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

Percentage Accurate: 41.0% → 90.1%
Time: 9.9s
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: 41.0% 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: 90.1% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \leq 0:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\mathsf{hypot}\left(re, im\right) - re\right)}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re))) 0.0)
   (* (* im 0.5) (sqrt (/ 1.0 re)))
   (* 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 = (im * 0.5) * sqrt((1.0 / re));
	} 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 = (im * 0.5) * Math.sqrt((1.0 / re));
	} 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 = (im * 0.5) * math.sqrt((1.0 / re))
	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(Float64(im * 0.5) * sqrt(Float64(1.0 / re)));
	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 = (im * 0.5) * sqrt((1.0 / re));
	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[(im * 0.5), $MachinePrecision] * N[Sqrt[N[(1.0 / re), $MachinePrecision]], $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:\\
\;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\

\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 9.4%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
      2. unpow2N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
      3. lower-*.f6439.9

        \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
    5. Simplified39.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{im \cdot im}{re}}} \]
    6. Taylor expanded in im around 0

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

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

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

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

        \[\leadsto \left(\frac{1}{2} \cdot im\right) \cdot \color{blue}{\sqrt{\frac{1}{re}}} \]
      5. lower-/.f6499.6

        \[\leadsto \left(0.5 \cdot im\right) \cdot \sqrt{\color{blue}{\frac{1}{re}}} \]
    8. Simplified99.6%

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

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

    1. Initial program 51.3%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lower-hypot.f6495.0

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\mathsf{hypot}\left(re, im\right)} - re\right)} \]
    4. Applied egg-rr95.0%

      \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\mathsf{hypot}\left(re, im\right)} - re\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification95.5%

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

Alternative 2: 81.4% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}\\ \mathbf{if}\;re \leq -5.2 \cdot 10^{+92}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq -1.42 \cdot 10^{-143}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(t\_0 - re\right)}\\ \mathbf{elif}\;re \leq 1.22 \cdot 10^{-60}:\\ \;\;\;\;0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, 2 \cdot im\right)}\\ \mathbf{elif}\;re \leq 8 \cdot 10^{+127}:\\ \;\;\;\;0.5 \cdot \frac{im \cdot \sqrt{2}}{\sqrt{re + t\_0}}\\ \mathbf{else}:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (let* ((t_0 (sqrt (fma re re (* im im)))))
   (if (<= re -5.2e+92)
     (* 0.5 (sqrt (* re -4.0)))
     (if (<= re -1.42e-143)
       (* 0.5 (sqrt (* 2.0 (- t_0 re))))
       (if (<= re 1.22e-60)
         (* 0.5 (sqrt (fma re (+ -2.0 (/ re im)) (* 2.0 im))))
         (if (<= re 8e+127)
           (* 0.5 (/ (* im (sqrt 2.0)) (sqrt (+ re t_0))))
           (* (* im 0.5) (sqrt (/ 1.0 re)))))))))
double code(double re, double im) {
	double t_0 = sqrt(fma(re, re, (im * im)));
	double tmp;
	if (re <= -5.2e+92) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= -1.42e-143) {
		tmp = 0.5 * sqrt((2.0 * (t_0 - re)));
	} else if (re <= 1.22e-60) {
		tmp = 0.5 * sqrt(fma(re, (-2.0 + (re / im)), (2.0 * im)));
	} else if (re <= 8e+127) {
		tmp = 0.5 * ((im * sqrt(2.0)) / sqrt((re + t_0)));
	} else {
		tmp = (im * 0.5) * sqrt((1.0 / re));
	}
	return tmp;
}
function code(re, im)
	t_0 = sqrt(fma(re, re, Float64(im * im)))
	tmp = 0.0
	if (re <= -5.2e+92)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= -1.42e-143)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(t_0 - re))));
	elseif (re <= 1.22e-60)
		tmp = Float64(0.5 * sqrt(fma(re, Float64(-2.0 + Float64(re / im)), Float64(2.0 * im))));
	elseif (re <= 8e+127)
		tmp = Float64(0.5 * Float64(Float64(im * sqrt(2.0)) / sqrt(Float64(re + t_0))));
	else
		tmp = Float64(Float64(im * 0.5) * sqrt(Float64(1.0 / re)));
	end
	return tmp
end
code[re_, im_] := Block[{t$95$0 = N[Sqrt[N[(re * re + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[re, -5.2e+92], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, -1.42e-143], N[(0.5 * N[Sqrt[N[(2.0 * N[(t$95$0 - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 1.22e-60], N[(0.5 * N[Sqrt[N[(re * N[(-2.0 + N[(re / im), $MachinePrecision]), $MachinePrecision] + N[(2.0 * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 8e+127], N[(0.5 * N[(N[(im * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] / N[Sqrt[N[(re + t$95$0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(im * 0.5), $MachinePrecision] * N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}\\
\mathbf{if}\;re \leq -5.2 \cdot 10^{+92}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq -1.42 \cdot 10^{-143}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(t\_0 - re\right)}\\

\mathbf{elif}\;re \leq 1.22 \cdot 10^{-60}:\\
\;\;\;\;0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, 2 \cdot im\right)}\\

\mathbf{elif}\;re \leq 8 \cdot 10^{+127}:\\
\;\;\;\;0.5 \cdot \frac{im \cdot \sqrt{2}}{\sqrt{re + t\_0}}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 5 regimes
  2. if re < -5.1999999999999998e92

    1. Initial program 28.1%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -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-*.f6485.6

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Simplified85.6%

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

    if -5.1999999999999998e92 < re < -1.42e-143

    1. Initial program 81.1%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    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-*.f6481.1

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \cdot 0.5} \]
    4. Applied egg-rr81.1%

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

    if -1.42e-143 < re < 1.22e-60

    1. Initial program 54.3%

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{fma}\left(re, \color{blue}{\frac{re}{im} + \left(\mathsf{neg}\left(2\right)\right)}, 2 \cdot im\right)} \]
      4. metadata-evalN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, \color{blue}{im \cdot 2}\right)} \]
      9. lower-*.f6490.8

        \[\leadsto 0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, \color{blue}{im \cdot 2}\right)} \]
    5. Simplified90.8%

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

    if 1.22e-60 < re < 7.99999999999999964e127

    1. Initial program 32.6%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lower-hypot.f6461.0

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\mathsf{hypot}\left(re, im\right)} - re\right)} \]
    4. Applied egg-rr61.0%

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(\mathsf{hypot}\left(re, im\right) - re\right)} \cdot 2} \]
      5. flip--N/A

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

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

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\frac{\sqrt{\left(\mathsf{hypot}\left(re, im\right) \cdot \mathsf{hypot}\left(re, im\right) - re \cdot re\right) \cdot 2}}{\sqrt{\mathsf{hypot}\left(re, im\right) + re}}} \]
    6. Applied egg-rr29.8%

      \[\leadsto 0.5 \cdot \color{blue}{\frac{\sqrt{\mathsf{fma}\left(re, re, \left(im + re\right) \cdot \left(im - re\right)\right) \cdot 2}}{\sqrt{re + \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}}}} \]
    7. Taylor expanded in re around 0

      \[\leadsto \frac{1}{2} \cdot \frac{\color{blue}{im \cdot \sqrt{2}}}{\sqrt{re + \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}}} \]
    8. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \frac{1}{2} \cdot \frac{\color{blue}{im \cdot \sqrt{2}}}{\sqrt{re + \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}}} \]
      2. lower-sqrt.f6470.5

        \[\leadsto 0.5 \cdot \frac{im \cdot \color{blue}{\sqrt{2}}}{\sqrt{re + \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}}} \]
    9. Simplified70.5%

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

    if 7.99999999999999964e127 < re

    1. Initial program 6.4%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
      2. unpow2N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
      3. lower-*.f6454.7

        \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
    5. Simplified54.7%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{im \cdot im}{re}}} \]
    6. Taylor expanded in im around 0

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

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

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

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

        \[\leadsto \left(\frac{1}{2} \cdot im\right) \cdot \color{blue}{\sqrt{\frac{1}{re}}} \]
      5. lower-/.f6492.9

        \[\leadsto \left(0.5 \cdot im\right) \cdot \sqrt{\color{blue}{\frac{1}{re}}} \]
    8. Simplified92.9%

      \[\leadsto \color{blue}{\left(0.5 \cdot im\right) \cdot \sqrt{\frac{1}{re}}} \]
  3. Recombined 5 regimes into one program.
  4. Final simplification84.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -5.2 \cdot 10^{+92}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq -1.42 \cdot 10^{-143}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\ \mathbf{elif}\;re \leq 1.22 \cdot 10^{-60}:\\ \;\;\;\;0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, 2 \cdot im\right)}\\ \mathbf{elif}\;re \leq 8 \cdot 10^{+127}:\\ \;\;\;\;0.5 \cdot \frac{im \cdot \sqrt{2}}{\sqrt{re + \sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)}}}\\ \mathbf{else}:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 77.8% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -5.2 \cdot 10^{+92}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq -1.42 \cdot 10^{-143}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\ \mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\ \;\;\;\;0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, 2 \cdot im\right)}\\ \mathbf{else}:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -5.2e+92)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re -1.42e-143)
     (* 0.5 (sqrt (* 2.0 (- (sqrt (fma re re (* im im))) re))))
     (if (<= re 9e+109)
       (* 0.5 (sqrt (fma re (+ -2.0 (/ re im)) (* 2.0 im))))
       (* (* im 0.5) (sqrt (/ 1.0 re)))))))
double code(double re, double im) {
	double tmp;
	if (re <= -5.2e+92) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= -1.42e-143) {
		tmp = 0.5 * sqrt((2.0 * (sqrt(fma(re, re, (im * im))) - re)));
	} else if (re <= 9e+109) {
		tmp = 0.5 * sqrt(fma(re, (-2.0 + (re / im)), (2.0 * im)));
	} else {
		tmp = (im * 0.5) * sqrt((1.0 / re));
	}
	return tmp;
}
function code(re, im)
	tmp = 0.0
	if (re <= -5.2e+92)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= -1.42e-143)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(fma(re, re, Float64(im * im))) - re))));
	elseif (re <= 9e+109)
		tmp = Float64(0.5 * sqrt(fma(re, Float64(-2.0 + Float64(re / im)), Float64(2.0 * im))));
	else
		tmp = Float64(Float64(im * 0.5) * sqrt(Float64(1.0 / re)));
	end
	return tmp
end
code[re_, im_] := If[LessEqual[re, -5.2e+92], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, -1.42e-143], 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], If[LessEqual[re, 9e+109], N[(0.5 * N[Sqrt[N[(re * N[(-2.0 + N[(re / im), $MachinePrecision]), $MachinePrecision] + N[(2.0 * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(im * 0.5), $MachinePrecision] * N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -5.2 \cdot 10^{+92}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq -1.42 \cdot 10^{-143}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\

\mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\
\;\;\;\;0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, 2 \cdot im\right)}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 4 regimes
  2. if re < -5.1999999999999998e92

    1. Initial program 28.1%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around -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-*.f6485.6

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Simplified85.6%

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

    if -5.1999999999999998e92 < re < -1.42e-143

    1. Initial program 81.1%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    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-*.f6481.1

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \cdot 0.5} \]
    4. Applied egg-rr81.1%

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

    if -1.42e-143 < re < 8.9999999999999992e109

    1. Initial program 47.2%

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{fma}\left(re, \color{blue}{\frac{re}{im} + \left(\mathsf{neg}\left(2\right)\right)}, 2 \cdot im\right)} \]
      4. metadata-evalN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, \color{blue}{im \cdot 2}\right)} \]
      9. lower-*.f6480.9

        \[\leadsto 0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, \color{blue}{im \cdot 2}\right)} \]
    5. Simplified80.9%

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

    if 8.9999999999999992e109 < 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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
      2. unpow2N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
      3. lower-*.f6449.9

        \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
    5. Simplified49.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{im \cdot im}{re}}} \]
    6. Taylor expanded in im around 0

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

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

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

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

        \[\leadsto \left(\frac{1}{2} \cdot im\right) \cdot \color{blue}{\sqrt{\frac{1}{re}}} \]
      5. lower-/.f6490.5

        \[\leadsto \left(0.5 \cdot im\right) \cdot \sqrt{\color{blue}{\frac{1}{re}}} \]
    8. Simplified90.5%

      \[\leadsto \color{blue}{\left(0.5 \cdot im\right) \cdot \sqrt{\frac{1}{re}}} \]
  3. Recombined 4 regimes into one program.
  4. Final simplification82.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -5.2 \cdot 10^{+92}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq -1.42 \cdot 10^{-143}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} - re\right)}\\ \mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\ \;\;\;\;0.5 \cdot \sqrt{\mathsf{fma}\left(re, -2 + \frac{re}{im}, 2 \cdot im\right)}\\ \mathbf{else}:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 74.6% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.85 \cdot 10^{+93}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.85e+93)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re 9e+109)
     (* 0.5 (sqrt (* 2.0 (- im re))))
     (* (* im 0.5) (sqrt (/ 1.0 re))))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.85e+93) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= 9e+109) {
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	} else {
		tmp = (im * 0.5) * sqrt((1.0 / re));
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-1.85d+93)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else if (re <= 9d+109) then
        tmp = 0.5d0 * sqrt((2.0d0 * (im - re)))
    else
        tmp = (im * 0.5d0) * sqrt((1.0d0 / re))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.85e+93) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else if (re <= 9e+109) {
		tmp = 0.5 * Math.sqrt((2.0 * (im - re)));
	} else {
		tmp = (im * 0.5) * Math.sqrt((1.0 / re));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.85e+93:
		tmp = 0.5 * math.sqrt((re * -4.0))
	elif re <= 9e+109:
		tmp = 0.5 * math.sqrt((2.0 * (im - re)))
	else:
		tmp = (im * 0.5) * math.sqrt((1.0 / re))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.85e+93)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= 9e+109)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im - re))));
	else
		tmp = Float64(Float64(im * 0.5) * sqrt(Float64(1.0 / re)));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.85e+93)
		tmp = 0.5 * sqrt((re * -4.0));
	elseif (re <= 9e+109)
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	else
		tmp = (im * 0.5) * sqrt((1.0 / re));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.85e+93], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 9e+109], N[(0.5 * N[Sqrt[N[(2.0 * N[(im - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(im * 0.5), $MachinePrecision] * N[Sqrt[N[(1.0 / re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.85 \cdot 10^{+93}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -1.84999999999999994e93

    1. Initial program 28.7%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6487.4

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Simplified87.4%

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

    if -1.84999999999999994e93 < re < 8.9999999999999992e109

    1. Initial program 57.3%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 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--.f6474.5

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Simplified74.5%

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

    if 8.9999999999999992e109 < 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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
      2. unpow2N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
      3. lower-*.f6449.9

        \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
    5. Simplified49.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{im \cdot im}{re}}} \]
    6. Taylor expanded in im around 0

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

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

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

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

        \[\leadsto \left(\frac{1}{2} \cdot im\right) \cdot \color{blue}{\sqrt{\frac{1}{re}}} \]
      5. lower-/.f6490.5

        \[\leadsto \left(0.5 \cdot im\right) \cdot \sqrt{\color{blue}{\frac{1}{re}}} \]
    8. Simplified90.5%

      \[\leadsto \color{blue}{\left(0.5 \cdot im\right) \cdot \sqrt{\frac{1}{re}}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification78.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -1.85 \cdot 10^{+93}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;\left(im \cdot 0.5\right) \cdot \sqrt{\frac{1}{re}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 74.6% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.85 \cdot 10^{+93}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \mathbf{else}:\\ \;\;\;\;im \cdot \frac{0.5}{\sqrt{re}}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.85e+93)
   (* 0.5 (sqrt (* re -4.0)))
   (if (<= re 9e+109)
     (* 0.5 (sqrt (* 2.0 (- im re))))
     (* im (/ 0.5 (sqrt re))))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.85e+93) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else if (re <= 9e+109) {
		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 <= (-1.85d+93)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else if (re <= 9d+109) 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 <= -1.85e+93) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else if (re <= 9e+109) {
		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 <= -1.85e+93:
		tmp = 0.5 * math.sqrt((re * -4.0))
	elif re <= 9e+109:
		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 <= -1.85e+93)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	elseif (re <= 9e+109)
		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 <= -1.85e+93)
		tmp = 0.5 * sqrt((re * -4.0));
	elseif (re <= 9e+109)
		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, -1.85e+93], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 9e+109], 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 -1.85 \cdot 10^{+93}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

\mathbf{elif}\;re \leq 9 \cdot 10^{+109}:\\
\;\;\;\;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 < -1.84999999999999994e93

    1. Initial program 28.7%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6487.4

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Simplified87.4%

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

    if -1.84999999999999994e93 < re < 8.9999999999999992e109

    1. Initial program 57.3%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in re around 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--.f6474.5

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Simplified74.5%

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

    if 8.9999999999999992e109 < 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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\frac{{im}^{2}}{re}}} \]
      2. unpow2N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
      3. lower-*.f6449.9

        \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{im \cdot im}}{re}} \]
    5. Simplified49.9%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{im \cdot im}{re}}} \]
    6. Taylor expanded in im around 0

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

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

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

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

        \[\leadsto \left(\frac{1}{2} \cdot im\right) \cdot \color{blue}{\sqrt{\frac{1}{re}}} \]
      5. lower-/.f6490.5

        \[\leadsto \left(0.5 \cdot im\right) \cdot \sqrt{\color{blue}{\frac{1}{re}}} \]
    8. Simplified90.5%

      \[\leadsto \color{blue}{\left(0.5 \cdot im\right) \cdot \sqrt{\frac{1}{re}}} \]
    9. Step-by-step derivation
      1. *-commutativeN/A

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

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

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

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

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

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

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

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

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

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

        \[\leadsto im \cdot \color{blue}{\frac{\frac{1}{2}}{\sqrt{re}}} \]
      12. lower-sqrt.f6490.3

        \[\leadsto im \cdot \frac{0.5}{\color{blue}{\sqrt{re}}} \]
    10. Applied egg-rr90.3%

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

Alternative 6: 63.3% accurate, 1.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.85 \cdot 10^{+93}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.85e+93)
   (* 0.5 (sqrt (* re -4.0)))
   (* 0.5 (sqrt (* 2.0 (- im re))))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.85e+93) {
		tmp = 0.5 * sqrt((re * -4.0));
	} else {
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-1.85d+93)) then
        tmp = 0.5d0 * sqrt((re * (-4.0d0)))
    else
        tmp = 0.5d0 * sqrt((2.0d0 * (im - re)))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.85e+93) {
		tmp = 0.5 * Math.sqrt((re * -4.0));
	} else {
		tmp = 0.5 * Math.sqrt((2.0 * (im - re)));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.85e+93:
		tmp = 0.5 * math.sqrt((re * -4.0))
	else:
		tmp = 0.5 * math.sqrt((2.0 * (im - re)))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.85e+93)
		tmp = Float64(0.5 * sqrt(Float64(re * -4.0)));
	else
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im - re))));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.85e+93)
		tmp = 0.5 * sqrt((re * -4.0));
	else
		tmp = 0.5 * sqrt((2.0 * (im - re)));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.85e+93], N[(0.5 * N[Sqrt[N[(re * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(2.0 * N[(im - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.85 \cdot 10^{+93}:\\
\;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < -1.84999999999999994e93

    1. Initial program 28.7%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{re \cdot -4}} \]
      2. lower-*.f6487.4

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{re \cdot -4}} \]
    5. Simplified87.4%

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

    if -1.84999999999999994e93 < re

    1. Initial program 50.8%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
    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--.f6465.8

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im - re\right)}} \]
    5. Simplified65.8%

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

Alternative 7: 64.5% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+36}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.8e+36) (* 0.5 (sqrt (* re -4.0))) (* 0.5 (sqrt (* 2.0 im)))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.8e+36) {
		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 <= (-1.8d+36)) 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 <= -1.8e+36) {
		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 <= -1.8e+36:
		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 <= -1.8e+36)
		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 <= -1.8e+36)
		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, -1.8e+36], 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 -1.8 \cdot 10^{+36}:\\
\;\;\;\;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 < -1.7999999999999999e36

    1. Initial program 37.7%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-4 \cdot re}} \]
    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. Simplified79.2%

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

    if -1.7999999999999999e36 < re

    1. Initial program 49.8%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{im \cdot 2}} \]
      2. lower-*.f6465.8

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
    5. Simplified65.8%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification68.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -1.8 \cdot 10^{+36}:\\ \;\;\;\;0.5 \cdot \sqrt{re \cdot -4}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 51.8% 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 47.1%

    \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)} \]
  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-*.f6457.0

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
  5. Simplified57.0%

    \[\leadsto 0.5 \cdot \sqrt{\color{blue}{im \cdot 2}} \]
  6. Final simplification57.0%

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

Reproduce

?
herbie shell --seed 2024208 
(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)))))