math.sqrt on complex, imaginary part, im greater than 0 branch

Percentage Accurate: 41.4% → 89.9%
Time: 9.0s
Alternatives: 8
Speedup: 2.2×

Specification

?
\[im > 0\]
\[\begin{array}{l} \\ 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \end{array} \]
(FPCore (re im)
 :precision binary64
 (* 0.5 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))
double code(double re, double im) {
	return 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re)));
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    code = 0.5d0 * sqrt((2.0d0 * (sqrt(((re * re) + (im * im))) - re)))
end function
public static double code(double re, double im) {
	return 0.5 * Math.sqrt((2.0 * (Math.sqrt(((re * re) + (im * im))) - re)));
}
def code(re, im):
	return 0.5 * math.sqrt((2.0 * (math.sqrt(((re * re) + (im * im))) - re)))
function code(re, im)
	return Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im * im))) - re))))
end
function tmp = code(re, im)
	tmp = 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re)));
end
code[re_, im_] := N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\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 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 41.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \end{array} \]
(FPCore (re im)
 :precision binary64
 (* 0.5 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))
double code(double re, double im) {
	return 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re)));
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    code = 0.5d0 * sqrt((2.0d0 * (sqrt(((re * re) + (im * im))) - re)))
end function
public static double code(double re, double im) {
	return 0.5 * Math.sqrt((2.0 * (Math.sqrt(((re * re) + (im * im))) - re)));
}
def code(re, im):
	return 0.5 * math.sqrt((2.0 * (math.sqrt(((re * re) + (im * im))) - re)))
function code(re, im)
	return Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im * im))) - re))))
end
function tmp = code(re, im)
	tmp = 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re)));
end
code[re_, im_] := N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}
\end{array}

Alternative 1: 89.9% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \leq 0:\\ \;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\mathsf{hypot}\left(re, im\right) - re\right)}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re))) 0.0)
   (* (sqrt (/ 1.0 re)) (* im 0.5))
   (* 0.5 (sqrt (* 2.0 (- (hypot re im) re))))))
double code(double re, double im) {
	double tmp;
	if (sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re))) <= 0.0) {
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	} else {
		tmp = 0.5 * sqrt((2.0 * (hypot(re, im) - re)));
	}
	return tmp;
}
public static double code(double re, double im) {
	double tmp;
	if (Math.sqrt((2.0 * (Math.sqrt(((re * re) + (im * im))) - re))) <= 0.0) {
		tmp = Math.sqrt((1.0 / re)) * (im * 0.5);
	} else {
		tmp = 0.5 * Math.sqrt((2.0 * (Math.hypot(re, im) - re)));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if math.sqrt((2.0 * (math.sqrt(((re * re) + (im * im))) - re))) <= 0.0:
		tmp = math.sqrt((1.0 / re)) * (im * 0.5)
	else:
		tmp = 0.5 * math.sqrt((2.0 * (math.hypot(re, im) - re)))
	return tmp
function code(re, im)
	tmp = 0.0
	if (sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im * im))) - re))) <= 0.0)
		tmp = Float64(sqrt(Float64(1.0 / re)) * Float64(im * 0.5));
	else
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(hypot(re, im) - re))));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re))) <= 0.0)
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	else
		tmp = 0.5 * sqrt((2.0 * (hypot(re, im) - re)));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], 0.0], N[(N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision] * N[(im * 0.5), $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[re ^ 2 + im ^ 2], $MachinePrecision] - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \leq 0:\\
\;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\

\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\mathsf{hypot}\left(re, im\right) - re\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (sqrt.f64 (*.f64 #s(literal 2 binary64) (-.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re))) < 0.0

    1. Initial program 5.5%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. associate-*l*N/A

        \[\leadsto \color{blue}{\left(im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \sqrt{\frac{1}{re}}\right)\right)} \cdot \frac{1}{2} \]
      3. *-commutativeN/A

        \[\leadsto \left(im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)}\right) \cdot \frac{1}{2} \]
      4. associate-*r*N/A

        \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      5. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      6. lower-*.f64N/A

        \[\leadsto \color{blue}{im \cdot \left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      8. associate-*r*N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{2}\right)} \cdot \frac{1}{2}\right) \]
      9. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      10. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      12. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      13. lower-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      14. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      15. lower-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      16. lower-sqrt.f6498.9

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot 0.5\right)\right) \]
    5. Applied rewrites98.9%

      \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\sqrt{2} \cdot 0.5\right)\right)} \]
    6. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      2. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      4. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot \frac{1}{2}\right)\right) \]
      5. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      6. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)} \]
      7. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      8. pow1/2N/A

        \[\leadsto im \cdot \left(\color{blue}{{\left(\frac{1}{re}\right)}^{\frac{1}{2}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      9. sqr-powN/A

        \[\leadsto im \cdot \left(\color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot {\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      10. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      12. lift-/.f64N/A

        \[\leadsto im \cdot \left({\color{blue}{\left(\frac{1}{re}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      13. inv-powN/A

        \[\leadsto im \cdot \left({\color{blue}{\left({re}^{-1}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      14. pow-powN/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      15. lower-pow.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      16. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\left(-1 \cdot \color{blue}{\frac{1}{4}}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      17. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\color{blue}{\frac{-1}{4}}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      18. lift-*.f64N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right)\right)\right) \]
      19. associate-*r*N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \frac{1}{2}\right)}\right)\right) \]
    7. Applied rewrites99.2%

      \[\leadsto im \cdot \color{blue}{\left({re}^{-0.25} \cdot \left({re}^{-0.25} \cdot 0.5\right)\right)} \]
    8. Taylor expanded in im around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(im \cdot \sqrt{\frac{1}{re}}\right)} \]
    9. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(im \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot im\right)} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      4. lower-*.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      5. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      6. lower-/.f64N/A

        \[\leadsto \sqrt{\color{blue}{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      7. lower-*.f6499.7

        \[\leadsto \sqrt{\frac{1}{re}} \cdot \color{blue}{\left(im \cdot 0.5\right)} \]
    10. Applied rewrites99.7%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)} \]

    if 0.0 < (sqrt.f64 (*.f64 #s(literal 2 binary64) (-.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re)))

    1. Initial program 43.7%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lower-hypot.f6491.6

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\mathsf{hypot}\left(re, im\right)} - re\right)} \]
    4. Applied rewrites91.6%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\mathsf{hypot}\left(re, im\right)} - re\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 2: 75.4% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\\ \mathbf{if}\;t\_0 \leq 0:\\ \;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\ \mathbf{elif}\;t\_0 \leq 10^{+77}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\ \mathbf{else}:\\ \;\;\;\;\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (let* ((t_0 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))
   (if (<= t_0 0.0)
     (* (sqrt (/ 1.0 re)) (* im 0.5))
     (if (<= t_0 1e+77)
       (* 0.5 (sqrt (* 2.0 (- (sqrt (fma re re (* im im))) re))))
       (* (* 0.5 (sqrt (- im re))) (sqrt 2.0))))))
double code(double re, double im) {
	double t_0 = sqrt((2.0 * (sqrt(((re * re) + (im * im))) - re)));
	double tmp;
	if (t_0 <= 0.0) {
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	} else if (t_0 <= 1e+77) {
		tmp = 0.5 * sqrt((2.0 * (sqrt(fma(re, re, (im * im))) - re)));
	} else {
		tmp = (0.5 * sqrt((im - re))) * sqrt(2.0);
	}
	return tmp;
}
function code(re, im)
	t_0 = sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im * im))) - re)))
	tmp = 0.0
	if (t_0 <= 0.0)
		tmp = Float64(sqrt(Float64(1.0 / re)) * Float64(im * 0.5));
	elseif (t_0 <= 1e+77)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(fma(re, re, Float64(im * im))) - re))));
	else
		tmp = Float64(Float64(0.5 * sqrt(Float64(im - re))) * sqrt(2.0));
	end
	return tmp
end
code[re_, im_] := Block[{t$95$0 = N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[t$95$0, 0.0], N[(N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision] * N[(im * 0.5), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$0, 1e+77], N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(re * re + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(0.5 * N[Sqrt[N[(im - re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\\
\mathbf{if}\;t\_0 \leq 0:\\
\;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\

\mathbf{elif}\;t\_0 \leq 10^{+77}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\

\mathbf{else}:\\
\;\;\;\;\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (sqrt.f64 (*.f64 #s(literal 2 binary64) (-.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re))) < 0.0

    1. Initial program 5.5%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. associate-*l*N/A

        \[\leadsto \color{blue}{\left(im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \sqrt{\frac{1}{re}}\right)\right)} \cdot \frac{1}{2} \]
      3. *-commutativeN/A

        \[\leadsto \left(im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)}\right) \cdot \frac{1}{2} \]
      4. associate-*r*N/A

        \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      5. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      6. lower-*.f64N/A

        \[\leadsto \color{blue}{im \cdot \left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      8. associate-*r*N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{2}\right)} \cdot \frac{1}{2}\right) \]
      9. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      10. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      12. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      13. lower-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      14. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      15. lower-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      16. lower-sqrt.f6498.9

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot 0.5\right)\right) \]
    5. Applied rewrites98.9%

      \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\sqrt{2} \cdot 0.5\right)\right)} \]
    6. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      2. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      4. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot \frac{1}{2}\right)\right) \]
      5. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      6. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)} \]
      7. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      8. pow1/2N/A

        \[\leadsto im \cdot \left(\color{blue}{{\left(\frac{1}{re}\right)}^{\frac{1}{2}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      9. sqr-powN/A

        \[\leadsto im \cdot \left(\color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot {\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      10. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      12. lift-/.f64N/A

        \[\leadsto im \cdot \left({\color{blue}{\left(\frac{1}{re}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      13. inv-powN/A

        \[\leadsto im \cdot \left({\color{blue}{\left({re}^{-1}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      14. pow-powN/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      15. lower-pow.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      16. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\left(-1 \cdot \color{blue}{\frac{1}{4}}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      17. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\color{blue}{\frac{-1}{4}}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      18. lift-*.f64N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right)\right)\right) \]
      19. associate-*r*N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \frac{1}{2}\right)}\right)\right) \]
    7. Applied rewrites99.2%

      \[\leadsto im \cdot \color{blue}{\left({re}^{-0.25} \cdot \left({re}^{-0.25} \cdot 0.5\right)\right)} \]
    8. Taylor expanded in im around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(im \cdot \sqrt{\frac{1}{re}}\right)} \]
    9. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(im \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot im\right)} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      4. lower-*.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      5. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      6. lower-/.f64N/A

        \[\leadsto \sqrt{\color{blue}{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      7. lower-*.f6499.7

        \[\leadsto \sqrt{\frac{1}{re}} \cdot \color{blue}{\left(im \cdot 0.5\right)} \]
    10. Applied rewrites99.7%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)} \]

    if 0.0 < (sqrt.f64 (*.f64 #s(literal 2 binary64) (-.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re))) < 9.99999999999999983e76

    1. Initial program 91.3%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{re \cdot re} + im \cdot im} - re\right)} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + \color{blue}{im \cdot im}} - re\right)} \]
      3. lift-+.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{re \cdot re + im \cdot im}} - re\right)} \]
      4. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\color{blue}{\sqrt{re \cdot re + im \cdot im}} - re\right)} \]
      5. lift--.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(\sqrt{re \cdot re + im \cdot im} - re\right)}} \]
      6. lift-*.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}} \]
      7. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}} \]
      8. *-commutativeN/A

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \cdot \frac{1}{2}} \]
      9. lower-*.f6491.3

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \cdot 0.5} \]
    4. Applied rewrites91.3%

      \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)} \cdot 0.5} \]

    if 9.99999999999999983e76 < (sqrt.f64 (*.f64 #s(literal 2 binary64) (-.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re)))

    1. Initial program 3.6%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + -1 \cdot re\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im + \color{blue}{\left(\mathsf{neg}\left(re\right)\right)}\right)} \]
      2. unsub-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      3. lower--.f6461.9

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Applied rewrites61.9%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    6. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(im - re\right) \cdot 2}} \]
      3. sqrt-prodN/A

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left(\sqrt{im - re} \cdot \sqrt{2}\right)} \]
      4. pow1/2N/A

        \[\leadsto \frac{1}{2} \cdot \left(\color{blue}{{\left(im - re\right)}^{\frac{1}{2}}} \cdot \sqrt{2}\right) \]
      5. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{2} \cdot \left({\left(im - re\right)}^{\frac{1}{2}} \cdot \color{blue}{\sqrt{2}}\right) \]
      6. associate-*r*N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot {\left(im - re\right)}^{\frac{1}{2}}\right) \cdot \sqrt{2}} \]
      7. *-commutativeN/A

        \[\leadsto \color{blue}{\left({\left(im - re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right)} \cdot \sqrt{2} \]
      8. lower-*.f64N/A

        \[\leadsto \color{blue}{\left({\left(im - re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right) \cdot \sqrt{2}} \]
      9. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot {\left(im - re\right)}^{\frac{1}{2}}\right)} \cdot \sqrt{2} \]
      10. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot {\left(im - re\right)}^{\frac{1}{2}}\right)} \cdot \sqrt{2} \]
      11. pow1/2N/A

        \[\leadsto \left(\frac{1}{2} \cdot \color{blue}{\sqrt{im - re}}\right) \cdot \sqrt{2} \]
      12. lower-sqrt.f6462.2

        \[\leadsto \left(0.5 \cdot \color{blue}{\sqrt{im - re}}\right) \cdot \sqrt{2} \]
    7. Applied rewrites62.2%

      \[\leadsto \color{blue}{\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification79.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \leq 0:\\ \;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\ \mathbf{elif}\;\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \leq 10^{+77}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\ \mathbf{else}:\\ \;\;\;\;\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 76.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 7.2 \cdot 10^{-24}:\\ \;\;\;\;\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.8e+112)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re 7.2e-24)
     (* (* 0.5 (sqrt (- im re))) (sqrt 2.0))
     (* (sqrt (/ 1.0 re)) (* im 0.5)))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= 7.2e-24) {
		tmp = (0.5 * sqrt((im - re))) * sqrt(2.0);
	} else {
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-1.8d+112)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else if (re <= 7.2d-24) then
        tmp = (0.5d0 * sqrt((im - re))) * sqrt(2.0d0)
    else
        tmp = sqrt((1.0d0 / re)) * (im * 0.5d0)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else if (re <= 7.2e-24) {
		tmp = (0.5 * Math.sqrt((im - re))) * Math.sqrt(2.0);
	} else {
		tmp = Math.sqrt((1.0 / re)) * (im * 0.5);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.8e+112:
		tmp = 0.5 * math.sqrt((re * -4.0))
	elif re <= 7.2e-24:
		tmp = (0.5 * math.sqrt((im - re))) * math.sqrt(2.0)
	else:
		tmp = math.sqrt((1.0 / re)) * (im * 0.5)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.8e+112)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= 7.2e-24)
		tmp = Float64(Float64(0.5 * sqrt(Float64(im - re))) * sqrt(2.0));
	else
		tmp = Float64(sqrt(Float64(1.0 / re)) * Float64(im * 0.5));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.8e+112)
		tmp = 0.5 * sqrt((re * -4.0));
	elseif (re <= 7.2e-24)
		tmp = (0.5 * sqrt((im - re))) * sqrt(2.0);
	else
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.8e+112], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 7.2e-24], N[(N[(0.5 * N[Sqrt[N[(im - re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision] * N[(im * 0.5), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq 7.2 \cdot 10^{-24}:\\
\;\;\;\;\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -1.8e112

    1. Initial program 21.5%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -inf

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-4 \cdot re}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6481.9

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Applied rewrites81.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]

    if -1.8e112 < re < 7.2000000000000002e-24

    1. Initial program 53.8%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + -1 \cdot re\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im + \color{blue}{\left(\mathsf{neg}\left(re\right)\right)}\right)} \]
      2. unsub-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      3. lower--.f6477.8

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Applied rewrites77.8%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    6. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(im - re\right) \cdot 2}} \]
      3. sqrt-prodN/A

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left(\sqrt{im - re} \cdot \sqrt{2}\right)} \]
      4. pow1/2N/A

        \[\leadsto \frac{1}{2} \cdot \left(\color{blue}{{\left(im - re\right)}^{\frac{1}{2}}} \cdot \sqrt{2}\right) \]
      5. lift-sqrt.f64N/A

        \[\leadsto \frac{1}{2} \cdot \left({\left(im - re\right)}^{\frac{1}{2}} \cdot \color{blue}{\sqrt{2}}\right) \]
      6. associate-*r*N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot {\left(im - re\right)}^{\frac{1}{2}}\right) \cdot \sqrt{2}} \]
      7. *-commutativeN/A

        \[\leadsto \color{blue}{\left({\left(im - re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right)} \cdot \sqrt{2} \]
      8. lower-*.f64N/A

        \[\leadsto \color{blue}{\left({\left(im - re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right) \cdot \sqrt{2}} \]
      9. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot {\left(im - re\right)}^{\frac{1}{2}}\right)} \cdot \sqrt{2} \]
      10. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot {\left(im - re\right)}^{\frac{1}{2}}\right)} \cdot \sqrt{2} \]
      11. pow1/2N/A

        \[\leadsto \left(\frac{1}{2} \cdot \color{blue}{\sqrt{im - re}}\right) \cdot \sqrt{2} \]
      12. lower-sqrt.f6477.9

        \[\leadsto \left(0.5 \cdot \color{blue}{\sqrt{im - re}}\right) \cdot \sqrt{2} \]
    7. Applied rewrites77.9%

      \[\leadsto \color{blue}{\left(0.5 \cdot \sqrt{im - re}\right) \cdot \sqrt{2}} \]

    if 7.2000000000000002e-24 < re

    1. Initial program 9.7%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. associate-*l*N/A

        \[\leadsto \color{blue}{\left(im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \sqrt{\frac{1}{re}}\right)\right)} \cdot \frac{1}{2} \]
      3. *-commutativeN/A

        \[\leadsto \left(im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)}\right) \cdot \frac{1}{2} \]
      4. associate-*r*N/A

        \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      5. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      6. lower-*.f64N/A

        \[\leadsto \color{blue}{im \cdot \left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      8. associate-*r*N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{2}\right)} \cdot \frac{1}{2}\right) \]
      9. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      10. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      12. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      13. lower-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      14. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      15. lower-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      16. lower-sqrt.f6479.4

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot 0.5\right)\right) \]
    5. Applied rewrites79.4%

      \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\sqrt{2} \cdot 0.5\right)\right)} \]
    6. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      2. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      4. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot \frac{1}{2}\right)\right) \]
      5. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      6. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)} \]
      7. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      8. pow1/2N/A

        \[\leadsto im \cdot \left(\color{blue}{{\left(\frac{1}{re}\right)}^{\frac{1}{2}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      9. sqr-powN/A

        \[\leadsto im \cdot \left(\color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot {\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      10. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      12. lift-/.f64N/A

        \[\leadsto im \cdot \left({\color{blue}{\left(\frac{1}{re}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      13. inv-powN/A

        \[\leadsto im \cdot \left({\color{blue}{\left({re}^{-1}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      14. pow-powN/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      15. lower-pow.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      16. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\left(-1 \cdot \color{blue}{\frac{1}{4}}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      17. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\color{blue}{\frac{-1}{4}}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      18. lift-*.f64N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right)\right)\right) \]
      19. associate-*r*N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \frac{1}{2}\right)}\right)\right) \]
    7. Applied rewrites79.6%

      \[\leadsto im \cdot \color{blue}{\left({re}^{-0.25} \cdot \left({re}^{-0.25} \cdot 0.5\right)\right)} \]
    8. Taylor expanded in im around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(im \cdot \sqrt{\frac{1}{re}}\right)} \]
    9. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(im \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot im\right)} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      4. lower-*.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      5. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      6. lower-/.f64N/A

        \[\leadsto \sqrt{\color{blue}{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      7. lower-*.f6480.0

        \[\leadsto \sqrt{\frac{1}{re}} \cdot \color{blue}{\left(im \cdot 0.5\right)} \]
    10. Applied rewrites80.0%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 4: 76.9% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.8e+112)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re 6.4e-24)
     (* 0.5 (sqrt (* 2.0 (- im re))))
     (* (sqrt (/ 1.0 re)) (* im 0.5)))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= 6.4e-24) {
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	} else {
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-1.8d+112)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else if (re <= 6.4d-24) then
        tmp = 0.5d0 * sqrt((2.0d0 * (im - re)))
    else
        tmp = sqrt((1.0d0 / re)) * (im * 0.5d0)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else if (re <= 6.4e-24) {
		tmp = 0.5 * Math.sqrt((2.0 * (im - re)));
	} else {
		tmp = Math.sqrt((1.0 / re)) * (im * 0.5);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.8e+112:
		tmp = 0.5 * math.sqrt((re * -4.0))
	elif re <= 6.4e-24:
		tmp = 0.5 * math.sqrt((2.0 * (im - re)))
	else:
		tmp = math.sqrt((1.0 / re)) * (im * 0.5)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.8e+112)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= 6.4e-24)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im - re))));
	else
		tmp = Float64(sqrt(Float64(1.0 / re)) * Float64(im * 0.5));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.8e+112)
		tmp = 0.5 * sqrt((re * -4.0));
	elseif (re <= 6.4e-24)
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	else
		tmp = sqrt((1.0 / re)) * (im * 0.5);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.8e+112], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 6.4e-24], N[(0.5 * N[Sqrt[N[(2.0 * N[(im - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision] * N[(im * 0.5), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -1.8e112

    1. Initial program 21.5%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -inf

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-4 \cdot re}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6481.9

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Applied rewrites81.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]

    if -1.8e112 < re < 6.40000000000000025e-24

    1. Initial program 53.8%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + -1 \cdot re\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im + \color{blue}{\left(\mathsf{neg}\left(re\right)\right)}\right)} \]
      2. unsub-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      3. lower--.f6477.8

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Applied rewrites77.8%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]

    if 6.40000000000000025e-24 < re

    1. Initial program 9.7%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. associate-*l*N/A

        \[\leadsto \color{blue}{\left(im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \sqrt{\frac{1}{re}}\right)\right)} \cdot \frac{1}{2} \]
      3. *-commutativeN/A

        \[\leadsto \left(im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)}\right) \cdot \frac{1}{2} \]
      4. associate-*r*N/A

        \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      5. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      6. lower-*.f64N/A

        \[\leadsto \color{blue}{im \cdot \left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      8. associate-*r*N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{2}\right)} \cdot \frac{1}{2}\right) \]
      9. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      10. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      12. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      13. lower-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      14. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      15. lower-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      16. lower-sqrt.f6479.4

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot 0.5\right)\right) \]
    5. Applied rewrites79.4%

      \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\sqrt{2} \cdot 0.5\right)\right)} \]
    6. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      2. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      4. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot \frac{1}{2}\right)\right) \]
      5. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      6. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)} \]
      7. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      8. pow1/2N/A

        \[\leadsto im \cdot \left(\color{blue}{{\left(\frac{1}{re}\right)}^{\frac{1}{2}}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      9. sqr-powN/A

        \[\leadsto im \cdot \left(\color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot {\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right) \]
      10. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right)} \]
      12. lift-/.f64N/A

        \[\leadsto im \cdot \left({\color{blue}{\left(\frac{1}{re}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      13. inv-powN/A

        \[\leadsto im \cdot \left({\color{blue}{\left({re}^{-1}\right)}}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      14. pow-powN/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      15. lower-pow.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{{re}^{\left(-1 \cdot \frac{\frac{1}{2}}{2}\right)}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      16. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\left(-1 \cdot \color{blue}{\frac{1}{4}}\right)} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      17. metadata-evalN/A

        \[\leadsto im \cdot \left({re}^{\color{blue}{\frac{-1}{4}}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)\right)\right) \]
      18. lift-*.f64N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \left(\sqrt{\frac{1}{2}} \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right)\right)\right) \]
      19. associate-*r*N/A

        \[\leadsto im \cdot \left({re}^{\frac{-1}{4}} \cdot \left({\left(\frac{1}{re}\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \frac{1}{2}\right)}\right)\right) \]
    7. Applied rewrites79.6%

      \[\leadsto im \cdot \color{blue}{\left({re}^{-0.25} \cdot \left({re}^{-0.25} \cdot 0.5\right)\right)} \]
    8. Taylor expanded in im around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(im \cdot \sqrt{\frac{1}{re}}\right)} \]
    9. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(im \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot im\right)} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      4. lower-*.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot \frac{1}{2}\right)} \]
      5. lower-sqrt.f64N/A

        \[\leadsto \color{blue}{\sqrt{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      6. lower-/.f64N/A

        \[\leadsto \sqrt{\color{blue}{\frac{1}{re}}} \cdot \left(im \cdot \frac{1}{2}\right) \]
      7. lower-*.f6480.0

        \[\leadsto \sqrt{\frac{1}{re}} \cdot \color{blue}{\left(im \cdot 0.5\right)} \]
    10. Applied rewrites80.0%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{re}} \cdot \left(im \cdot 0.5\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 5: 76.9% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{im \cdot 0.5}{\sqrt{re}}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.8e+112)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re 6.4e-24)
     (* 0.5 (sqrt (* 2.0 (- im re))))
     (/ (* im 0.5) (sqrt re)))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= 6.4e-24) {
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	} else {
		tmp = (im * 0.5) / sqrt(re);
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-1.8d+112)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else if (re <= 6.4d-24) then
        tmp = 0.5d0 * sqrt((2.0d0 * (im - re)))
    else
        tmp = (im * 0.5d0) / sqrt(re)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else if (re <= 6.4e-24) {
		tmp = 0.5 * Math.sqrt((2.0 * (im - re)));
	} else {
		tmp = (im * 0.5) / Math.sqrt(re);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.8e+112:
		tmp = 0.5 * math.sqrt((re * -4.0))
	elif re <= 6.4e-24:
		tmp = 0.5 * math.sqrt((2.0 * (im - re)))
	else:
		tmp = (im * 0.5) / math.sqrt(re)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.8e+112)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= 6.4e-24)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im - re))));
	else
		tmp = Float64(Float64(im * 0.5) / sqrt(re));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.8e+112)
		tmp = 0.5 * sqrt((re * -4.0));
	elseif (re <= 6.4e-24)
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	else
		tmp = (im * 0.5) / sqrt(re);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.8e+112], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 6.4e-24], N[(0.5 * N[Sqrt[N[(2.0 * N[(im - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(im * 0.5), $MachinePrecision] / N[Sqrt[re], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{im \cdot 0.5}{\sqrt{re}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -1.8e112

    1. Initial program 21.5%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -inf

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-4 \cdot re}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6481.9

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Applied rewrites81.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]

    if -1.8e112 < re < 6.40000000000000025e-24

    1. Initial program 53.8%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + -1 \cdot re\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im + \color{blue}{\left(\mathsf{neg}\left(re\right)\right)}\right)} \]
      2. unsub-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      3. lower--.f6477.8

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Applied rewrites77.8%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]

    if 6.40000000000000025e-24 < re

    1. Initial program 9.7%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. associate-*l*N/A

        \[\leadsto \color{blue}{\left(im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \sqrt{\frac{1}{re}}\right)\right)} \cdot \frac{1}{2} \]
      3. *-commutativeN/A

        \[\leadsto \left(im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)}\right) \cdot \frac{1}{2} \]
      4. associate-*r*N/A

        \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      5. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      6. lower-*.f64N/A

        \[\leadsto \color{blue}{im \cdot \left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      8. associate-*r*N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{2}\right)} \cdot \frac{1}{2}\right) \]
      9. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      10. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      12. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      13. lower-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      14. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      15. lower-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      16. lower-sqrt.f6479.4

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot 0.5\right)\right) \]
    5. Applied rewrites79.4%

      \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\sqrt{2} \cdot 0.5\right)\right)} \]
    6. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      2. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      4. lift-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      5. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot \frac{1}{2}\right)\right) \]
      6. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{2} \cdot \frac{1}{2}\right) \cdot \left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)\right)} \]
      8. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{2} \cdot \frac{1}{2}\right) \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)}\right) \]
      9. *-commutativeN/A

        \[\leadsto im \cdot \left(\left(\sqrt{2} \cdot \frac{1}{2}\right) \cdot \color{blue}{\left(\sqrt{\frac{1}{2}} \cdot \sqrt{\frac{1}{re}}\right)}\right) \]
      10. associate-*r*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\left(\sqrt{2} \cdot \frac{1}{2}\right) \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
      11. *-commutativeN/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \cdot \sqrt{\frac{1}{re}}\right) \]
      12. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \cdot \color{blue}{\sqrt{\frac{1}{re}}}\right) \]
      13. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \cdot \sqrt{\color{blue}{\frac{1}{re}}}\right) \]
      14. sqrt-divN/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \cdot \color{blue}{\frac{\sqrt{1}}{\sqrt{re}}}\right) \]
      15. metadata-evalN/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \cdot \frac{\color{blue}{1}}{\sqrt{re}}\right) \]
      16. un-div-invN/A

        \[\leadsto im \cdot \color{blue}{\frac{\sqrt{\frac{1}{2}} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)}{\sqrt{re}}} \]
    7. Applied rewrites79.9%

      \[\leadsto \color{blue}{\frac{im \cdot 0.5}{\sqrt{re}}} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 6: 76.9% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;im \cdot \frac{0.5}{\sqrt{re}}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.8e+112)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re 6.4e-24)
     (* 0.5 (sqrt (* 2.0 (- im re))))
     (* im (/ 0.5 (sqrt re))))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= 6.4e-24) {
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	} else {
		tmp = im * (0.5 / sqrt(re));
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-1.8d+112)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else if (re <= 6.4d-24) then
        tmp = 0.5d0 * sqrt((2.0d0 * (im - re)))
    else
        tmp = im * (0.5d0 / sqrt(re))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+112) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else if (re <= 6.4e-24) {
		tmp = 0.5 * Math.sqrt((2.0 * (im - re)));
	} else {
		tmp = im * (0.5 / Math.sqrt(re));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.8e+112:
		tmp = 0.5 * math.sqrt((re * -4.0))
	elif re <= 6.4e-24:
		tmp = 0.5 * math.sqrt((2.0 * (im - re)))
	else:
		tmp = im * (0.5 / math.sqrt(re))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.8e+112)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= 6.4e-24)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im - re))));
	else
		tmp = Float64(im * Float64(0.5 / sqrt(re)));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.8e+112)
		tmp = 0.5 * sqrt((re * -4.0));
	elseif (re <= 6.4e-24)
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	else
		tmp = im * (0.5 / sqrt(re));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.8e+112], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 6.4e-24], N[(0.5 * N[Sqrt[N[(2.0 * N[(im - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(im * N[(0.5 / N[Sqrt[re], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\

\mathbf{else}:\\
\;\;\;\;im \cdot \frac{0.5}{\sqrt{re}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -1.8e112

    1. Initial program 21.5%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -inf

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-4 \cdot re}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6481.9

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Applied rewrites81.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]

    if -1.8e112 < re < 6.40000000000000025e-24

    1. Initial program 53.8%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + -1 \cdot re\right)}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im + \color{blue}{\left(\mathsf{neg}\left(re\right)\right)}\right)} \]
      2. unsub-negN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
      3. lower--.f6477.8

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Applied rewrites77.8%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]

    if 6.40000000000000025e-24 < re

    1. Initial program 9.7%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right)} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(im \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \sqrt{\frac{1}{re}}\right) \cdot \frac{1}{2}} \]
      2. associate-*l*N/A

        \[\leadsto \color{blue}{\left(im \cdot \left(\left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right) \cdot \sqrt{\frac{1}{re}}\right)\right)} \cdot \frac{1}{2} \]
      3. *-commutativeN/A

        \[\leadsto \left(im \cdot \color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)}\right) \cdot \frac{1}{2} \]
      4. associate-*r*N/A

        \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      5. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      6. lower-*.f64N/A

        \[\leadsto \color{blue}{im \cdot \left(\frac{1}{2} \cdot \left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right)\right)} \]
      7. *-commutativeN/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \left(\sqrt{\frac{1}{2}} \cdot \sqrt{2}\right)\right) \cdot \frac{1}{2}\right)} \]
      8. associate-*r*N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \sqrt{2}\right)} \cdot \frac{1}{2}\right) \]
      9. associate-*l*N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      10. lower-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      11. lower-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      12. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      13. lower-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      14. lower-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      15. lower-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      16. lower-sqrt.f6479.4

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot 0.5\right)\right) \]
    5. Applied rewrites79.4%

      \[\leadsto \color{blue}{im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{0.5}\right) \cdot \left(\sqrt{2} \cdot 0.5\right)\right)} \]
    6. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\color{blue}{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      2. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\color{blue}{\sqrt{\frac{1}{re}}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      3. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      4. lift-*.f64N/A

        \[\leadsto im \cdot \left(\color{blue}{\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right)} \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \]
      5. lift-sqrt.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\color{blue}{\sqrt{2}} \cdot \frac{1}{2}\right)\right) \]
      6. lift-*.f64N/A

        \[\leadsto im \cdot \left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \color{blue}{\left(\sqrt{2} \cdot \frac{1}{2}\right)}\right) \]
      7. lift-*.f64N/A

        \[\leadsto im \cdot \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right)} \]
      8. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(\sqrt{\frac{1}{re}} \cdot \sqrt{\frac{1}{2}}\right) \cdot \left(\sqrt{2} \cdot \frac{1}{2}\right)\right) \cdot im} \]
    7. Applied rewrites79.8%

      \[\leadsto \color{blue}{\frac{0.5}{\sqrt{re}} \cdot im} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification79.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+112}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 6.4 \cdot 10^{-24}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;im \cdot \frac{0.5}{\sqrt{re}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 63.6% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -3.5 \cdot 10^{+78}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -3.5e+78) (* 0.5 (sqrt (* re -4.0))) (* 0.5 (sqrt (* 2.0 im)))))
double code(double re, double im) {
	double tmp;
	if (re <= -3.5e+78) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else {
		tmp = 0.5 * sqrt((2.0 * im));
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-3.5d+78)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else
        tmp = 0.5d0 * sqrt((2.0d0 * im))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -3.5e+78) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else {
		tmp = 0.5 * Math.sqrt((2.0 * im));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -3.5e+78:
		tmp = 0.5 * math.sqrt((re * -4.0))
	else:
		tmp = 0.5 * math.sqrt((2.0 * im))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -3.5e+78)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	else
		tmp = Float64(0.5 * sqrt(Float64(2.0 * im)));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -3.5e+78)
		tmp = 0.5 * sqrt((re * -4.0));
	else
		tmp = 0.5 * sqrt((2.0 * im));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -3.5e+78], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(2.0 * im), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -3.5 \cdot 10^{+78}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < -3.5000000000000001e78

    1. Initial program 24.3%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -inf

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-4 \cdot re}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6479.2

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Applied rewrites79.2%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]

    if -3.5000000000000001e78 < re

    1. Initial program 40.1%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{2 \cdot im}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{im \cdot 2}} \]
      2. lower-*.f6460.6

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
    5. Applied rewrites60.6%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification63.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -3.5 \cdot 10^{+78}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 52.0% accurate, 2.2× speedup?

\[\begin{array}{l} \\ 0.5 \cdot \sqrt{2 \cdot im} \end{array} \]
(FPCore (re im) :precision binary64 (* 0.5 (sqrt (* 2.0 im))))
double code(double re, double im) {
	return 0.5 * sqrt((2.0 * im));
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    code = 0.5d0 * sqrt((2.0d0 * im))
end function
public static double code(double re, double im) {
	return 0.5 * Math.sqrt((2.0 * im));
}
def code(re, im):
	return 0.5 * math.sqrt((2.0 * im))
function code(re, im)
	return Float64(0.5 * sqrt(Float64(2.0 * im)))
end
function tmp = code(re, im)
	tmp = 0.5 * sqrt((2.0 * im));
end
code[re_, im_] := N[(0.5 * N[Sqrt[N[(2.0 * im), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
0.5 \cdot \sqrt{2 \cdot im}
\end{array}
Derivation
  1. Initial program 37.5%

    \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
  2. Add Preprocessing
  3. Taylor expanded in re around 0

    \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{2 \cdot im}} \]
  4. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{im \cdot 2}} \]
    2. lower-*.f6454.3

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
  5. Applied rewrites54.3%

    \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
  6. Final simplification54.3%

    \[\leadsto 0.5 \cdot \sqrt{2 \cdot im} \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024219 
(FPCore (re im)
  :name "math.sqrt on complex, imaginary part, im greater than 0 branch"
  :precision binary64
  :pre (> im 0.0)
  (* 0.5 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))