(\frac{0.125}{x \cdot x} + \frac{-0.0625}{x \cdot \left(x \cdot \left(x \cdot x\right)\right)}\right)}{x}\right)} \]
    6. Taylor expanded in x around inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)}{x}\right)}\right) \]
    7. Step-by-step derivation
      1. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right)\right)}{x}\right)\right) \]
      2. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(\mathsf{neg}\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right)\right) + \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)\right) \]
      3. neg-sub0N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(0 - \left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right) + \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)\right) \]
      4. associate-+l-N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{0 - \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      5. neg-sub0N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)}{x}\right)\right) \]
      6. mul-1-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      7. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
    8. Simplified98.8%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}}{x}\right)} \]
    9. Step-by-step derivation
      1. clear-numN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{\frac{x}{\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}}}\right)\right) \]
      2. associate-/r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{x} \cdot \left(\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\left(\frac{1}{x}\right), \left(\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right) \]
      4. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \left(\frac{-1}{2} + \frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right) \]
      5. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}}{x \cdot x}\right)\right)\right)\right) \]
      6. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\left(\frac{1}{8} + \frac{\frac{-1}{16}}{x \cdot x}\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      7. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \left(\frac{\frac{-1}{16}}{x \cdot x}\right)\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      8. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \mathsf{/.f64}\left(\frac{-1}{16}, \left(x \cdot x\right)\right)\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      9. *-lowering-*.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \mathsf{/.f64}\left(\frac{-1}{16}, \mathsf{*.f64}\left(x, x\right)\right)\right), \left(x \cdot x\right)\right)\right)\right)\right) \]
      10. *-lowering-*.f6498.8%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{1}{8}, \mathsf{/.f64}\left(\frac{-1}{16}, \mathsf{*.f64}\left(x, x\right)\right)\right), \mathsf{*.f64}\left(x, x\right)\right)\right)\right)\right) \]
    10. Applied egg-rr98.8%

      \[\leadsto \log \color{blue}{\left(\frac{1}{x} \cdot \left(-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}\right)\right)} \]

    if -1.1000000000000001 < x < 0.97999999999999998

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 0.97999999999999998 < x

    1. Initial program 45.3%

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

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(x \cdot \left(\left(2 + \frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) - \frac{\frac{1}{8}}{{x}^{4}}\right)\right)}\right) \]
    4. Simplified97.8%

      \[\leadsto \log \color{blue}{\left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 3: 99.7% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.1:\\ \;\;\;\;\log \left(\frac{-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}}{x}\right)\\ \mathbf{elif}\;x \leq 0.98:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.1)
   (log (/ (+ -0.5 (/ (+ 0.125 (/ -0.0625 (* x x))) (* x x))) x))
   (if (<= x 0.98)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ (* x 2.0) (/ (+ 0.5 (/ -0.125 (* x x))) x))))))
double code(double x) {
	double tmp;
	if (x <= -1.1) {
		tmp = log(((-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x))) / x));
	} else if (x <= 0.98) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.1d0)) then
        tmp = log((((-0.5d0) + ((0.125d0 + ((-0.0625d0) / (x * x))) / (x * x))) / x))
    else if (x <= 0.98d0) then
        tmp = x * (1.0d0 + ((x * x) * ((-0.16666666666666666d0) + (x * (x * (0.075d0 + ((x * x) * (-0.044642857142857144d0))))))))
    else
        tmp = log(((x * 2.0d0) + ((0.5d0 + ((-0.125d0) / (x * x))) / x)))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.1) {
		tmp = Math.log(((-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x))) / x));
	} else if (x <= 0.98) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.1:
		tmp = math.log(((-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x))) / x))
	elif x <= 0.98:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.1)
		tmp = log(Float64(Float64(-0.5 + Float64(Float64(0.125 + Float64(-0.0625 / Float64(x * x))) / Float64(x * x))) / x));
	elseif (x <= 0.98)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(Float64(x * 2.0) + Float64(Float64(0.5 + Float64(-0.125 / Float64(x * x))) / x)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.1)
		tmp = log(((-0.5 + ((0.125 + (-0.0625 / (x * x))) / (x * x))) / x));
	elseif (x <= 0.98)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.1], N[Log[N[(N[(-0.5 + N[(N[(0.125 + N[(-0.0625 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 0.98], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(x * 2.0), $MachinePrecision] + N[(N[(0.5 + N[(-0.125 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.1:\\
\;\;\;\;\log \left(\frac{-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}}{x}\right)\\

\mathbf{elif}\;x \leq 0.98:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\log \left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.1000000000000001

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(-1 \cdot \frac{\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      2. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
    5. Simplified98.8%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \left(\frac{0.125}{x \cdot x} + \frac{-0.0625}{x \cdot \left(x \cdot \left(x \cdot x\right)\right)}\right)}{x}\right)} \]
    6. Taylor expanded in x around inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)}{x}\right)}\right) \]
    7. Step-by-step derivation
      1. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right)\right)}{x}\right)\right) \]
      2. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(\mathsf{neg}\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right)\right) + \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)\right) \]
      3. neg-sub0N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(0 - \left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right)\right) + \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)\right) \]
      4. associate-+l-N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{0 - \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      5. neg-sub0N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)}{x}\right)\right) \]
      6. mul-1-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      7. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(-1 \cdot \left(\left(\frac{1}{2} + \frac{\frac{1}{16}}{{x}^{4}}\right) - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
    8. Simplified98.8%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \frac{0.125 + \frac{-0.0625}{x \cdot x}}{x \cdot x}}{x}\right)} \]

    if -1.1000000000000001 < x < 0.97999999999999998

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 0.97999999999999998 < x

    1. Initial program 45.3%

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

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(x \cdot \left(\left(2 + \frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) - \frac{\frac{1}{8}}{{x}^{4}}\right)\right)}\right) \]
    4. Simplified97.8%

      \[\leadsto \log \color{blue}{\left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 4: 99.7% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.12:\\ \;\;\;\;\log \left(\frac{-0.5 + \frac{0.125}{x \cdot x}}{x}\right)\\ \mathbf{elif}\;x \leq 0.98:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.12)
   (log (/ (+ -0.5 (/ 0.125 (* x x))) x))
   (if (<= x 0.98)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ (* x 2.0) (/ (+ 0.5 (/ -0.125 (* x x))) x))))))
double code(double x) {
	double tmp;
	if (x <= -1.12) {
		tmp = log(((-0.5 + (0.125 / (x * x))) / x));
	} else if (x <= 0.98) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.12d0)) then
        tmp = log((((-0.5d0) + (0.125d0 / (x * x))) / x))
    else if (x <= 0.98d0) then
        tmp = x * (1.0d0 + ((x * x) * ((-0.16666666666666666d0) + (x * (x * (0.075d0 + ((x * x) * (-0.044642857142857144d0))))))))
    else
        tmp = log(((x * 2.0d0) + ((0.5d0 + ((-0.125d0) / (x * x))) / x)))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.12) {
		tmp = Math.log(((-0.5 + (0.125 / (x * x))) / x));
	} else if (x <= 0.98) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.12:
		tmp = math.log(((-0.5 + (0.125 / (x * x))) / x))
	elif x <= 0.98:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.12)
		tmp = log(Float64(Float64(-0.5 + Float64(0.125 / Float64(x * x))) / x));
	elseif (x <= 0.98)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(Float64(x * 2.0) + Float64(Float64(0.5 + Float64(-0.125 / Float64(x * x))) / x)));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.12)
		tmp = log(((-0.5 + (0.125 / (x * x))) / x));
	elseif (x <= 0.98)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log(((x * 2.0) + ((0.5 + (-0.125 / (x * x))) / x)));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.12], N[Log[N[(N[(-0.5 + N[(0.125 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 0.98], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(x * 2.0), $MachinePrecision] + N[(N[(0.5 + N[(-0.125 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.12:\\
\;\;\;\;\log \left(\frac{-0.5 + \frac{0.125}{x \cdot x}}{x}\right)\\

\mathbf{elif}\;x \leq 0.98:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\log \left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.1200000000000001

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(-1 \cdot \frac{\frac{1}{2} - \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\frac{1}{2} - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      2. mul-1-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\frac{1}{2} - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)}{x}\right)\right) \]
      3. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\frac{1}{2} + \left(\mathsf{neg}\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)\right)\right)}{x}\right)\right) \]
      4. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\left(\mathsf{neg}\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right) + \frac{1}{2}\right)\right)}{x}\right)\right) \]
      5. distribute-neg-inN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)\right)\right) + \left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}{x}\right)\right) \]
      6. remove-double-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}{x}\right)\right) \]
      7. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \frac{1}{2}}{x}\right)\right) \]
      8. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \frac{1}{2}\right), x\right)\right) \]
      9. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\frac{1}{2}\right)\right)\right), x\right)\right) \]
      10. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \frac{-1}{2}\right), x\right)\right) \]
      11. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{-1}{2} + \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right), x\right)\right) \]
      12. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
      13. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{\frac{1}{8} \cdot 1}{{x}^{2}}\right)\right), x\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{\frac{1}{8}}{{x}^{2}}\right)\right), x\right)\right) \]
      15. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\frac{1}{8}, \left({x}^{2}\right)\right)\right), x\right)\right) \]
      16. unpow2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\frac{1}{8}, \left(x \cdot x\right)\right)\right), x\right)\right) \]
      17. *-lowering-*.f6498.4%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\frac{1}{8}, \mathsf{*.f64}\left(x, x\right)\right)\right), x\right)\right) \]
    5. Simplified98.4%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \frac{0.125}{x \cdot x}}{x}\right)} \]

    if -1.1200000000000001 < x < 0.97999999999999998

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 0.97999999999999998 < x

    1. Initial program 45.3%

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

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(x \cdot \left(\left(2 + \frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) - \frac{\frac{1}{8}}{{x}^{4}}\right)\right)}\right) \]
    4. Simplified97.8%

      \[\leadsto \log \color{blue}{\left(x \cdot 2 + \frac{0.5 + \frac{-0.125}{x \cdot x}}{x}\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 5: 99.6% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.12:\\ \;\;\;\;\log \left(\frac{-0.5 + \frac{0.125}{x \cdot x}}{x}\right)\\ \mathbf{elif}\;x \leq 1.05:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + \left(x - \frac{-0.5}{x}\right)\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.12)
   (log (/ (+ -0.5 (/ 0.125 (* x x))) x))
   (if (<= x 1.05)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ x (- x (/ -0.5 x)))))))
double code(double x) {
	double tmp;
	if (x <= -1.12) {
		tmp = log(((-0.5 + (0.125 / (x * x))) / x));
	} else if (x <= 1.05) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log((x + (x - (-0.5 / x))));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.12d0)) then
        tmp = log((((-0.5d0) + (0.125d0 / (x * x))) / x))
    else if (x <= 1.05d0) then
        tmp = x * (1.0d0 + ((x * x) * ((-0.16666666666666666d0) + (x * (x * (0.075d0 + ((x * x) * (-0.044642857142857144d0))))))))
    else
        tmp = log((x + (x - ((-0.5d0) / x))))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.12) {
		tmp = Math.log(((-0.5 + (0.125 / (x * x))) / x));
	} else if (x <= 1.05) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log((x + (x - (-0.5 / x))));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.12:
		tmp = math.log(((-0.5 + (0.125 / (x * x))) / x))
	elif x <= 1.05:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log((x + (x - (-0.5 / x))))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.12)
		tmp = log(Float64(Float64(-0.5 + Float64(0.125 / Float64(x * x))) / x));
	elseif (x <= 1.05)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(x + Float64(x - Float64(-0.5 / x))));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.12)
		tmp = log(((-0.5 + (0.125 / (x * x))) / x));
	elseif (x <= 1.05)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log((x + (x - (-0.5 / x))));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.12], N[Log[N[(N[(-0.5 + N[(0.125 / N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 1.05], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(x + N[(x - N[(-0.5 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.12:\\
\;\;\;\;\log \left(\frac{-0.5 + \frac{0.125}{x \cdot x}}{x}\right)\\

\mathbf{elif}\;x \leq 1.05:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\log \left(x + \left(x - \frac{-0.5}{x}\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.1200000000000001

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(-1 \cdot \frac{\frac{1}{2} - \frac{1}{8} \cdot \frac{1}{{x}^{2}}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{-1 \cdot \left(\frac{1}{2} - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)}{x}\right)\right) \]
      2. mul-1-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\frac{1}{2} - \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)}{x}\right)\right) \]
      3. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\frac{1}{2} + \left(\mathsf{neg}\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)\right)\right)}{x}\right)\right) \]
      4. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\mathsf{neg}\left(\left(\left(\mathsf{neg}\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right) + \frac{1}{2}\right)\right)}{x}\right)\right) \]
      5. distribute-neg-inN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right)\right)\right) + \left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}{x}\right)\right) \]
      6. remove-double-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}{x}\right)\right) \]
      7. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\left(\frac{\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \frac{1}{2}}{x}\right)\right) \]
      8. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}} - \frac{1}{2}\right), x\right)\right) \]
      9. sub-negN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \left(\mathsf{neg}\left(\frac{1}{2}\right)\right)\right), x\right)\right) \]
      10. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{1}{8} \cdot \frac{1}{{x}^{2}} + \frac{-1}{2}\right), x\right)\right) \]
      11. +-commutativeN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(\frac{-1}{2} + \frac{1}{8} \cdot \frac{1}{{x}^{2}}\right), x\right)\right) \]
      12. +-lowering-+.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{1}{8} \cdot \frac{1}{{x}^{2}}\right)\right), x\right)\right) \]
      13. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{\frac{1}{8} \cdot 1}{{x}^{2}}\right)\right), x\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \left(\frac{\frac{1}{8}}{{x}^{2}}\right)\right), x\right)\right) \]
      15. /-lowering-/.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\frac{1}{8}, \left({x}^{2}\right)\right)\right), x\right)\right) \]
      16. unpow2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\frac{1}{8}, \left(x \cdot x\right)\right)\right), x\right)\right) \]
      17. *-lowering-*.f6498.4%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\frac{1}{8}, \mathsf{*.f64}\left(x, x\right)\right)\right), x\right)\right) \]
    5. Simplified98.4%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5 + \frac{0.125}{x \cdot x}}{x}\right)} \]

    if -1.1200000000000001 < x < 1.05000000000000004

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 1.05000000000000004 < x

    1. Initial program 45.3%

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \color{blue}{\left(x \cdot \left(1 + \frac{1}{2} \cdot \frac{1}{{x}^{2}}\right)\right)}\right)\right) \]
    4. Step-by-step derivation
      1. distribute-rgt-inN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(1 \cdot x + \left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right) \]
      2. *-lft-identityN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(x + \left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right) \]
      3. cancel-sign-subN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(x - \left(\mathsf{neg}\left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right)\right) \cdot x\right)\right)\right) \]
      4. distribute-lft-neg-inN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(x - \left(\mathsf{neg}\left(\left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right)\right)\right) \]
      5. --lowering--.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right)\right)\right) \]
      6. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2} \cdot 1}{{x}^{2}} \cdot x\right)\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2}}{{x}^{2}} \cdot x\right)\right)\right)\right)\right) \]
      8. associate-*l/N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2} \cdot x}{{x}^{2}}\right)\right)\right)\right)\right) \]
      9. unpow2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2} \cdot x}{x \cdot x}\right)\right)\right)\right)\right) \]
      10. associate-/r*N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{\frac{1}{2} \cdot x}{x}}{x}\right)\right)\right)\right)\right) \]
      11. distribute-neg-frac2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{\frac{1}{2} \cdot x}{x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      12. *-lft-identityN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{\frac{1}{2} \cdot x}{1 \cdot x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      13. times-fracN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{\frac{1}{2}}{1} \cdot \frac{x}{x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{1}{2} \cdot \frac{x}{x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      15. *-inversesN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{1}{2} \cdot 1}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      16. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{1}{2}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      17. distribute-frac-neg2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2}}{x}\right)\right)\right)\right)\right) \]
      18. distribute-neg-fracN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\mathsf{neg}\left(\frac{1}{2}\right)}{x}\right)\right)\right)\right) \]
      19. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{-1}{2}}{x}\right)\right)\right)\right) \]
      20. /-lowering-/.f6497.4%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \mathsf{/.f64}\left(\frac{-1}{2}, x\right)\right)\right)\right) \]
    5. Simplified97.4%

      \[\leadsto \log \left(x + \color{blue}{\left(x - \frac{-0.5}{x}\right)}\right) \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 6: 99.5% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.3:\\ \;\;\;\;\log \left(\frac{-0.5}{x}\right)\\ \mathbf{elif}\;x \leq 1.05:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + \left(x - \frac{-0.5}{x}\right)\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.3)
   (log (/ -0.5 x))
   (if (<= x 1.05)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ x (- x (/ -0.5 x)))))))
double code(double x) {
	double tmp;
	if (x <= -1.3) {
		tmp = log((-0.5 / x));
	} else if (x <= 1.05) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log((x + (x - (-0.5 / x))));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.3d0)) then
        tmp = log(((-0.5d0) / x))
    else if (x <= 1.05d0) then
        tmp = x * (1.0d0 + ((x * x) * ((-0.16666666666666666d0) + (x * (x * (0.075d0 + ((x * x) * (-0.044642857142857144d0))))))))
    else
        tmp = log((x + (x - ((-0.5d0) / x))))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.3) {
		tmp = Math.log((-0.5 / x));
	} else if (x <= 1.05) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log((x + (x - (-0.5 / x))));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.3:
		tmp = math.log((-0.5 / x))
	elif x <= 1.05:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log((x + (x - (-0.5 / x))))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.3)
		tmp = log(Float64(-0.5 / x));
	elseif (x <= 1.05)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(x + Float64(x - Float64(-0.5 / x))));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.3)
		tmp = log((-0.5 / x));
	elseif (x <= 1.05)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log((x + (x - (-0.5 / x))));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.3], N[Log[N[(-0.5 / x), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 1.05], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(x + N[(x - N[(-0.5 / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.3:\\
\;\;\;\;\log \left(\frac{-0.5}{x}\right)\\

\mathbf{elif}\;x \leq 1.05:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\log \left(x + \left(x - \frac{-0.5}{x}\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.30000000000000004

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{\frac{-1}{2}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. /-lowering-/.f6497.3%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\frac{-1}{2}, x\right)\right) \]
    5. Simplified97.3%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5}{x}\right)} \]

    if -1.30000000000000004 < x < 1.05000000000000004

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 1.05000000000000004 < x

    1. Initial program 45.3%

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \color{blue}{\left(x \cdot \left(1 + \frac{1}{2} \cdot \frac{1}{{x}^{2}}\right)\right)}\right)\right) \]
    4. Step-by-step derivation
      1. distribute-rgt-inN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(1 \cdot x + \left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right) \]
      2. *-lft-identityN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(x + \left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right) \]
      3. cancel-sign-subN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(x - \left(\mathsf{neg}\left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right)\right) \cdot x\right)\right)\right) \]
      4. distribute-lft-neg-inN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \left(x - \left(\mathsf{neg}\left(\left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right)\right)\right) \]
      5. --lowering--.f64N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\left(\frac{1}{2} \cdot \frac{1}{{x}^{2}}\right) \cdot x\right)\right)\right)\right)\right) \]
      6. associate-*r/N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2} \cdot 1}{{x}^{2}} \cdot x\right)\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2}}{{x}^{2}} \cdot x\right)\right)\right)\right)\right) \]
      8. associate-*l/N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2} \cdot x}{{x}^{2}}\right)\right)\right)\right)\right) \]
      9. unpow2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2} \cdot x}{x \cdot x}\right)\right)\right)\right)\right) \]
      10. associate-/r*N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{\frac{1}{2} \cdot x}{x}}{x}\right)\right)\right)\right)\right) \]
      11. distribute-neg-frac2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{\frac{1}{2} \cdot x}{x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      12. *-lft-identityN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{\frac{1}{2} \cdot x}{1 \cdot x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      13. times-fracN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{\frac{1}{2}}{1} \cdot \frac{x}{x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      14. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{1}{2} \cdot \frac{x}{x}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      15. *-inversesN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{1}{2} \cdot 1}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      16. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{1}{2}}{\mathsf{neg}\left(x\right)}\right)\right)\right)\right) \]
      17. distribute-frac-neg2N/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\mathsf{neg}\left(\frac{\frac{1}{2}}{x}\right)\right)\right)\right)\right) \]
      18. distribute-neg-fracN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\mathsf{neg}\left(\frac{1}{2}\right)}{x}\right)\right)\right)\right) \]
      19. metadata-evalN/A

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \left(\frac{\frac{-1}{2}}{x}\right)\right)\right)\right) \]
      20. /-lowering-/.f6497.4%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \mathsf{\_.f64}\left(x, \mathsf{/.f64}\left(\frac{-1}{2}, x\right)\right)\right)\right) \]
    5. Simplified97.4%

      \[\leadsto \log \left(x + \color{blue}{\left(x - \frac{-0.5}{x}\right)}\right) \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 7: 99.4% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.3:\\ \;\;\;\;\log \left(\frac{-0.5}{x}\right)\\ \mathbf{elif}\;x \leq 1.3:\\ \;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + x\right)\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= x -1.3)
   (log (/ -0.5 x))
   (if (<= x 1.3)
     (*
      x
      (+
       1.0
       (*
        (* x x)
        (+
         -0.16666666666666666
         (* x (* x (+ 0.075 (* (* x x) -0.044642857142857144))))))))
     (log (+ x x)))))
double code(double x) {
	double tmp;
	if (x <= -1.3) {
		tmp = log((-0.5 / x));
	} else if (x <= 1.3) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = log((x + x));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-1.3d0)) then
        tmp = log(((-0.5d0) / x))
    else if (x <= 1.3d0) then
        tmp = x * (1.0d0 + ((x * x) * ((-0.16666666666666666d0) + (x * (x * (0.075d0 + ((x * x) * (-0.044642857142857144d0))))))))
    else
        tmp = log((x + x))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= -1.3) {
		tmp = Math.log((-0.5 / x));
	} else if (x <= 1.3) {
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	} else {
		tmp = Math.log((x + x));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= -1.3:
		tmp = math.log((-0.5 / x))
	elif x <= 1.3:
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))))
	else:
		tmp = math.log((x + x))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= -1.3)
		tmp = log(Float64(-0.5 / x));
	elseif (x <= 1.3)
		tmp = Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.16666666666666666 + Float64(x * Float64(x * Float64(0.075 + Float64(Float64(x * x) * -0.044642857142857144))))))));
	else
		tmp = log(Float64(x + x));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -1.3)
		tmp = log((-0.5 / x));
	elseif (x <= 1.3)
		tmp = x * (1.0 + ((x * x) * (-0.16666666666666666 + (x * (x * (0.075 + ((x * x) * -0.044642857142857144)))))));
	else
		tmp = log((x + x));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, -1.3], N[Log[N[(-0.5 / x), $MachinePrecision]], $MachinePrecision], If[LessEqual[x, 1.3], N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.16666666666666666 + N[(x * N[(x * N[(0.075 + N[(N[(x * x), $MachinePrecision] * -0.044642857142857144), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(x + x), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.3:\\
\;\;\;\;\log \left(\frac{-0.5}{x}\right)\\

\mathbf{elif}\;x \leq 1.3:\\
\;\;\;\;x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\log \left(x + x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if x < -1.30000000000000004

    1. Initial program 5.7%

      \[\log \left(x + \sqrt{x \cdot x + 1}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in x around -inf

      \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{\frac{-1}{2}}{x}\right)}\right) \]
    4. Step-by-step derivation
      1. /-lowering-/.f6497.3%

        \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\frac{-1}{2}, x\right)\right) \]
    5. Simplified97.3%

      \[\leadsto \log \color{blue}{\left(\frac{-0.5}{x}\right)} \]

    if -1.30000000000000004 < x < 1.30000000000000004

    1. Initial program 9.1%

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

      \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)} \]
    4. Step-by-step derivation
      1. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right) \]
      2. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)\right)}\right)\right) \]
      3. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) - \frac{1}{6}\right)}\right)\right)\right) \]
      4. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\left(x \cdot x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      5. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)} - \frac{1}{6}\right)\right)\right)\right) \]
      6. sub-negN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) + \frac{-1}{6}\right)\right)\right)\right) \]
      8. +-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \left(\frac{-1}{6} + \color{blue}{{x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right) \]
      9. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right) \]
      10. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40}} + \frac{-5}{112} \cdot {x}^{2}\right)\right)\right)\right)\right)\right) \]
      11. associate-*l*N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)\right)}\right)\right)\right)\right)\right) \]
      12. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \left(x \cdot \left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot \color{blue}{x}\right)\right)\right)\right)\right)\right) \]
      13. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \color{blue}{\left(\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right) \cdot x\right)}\right)\right)\right)\right)\right) \]
      14. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \left(x \cdot \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      15. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} + \frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right) \]
      16. +-lowering-+.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \color{blue}{\left(\frac{-5}{112} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right)\right)\right) \]
      17. *-commutativeN/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \left({x}^{2} \cdot \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      18. *-lowering-*.f64N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{-5}{112}}\right)\right)\right)\right)\right)\right)\right)\right) \]
      19. unpow2N/A

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
      20. *-lowering-*.f64100.0%

        \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{3}{40}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-5}{112}\right)\right)\right)\right)\right)\right)\right)\right) \]
    5. Simplified100.0%

      \[\leadsto \color{blue}{x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.16666666666666666 + x \cdot \left(x \cdot \left(0.075 + \left(x \cdot x\right) \cdot -0.044642857142857144\right)\right)\right)\right)} \]

    if 1.30000000000000004 < x

    1. Initial program 45.3%

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \color{blue}{x}\right)\right) \]
    4. Step-by-step derivation
      1. Simplified96.6%

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

    Alternative 8: 75.2% accurate, 1.9× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 1.32:\\ \;\;\;\;x \cdot \left(1 + x \cdot \left(x \cdot \left(-0.16666666666666666 + \left(x \cdot x\right) \cdot 0.075\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + x\right)\\ \end{array} \end{array} \]
    (FPCore (x)
     :precision binary64
     (if (<= x 1.32)
       (* x (+ 1.0 (* x (* x (+ -0.16666666666666666 (* (* x x) 0.075))))))
       (log (+ x x))))
    double code(double x) {
    	double tmp;
    	if (x <= 1.32) {
    		tmp = x * (1.0 + (x * (x * (-0.16666666666666666 + ((x * x) * 0.075)))));
    	} else {
    		tmp = log((x + x));
    	}
    	return tmp;
    }
    
    real(8) function code(x)
        real(8), intent (in) :: x
        real(8) :: tmp
        if (x <= 1.32d0) then
            tmp = x * (1.0d0 + (x * (x * ((-0.16666666666666666d0) + ((x * x) * 0.075d0)))))
        else
            tmp = log((x + x))
        end if
        code = tmp
    end function
    
    public static double code(double x) {
    	double tmp;
    	if (x <= 1.32) {
    		tmp = x * (1.0 + (x * (x * (-0.16666666666666666 + ((x * x) * 0.075)))));
    	} else {
    		tmp = Math.log((x + x));
    	}
    	return tmp;
    }
    
    def code(x):
    	tmp = 0
    	if x <= 1.32:
    		tmp = x * (1.0 + (x * (x * (-0.16666666666666666 + ((x * x) * 0.075)))))
    	else:
    		tmp = math.log((x + x))
    	return tmp
    
    function code(x)
    	tmp = 0.0
    	if (x <= 1.32)
    		tmp = Float64(x * Float64(1.0 + Float64(x * Float64(x * Float64(-0.16666666666666666 + Float64(Float64(x * x) * 0.075))))));
    	else
    		tmp = log(Float64(x + x));
    	end
    	return tmp
    end
    
    function tmp_2 = code(x)
    	tmp = 0.0;
    	if (x <= 1.32)
    		tmp = x * (1.0 + (x * (x * (-0.16666666666666666 + ((x * x) * 0.075)))));
    	else
    		tmp = log((x + x));
    	end
    	tmp_2 = tmp;
    end
    
    code[x_] := If[LessEqual[x, 1.32], N[(x * N[(1.0 + N[(x * N[(x * N[(-0.16666666666666666 + N[(N[(x * x), $MachinePrecision] * 0.075), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(x + x), $MachinePrecision]], $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;x \leq 1.32:\\
    \;\;\;\;x \cdot \left(1 + x \cdot \left(x \cdot \left(-0.16666666666666666 + \left(x \cdot x\right) \cdot 0.075\right)\right)\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\log \left(x + x\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if x < 1.32000000000000006

      1. Initial program 8.1%

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

        \[\leadsto \color{blue}{x \cdot \left(1 + {x}^{2} \cdot \left(\frac{3}{40} \cdot {x}^{2} - \frac{1}{6}\right)\right)} \]
      4. Step-by-step derivation
        1. *-lowering-*.f64N/A

          \[\leadsto \mathsf{*.f64}\left(x, \color{blue}{\left(1 + {x}^{2} \cdot \left(\frac{3}{40} \cdot {x}^{2} - \frac{1}{6}\right)\right)}\right) \]
        2. +-lowering-+.f64N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \color{blue}{\left({x}^{2} \cdot \left(\frac{3}{40} \cdot {x}^{2} - \frac{1}{6}\right)\right)}\right)\right) \]
        3. unpow2N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \left(\left(x \cdot x\right) \cdot \left(\color{blue}{\frac{3}{40} \cdot {x}^{2}} - \frac{1}{6}\right)\right)\right)\right) \]
        4. associate-*l*N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \left(x \cdot \color{blue}{\left(x \cdot \left(\frac{3}{40} \cdot {x}^{2} - \frac{1}{6}\right)\right)}\right)\right)\right) \]
        5. *-lowering-*.f64N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \color{blue}{\left(x \cdot \left(\frac{3}{40} \cdot {x}^{2} - \frac{1}{6}\right)\right)}\right)\right)\right) \]
        6. *-lowering-*.f64N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \color{blue}{\left(\frac{3}{40} \cdot {x}^{2} - \frac{1}{6}\right)}\right)\right)\right)\right) \]
        7. sub-negN/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \left(\frac{3}{40} \cdot {x}^{2} + \color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)}\right)\right)\right)\right)\right) \]
        8. metadata-evalN/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \left(\frac{3}{40} \cdot {x}^{2} + \frac{-1}{6}\right)\right)\right)\right)\right) \]
        9. +-commutativeN/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \left(\frac{-1}{6} + \color{blue}{\frac{3}{40} \cdot {x}^{2}}\right)\right)\right)\right)\right) \]
        10. +-lowering-+.f64N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{6}, \color{blue}{\left(\frac{3}{40} \cdot {x}^{2}\right)}\right)\right)\right)\right)\right) \]
        11. *-commutativeN/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{6}, \left({x}^{2} \cdot \color{blue}{\frac{3}{40}}\right)\right)\right)\right)\right)\right) \]
        12. *-lowering-*.f64N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(\left({x}^{2}\right), \color{blue}{\frac{3}{40}}\right)\right)\right)\right)\right)\right) \]
        13. unpow2N/A

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{3}{40}\right)\right)\right)\right)\right)\right) \]
        14. *-lowering-*.f6470.0%

          \[\leadsto \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(1, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{6}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{3}{40}\right)\right)\right)\right)\right)\right) \]
      5. Simplified70.0%

        \[\leadsto \color{blue}{x \cdot \left(1 + x \cdot \left(x \cdot \left(-0.16666666666666666 + \left(x \cdot x\right) \cdot 0.075\right)\right)\right)} \]

      if 1.32000000000000006 < x

      1. Initial program 45.3%

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

        \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(x, \color{blue}{x}\right)\right) \]
      4. Step-by-step derivation
        1. Simplified96.6%

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

      Alternative 9: 52.1% accurate, 207.0× speedup?

      \[\begin{array}{l} \\ x \end{array} \]
      (FPCore (x) :precision binary64 x)
      double code(double x) {
      	return x;
      }
      
      real(8) function code(x)
          real(8), intent (in) :: x
          code = x
      end function
      
      public static double code(double x) {
      	return x;
      }
      
      def code(x):
      	return x
      
      function code(x)
      	return x
      end
      
      function tmp = code(x)
      	tmp = x;
      end
      
      code[x_] := x
      
      \begin{array}{l}
      
      \\
      x
      \end{array}
      
      Derivation
      1. Initial program 18.1%

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

        \[\leadsto \color{blue}{x} \]
      4. Step-by-step derivation
        1. Simplified52.6%

          \[\leadsto \color{blue}{x} \]
        2. Add Preprocessing

        Developer Target 1: 30.2% accurate, 1.0× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{x \cdot x + 1}\\ \mathbf{if}\;x < 0:\\ \;\;\;\;\log \left(\frac{-1}{x - t\_0}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + t\_0\right)\\ \end{array} \end{array} \]
        (FPCore (x)
         :precision binary64
         (let* ((t_0 (sqrt (+ (* x x) 1.0))))
           (if (< x 0.0) (log (/ -1.0 (- x t_0))) (log (+ x t_0)))))
        double code(double x) {
        	double t_0 = sqrt(((x * x) + 1.0));
        	double tmp;
        	if (x < 0.0) {
        		tmp = log((-1.0 / (x - t_0)));
        	} else {
        		tmp = log((x + t_0));
        	}
        	return tmp;
        }
        
        real(8) function code(x)
            real(8), intent (in) :: x
            real(8) :: t_0
            real(8) :: tmp
            t_0 = sqrt(((x * x) + 1.0d0))
            if (x < 0.0d0) then
                tmp = log(((-1.0d0) / (x - t_0)))
            else
                tmp = log((x + t_0))
            end if
            code = tmp
        end function
        
        public static double code(double x) {
        	double t_0 = Math.sqrt(((x * x) + 1.0));
        	double tmp;
        	if (x < 0.0) {
        		tmp = Math.log((-1.0 / (x - t_0)));
        	} else {
        		tmp = Math.log((x + t_0));
        	}
        	return tmp;
        }
        
        def code(x):
        	t_0 = math.sqrt(((x * x) + 1.0))
        	tmp = 0
        	if x < 0.0:
        		tmp = math.log((-1.0 / (x - t_0)))
        	else:
        		tmp = math.log((x + t_0))
        	return tmp
        
        function code(x)
        	t_0 = sqrt(Float64(Float64(x * x) + 1.0))
        	tmp = 0.0
        	if (x < 0.0)
        		tmp = log(Float64(-1.0 / Float64(x - t_0)));
        	else
        		tmp = log(Float64(x + t_0));
        	end
        	return tmp
        end
        
        function tmp_2 = code(x)
        	t_0 = sqrt(((x * x) + 1.0));
        	tmp = 0.0;
        	if (x < 0.0)
        		tmp = log((-1.0 / (x - t_0)));
        	else
        		tmp = log((x + t_0));
        	end
        	tmp_2 = tmp;
        end
        
        code[x_] := Block[{t$95$0 = N[Sqrt[N[(N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]}, If[Less[x, 0.0], N[Log[N[(-1.0 / N[(x - t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[Log[N[(x + t$95$0), $MachinePrecision]], $MachinePrecision]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_0 := \sqrt{x \cdot x + 1}\\
        \mathbf{if}\;x < 0:\\
        \;\;\;\;\log \left(\frac{-1}{x - t\_0}\right)\\
        
        \mathbf{else}:\\
        \;\;\;\;\log \left(x + t\_0\right)\\
        
        
        \end{array}
        \end{array}
        

        Reproduce

        ?
        herbie shell --seed 2024139 
        (FPCore (x)
          :name "Hyperbolic arcsine"
          :precision binary64
        
          :alt
          (! :herbie-platform default (if (< x 0) (log (/ -1 (- x (sqrt (+ (* x x) 1))))) (log (+ x (sqrt (+ (* x x) 1))))))
        
          (log (+ x (sqrt (+ (* x x) 1.0)))))