Hyperbolic arc-(co)secant

Percentage Accurate: 100.0% → 100.0%
Time: 10.1s
Alternatives: 9
Speedup: 1.0×

Specification

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

\\
\log \left(\frac{1}{x} + \frac{\sqrt{1 - x \cdot x}}{x}\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: 100.0% accurate, 1.0× speedup?

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

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

Alternative 1: 100.0% accurate, 1.0× speedup?

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

\\
\log \left(\frac{1}{x} \cdot \left(1 + \sqrt{1 - x \cdot x}\right)\right)
\end{array}
Derivation
  1. Initial program 100.0%

    \[\log \left(\frac{1}{x} + \frac{\sqrt{1 - x \cdot x}}{x}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. div-invN/A

      \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{x} + \sqrt{1 - x \cdot x} \cdot \frac{1}{x}\right)\right) \]
    2. distribute-rgt1-inN/A

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

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

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \left(\sqrt{1 - x \cdot x}\right)\right)\right)\right) \]
    8. rem-square-sqrtN/A

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\left(\sqrt{1 - x \cdot x} \cdot \sqrt{1 - x \cdot x}\right)\right)\right)\right)\right) \]
    10. rem-square-sqrtN/A

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\mathsf{\_.f64}\left(1, \left(x \cdot x\right)\right)\right)\right)\right)\right) \]
    12. *-lowering-*.f64100.0%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\mathsf{\_.f64}\left(1, \mathsf{*.f64}\left(x, x\right)\right)\right)\right)\right)\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \log \color{blue}{\left(\frac{1}{x} \cdot \left(1 + \sqrt{1 - x \cdot x}\right)\right)} \]
  5. Add Preprocessing

Alternative 2: 100.0% accurate, 1.0× speedup?

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

\\
\log \left(\frac{1 + \sqrt{1 - x \cdot x}}{x}\right)
\end{array}
Derivation
  1. Initial program 100.0%

    \[\log \left(\frac{1}{x} + \frac{\sqrt{1 - x \cdot x}}{x}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. div-invN/A

      \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{x} + \sqrt{1 - x \cdot x} \cdot \frac{1}{x}\right)\right) \]
    2. distribute-rgt1-inN/A

      \[\leadsto \mathsf{log.f64}\left(\left(\left(\sqrt{1 - x \cdot x} + 1\right) \cdot \frac{1}{x}\right)\right) \]
    3. un-div-invN/A

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(1, \left(\sqrt{1 - x \cdot x}\right)\right), x\right)\right) \]
    7. rem-square-sqrtN/A

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\left(\sqrt{1 - x \cdot x} \cdot \sqrt{1 - x \cdot x}\right)\right)\right), x\right)\right) \]
    9. rem-square-sqrtN/A

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\mathsf{\_.f64}\left(1, \left(x \cdot x\right)\right)\right)\right), x\right)\right) \]
    11. *-lowering-*.f64100.0%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\mathsf{\_.f64}\left(1, \mathsf{*.f64}\left(x, x\right)\right)\right)\right), x\right)\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \log \color{blue}{\left(\frac{1 + \sqrt{1 - x \cdot x}}{x}\right)} \]
  5. Add Preprocessing

Alternative 3: 99.7% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \log \left(\frac{2 + \left(x \cdot x\right) \cdot \left(-0.5 + x \cdot \left(x \cdot \left(-0.125 + \left(x \cdot x\right) \cdot -0.0625\right)\right)\right)}{x}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (log
  (/
   (+ 2.0 (* (* x x) (+ -0.5 (* x (* x (+ -0.125 (* (* x x) -0.0625)))))))
   x)))
double code(double x) {
	return log(((2.0 + ((x * x) * (-0.5 + (x * (x * (-0.125 + ((x * x) * -0.0625))))))) / x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log(((2.0d0 + ((x * x) * ((-0.5d0) + (x * (x * ((-0.125d0) + ((x * x) * (-0.0625d0)))))))) / x))
end function
public static double code(double x) {
	return Math.log(((2.0 + ((x * x) * (-0.5 + (x * (x * (-0.125 + ((x * x) * -0.0625))))))) / x));
}
def code(x):
	return math.log(((2.0 + ((x * x) * (-0.5 + (x * (x * (-0.125 + ((x * x) * -0.0625))))))) / x))
function code(x)
	return log(Float64(Float64(2.0 + Float64(Float64(x * x) * Float64(-0.5 + Float64(x * Float64(x * Float64(-0.125 + Float64(Float64(x * x) * -0.0625))))))) / x))
end
function tmp = code(x)
	tmp = log(((2.0 + ((x * x) * (-0.5 + (x * (x * (-0.125 + ((x * x) * -0.0625))))))) / x));
end
code[x_] := N[Log[N[(N[(2.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.5 + N[(x * N[(x * N[(-0.125 + N[(N[(x * x), $MachinePrecision] * -0.0625), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(\frac{2 + \left(x \cdot x\right) \cdot \left(-0.5 + x \cdot \left(x \cdot \left(-0.125 + \left(x \cdot x\right) \cdot -0.0625\right)\right)\right)}{x}\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(2 + {x}^{2} \cdot \left({x}^{2} \cdot \left(\frac{-1}{16} \cdot {x}^{2} - \frac{1}{8}\right) - \frac{1}{2}\right)\right), x\right)\right) \]
  5. Simplified99.6%

    \[\leadsto \log \color{blue}{\left(\frac{2 + \left(x \cdot x\right) \cdot \left(-0.5 + x \cdot \left(x \cdot \left(-0.125 + \left(x \cdot x\right) \cdot -0.0625\right)\right)\right)}{x}\right)} \]
  6. Add Preprocessing

Alternative 4: 99.7% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \log \left(\frac{1}{x} \cdot \left(1 + \left(1 + \left(x \cdot x\right) \cdot \left(-0.5 + \left(x \cdot x\right) \cdot -0.125\right)\right)\right)\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (log (* (/ 1.0 x) (+ 1.0 (+ 1.0 (* (* x x) (+ -0.5 (* (* x x) -0.125))))))))
double code(double x) {
	return log(((1.0 / x) * (1.0 + (1.0 + ((x * x) * (-0.5 + ((x * x) * -0.125)))))));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log(((1.0d0 / x) * (1.0d0 + (1.0d0 + ((x * x) * ((-0.5d0) + ((x * x) * (-0.125d0))))))))
end function
public static double code(double x) {
	return Math.log(((1.0 / x) * (1.0 + (1.0 + ((x * x) * (-0.5 + ((x * x) * -0.125)))))));
}
def code(x):
	return math.log(((1.0 / x) * (1.0 + (1.0 + ((x * x) * (-0.5 + ((x * x) * -0.125)))))))
function code(x)
	return log(Float64(Float64(1.0 / x) * Float64(1.0 + Float64(1.0 + Float64(Float64(x * x) * Float64(-0.5 + Float64(Float64(x * x) * -0.125)))))))
end
function tmp = code(x)
	tmp = log(((1.0 / x) * (1.0 + (1.0 + ((x * x) * (-0.5 + ((x * x) * -0.125)))))));
end
code[x_] := N[Log[N[(N[(1.0 / x), $MachinePrecision] * N[(1.0 + N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.5 + N[(N[(x * x), $MachinePrecision] * -0.125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(\frac{1}{x} \cdot \left(1 + \left(1 + \left(x \cdot x\right) \cdot \left(-0.5 + \left(x \cdot x\right) \cdot -0.125\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 100.0%

    \[\log \left(\frac{1}{x} + \frac{\sqrt{1 - x \cdot x}}{x}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. div-invN/A

      \[\leadsto \mathsf{log.f64}\left(\left(\frac{1}{x} + \sqrt{1 - x \cdot x} \cdot \frac{1}{x}\right)\right) \]
    2. distribute-rgt1-inN/A

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

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

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \left(\sqrt{1 - x \cdot x}\right)\right)\right)\right) \]
    8. rem-square-sqrtN/A

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\left(\sqrt{1 - x \cdot x} \cdot \sqrt{1 - x \cdot x}\right)\right)\right)\right)\right) \]
    10. rem-square-sqrtN/A

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\mathsf{\_.f64}\left(1, \left(x \cdot x\right)\right)\right)\right)\right)\right) \]
    12. *-lowering-*.f64100.0%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{sqrt.f64}\left(\mathsf{\_.f64}\left(1, \mathsf{*.f64}\left(x, x\right)\right)\right)\right)\right)\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \log \color{blue}{\left(\frac{1}{x} \cdot \left(1 + \sqrt{1 - x \cdot x}\right)\right)} \]
  5. Taylor expanded in x around 0

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

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

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{+.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{*.f64}\left(\left(x \cdot x\right), \frac{-1}{8}\right)\right)\right), 1\right)\right)\right)\right) \]
    13. *-lowering-*.f6499.3%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(\mathsf{/.f64}\left(1, x\right), \mathsf{+.f64}\left(1, \mathsf{+.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{*.f64}\left(\mathsf{*.f64}\left(x, x\right), \frac{-1}{8}\right)\right)\right), 1\right)\right)\right)\right) \]
  7. Simplified99.3%

    \[\leadsto \log \left(\frac{1}{x} \cdot \left(1 + \color{blue}{\left(\left(x \cdot x\right) \cdot \left(-0.5 + \left(x \cdot x\right) \cdot -0.125\right) + 1\right)}\right)\right) \]
  8. Final simplification99.3%

    \[\leadsto \log \left(\frac{1}{x} \cdot \left(1 + \left(1 + \left(x \cdot x\right) \cdot \left(-0.5 + \left(x \cdot x\right) \cdot -0.125\right)\right)\right)\right) \]
  9. Add Preprocessing

Alternative 5: 99.7% accurate, 1.8× speedup?

\[\begin{array}{l} \\ 0 - \log \left(\frac{x}{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (- 0.0 (log (/ x (+ 2.0 (* x (* x (+ -0.5 (* x (* x -0.125))))))))))
double code(double x) {
	return 0.0 - log((x / (2.0 + (x * (x * (-0.5 + (x * (x * -0.125))))))));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 0.0d0 - log((x / (2.0d0 + (x * (x * ((-0.5d0) + (x * (x * (-0.125d0)))))))))
end function
public static double code(double x) {
	return 0.0 - Math.log((x / (2.0 + (x * (x * (-0.5 + (x * (x * -0.125))))))));
}
def code(x):
	return 0.0 - math.log((x / (2.0 + (x * (x * (-0.5 + (x * (x * -0.125))))))))
function code(x)
	return Float64(0.0 - log(Float64(x / Float64(2.0 + Float64(x * Float64(x * Float64(-0.5 + Float64(x * Float64(x * -0.125)))))))))
end
function tmp = code(x)
	tmp = 0.0 - log((x / (2.0 + (x * (x * (-0.5 + (x * (x * -0.125))))))));
end
code[x_] := N[(0.0 - N[Log[N[(x / N[(2.0 + N[(x * N[(x * N[(-0.5 + N[(x * N[(x * -0.125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
0 - \log \left(\frac{x}{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(2 + {x}^{2} \cdot \left(\frac{-1}{8} \cdot {x}^{2} - \frac{1}{2}\right)\right), x\right)\right) \]
  5. Simplified99.3%

    \[\leadsto \log \color{blue}{\left(\frac{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}{x}\right)} \]
  6. Step-by-step derivation
    1. clear-numN/A

      \[\leadsto \log \left(\frac{1}{\frac{x}{2 + x \cdot \left(x \cdot \left(\frac{-1}{2} + x \cdot \left(x \cdot \frac{-1}{8}\right)\right)\right)}}\right) \]
    2. log-recN/A

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

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

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

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

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

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

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

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

      \[\leadsto \mathsf{neg.f64}\left(\mathsf{log.f64}\left(\mathsf{/.f64}\left(x, \mathsf{+.f64}\left(2, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{*.f64}\left(x, \left(x \cdot \frac{-1}{8}\right)\right)\right)\right)\right)\right)\right)\right)\right) \]
    11. *-lowering-*.f6499.3%

      \[\leadsto \mathsf{neg.f64}\left(\mathsf{log.f64}\left(\mathsf{/.f64}\left(x, \mathsf{+.f64}\left(2, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{*.f64}\left(x, \mathsf{*.f64}\left(x, \frac{-1}{8}\right)\right)\right)\right)\right)\right)\right)\right)\right) \]
  7. Applied egg-rr99.3%

    \[\leadsto \color{blue}{-\log \left(\frac{x}{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}\right)} \]
  8. Final simplification99.3%

    \[\leadsto 0 - \log \left(\frac{x}{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}\right) \]
  9. Add Preprocessing

Alternative 6: 99.7% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \log \left(\frac{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}{x}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (log (/ (+ 2.0 (* x (* x (+ -0.5 (* x (* x -0.125)))))) x)))
double code(double x) {
	return log(((2.0 + (x * (x * (-0.5 + (x * (x * -0.125)))))) / x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log(((2.0d0 + (x * (x * ((-0.5d0) + (x * (x * (-0.125d0))))))) / x))
end function
public static double code(double x) {
	return Math.log(((2.0 + (x * (x * (-0.5 + (x * (x * -0.125)))))) / x));
}
def code(x):
	return math.log(((2.0 + (x * (x * (-0.5 + (x * (x * -0.125)))))) / x))
function code(x)
	return log(Float64(Float64(2.0 + Float64(x * Float64(x * Float64(-0.5 + Float64(x * Float64(x * -0.125)))))) / x))
end
function tmp = code(x)
	tmp = log(((2.0 + (x * (x * (-0.5 + (x * (x * -0.125)))))) / x));
end
code[x_] := N[Log[N[(N[(2.0 + N[(x * N[(x * N[(-0.5 + N[(x * N[(x * -0.125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(\frac{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}{x}\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\left(2 + {x}^{2} \cdot \left(\frac{-1}{8} \cdot {x}^{2} - \frac{1}{2}\right)\right), x\right)\right) \]
  5. Simplified99.3%

    \[\leadsto \log \color{blue}{\left(\frac{2 + x \cdot \left(x \cdot \left(-0.5 + x \cdot \left(x \cdot -0.125\right)\right)\right)}{x}\right)} \]
  6. Add Preprocessing

Alternative 7: 99.5% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \log \left(\frac{2 + \left(x \cdot x\right) \cdot -0.5}{x}\right) \end{array} \]
(FPCore (x) :precision binary64 (log (/ (+ 2.0 (* (* x x) -0.5)) x)))
double code(double x) {
	return log(((2.0 + ((x * x) * -0.5)) / x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log(((2.0d0 + ((x * x) * (-0.5d0))) / x))
end function
public static double code(double x) {
	return Math.log(((2.0 + ((x * x) * -0.5)) / x));
}
def code(x):
	return math.log(((2.0 + ((x * x) * -0.5)) / x))
function code(x)
	return log(Float64(Float64(2.0 + Float64(Float64(x * x) * -0.5)) / x))
end
function tmp = code(x)
	tmp = log(((2.0 + ((x * x) * -0.5)) / x));
end
code[x_] := N[Log[N[(N[(2.0 + N[(N[(x * x), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(\frac{2 + \left(x \cdot x\right) \cdot -0.5}{x}\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

    \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{2 + \frac{-1}{2} \cdot {x}^{2}}{x}\right)}\right) \]
  4. Step-by-step derivation
    1. /-lowering-/.f64N/A

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(2, \mathsf{*.f64}\left(\frac{-1}{2}, \left(x \cdot x\right)\right)\right), x\right)\right) \]
    5. *-lowering-*.f6498.9%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(2, \mathsf{*.f64}\left(\frac{-1}{2}, \mathsf{*.f64}\left(x, x\right)\right)\right), x\right)\right) \]
  5. Simplified98.9%

    \[\leadsto \log \color{blue}{\left(\frac{2 + -0.5 \cdot \left(x \cdot x\right)}{x}\right)} \]
  6. Final simplification98.9%

    \[\leadsto \log \left(\frac{2 + \left(x \cdot x\right) \cdot -0.5}{x}\right) \]
  7. Add Preprocessing

Alternative 8: 99.5% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \log \left(\frac{2}{x} + x \cdot -0.5\right) \end{array} \]
(FPCore (x) :precision binary64 (log (+ (/ 2.0 x) (* x -0.5))))
double code(double x) {
	return log(((2.0 / x) + (x * -0.5)));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log(((2.0d0 / x) + (x * (-0.5d0))))
end function
public static double code(double x) {
	return Math.log(((2.0 / x) + (x * -0.5)));
}
def code(x):
	return math.log(((2.0 / x) + (x * -0.5)))
function code(x)
	return log(Float64(Float64(2.0 / x) + Float64(x * -0.5)))
end
function tmp = code(x)
	tmp = log(((2.0 / x) + (x * -0.5)));
end
code[x_] := N[Log[N[(N[(2.0 / x), $MachinePrecision] + N[(x * -0.5), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(\frac{2}{x} + x \cdot -0.5\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

    \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{2 + \frac{-1}{2} \cdot {x}^{2}}{x}\right)}\right) \]
  4. Step-by-step derivation
    1. /-lowering-/.f64N/A

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(2, \mathsf{*.f64}\left(\frac{-1}{2}, \left(x \cdot x\right)\right)\right), x\right)\right) \]
    5. *-lowering-*.f6498.9%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(\mathsf{+.f64}\left(2, \mathsf{*.f64}\left(\frac{-1}{2}, \mathsf{*.f64}\left(x, x\right)\right)\right), x\right)\right) \]
  5. Simplified98.9%

    \[\leadsto \log \color{blue}{\left(\frac{2 + -0.5 \cdot \left(x \cdot x\right)}{x}\right)} \]
  6. Taylor expanded in x around inf

    \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(x \cdot \left(2 \cdot \frac{1}{{x}^{2}} - \frac{1}{2}\right)\right)}\right) \]
  7. Step-by-step derivation
    1. *-lowering-*.f64N/A

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

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

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

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

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

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(2, \left(x \cdot x\right)\right)\right)\right)\right) \]
    10. *-lowering-*.f6453.1%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{*.f64}\left(x, \mathsf{+.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(2, \mathsf{*.f64}\left(x, x\right)\right)\right)\right)\right) \]
  8. Simplified53.1%

    \[\leadsto \log \color{blue}{\left(x \cdot \left(-0.5 + \frac{2}{x \cdot x}\right)\right)} \]
  9. Step-by-step derivation
    1. +-commutativeN/A

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

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\left(2 \cdot \left(\frac{1}{x \cdot x} \cdot x\right) + x \cdot \frac{-1}{2}\right)\right) \]
    6. pow2N/A

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

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

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

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

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

      \[\leadsto \mathsf{log.f64}\left(\left(2 \cdot \frac{1}{x} + x \cdot \frac{-1}{2}\right)\right) \]
    12. div-invN/A

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

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

      \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(2, x\right), \left(x \cdot \frac{-1}{2}\right)\right)\right) \]
    15. *-lowering-*.f6498.9%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(2, x\right), \mathsf{*.f64}\left(x, \frac{-1}{2}\right)\right)\right) \]
  10. Applied egg-rr98.9%

    \[\leadsto \log \color{blue}{\left(\frac{2}{x} + x \cdot -0.5\right)} \]
  11. Add Preprocessing

Alternative 9: 99.1% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \log \left(\frac{2}{x}\right) \end{array} \]
(FPCore (x) :precision binary64 (log (/ 2.0 x)))
double code(double x) {
	return log((2.0 / x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = log((2.0d0 / x))
end function
public static double code(double x) {
	return Math.log((2.0 / x));
}
def code(x):
	return math.log((2.0 / x))
function code(x)
	return log(Float64(2.0 / x))
end
function tmp = code(x)
	tmp = log((2.0 / x));
end
code[x_] := N[Log[N[(2.0 / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\log \left(\frac{2}{x}\right)
\end{array}
Derivation
  1. Initial program 100.0%

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

    \[\leadsto \mathsf{log.f64}\left(\color{blue}{\left(\frac{2}{x}\right)}\right) \]
  4. Step-by-step derivation
    1. /-lowering-/.f6498.3%

      \[\leadsto \mathsf{log.f64}\left(\mathsf{/.f64}\left(2, x\right)\right) \]
  5. Simplified98.3%

    \[\leadsto \log \color{blue}{\left(\frac{2}{x}\right)} \]
  6. Add Preprocessing

Reproduce

?
herbie shell --seed 2024191 
(FPCore (x)
  :name "Hyperbolic arc-(co)secant"
  :precision binary64
  (log (+ (/ 1.0 x) (/ (sqrt (- 1.0 (* x x))) x))))