math.sqrt on complex, real part

Percentage Accurate: 41.3% → 82.6%
Time: 8.4s
Alternatives: 9
Speedup: 1.7×

Specification

?
\[\begin{array}{l} \\ 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \end{array} \]
(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 9 alternatives:

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

Initial Program: 41.3% 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: 82.6% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -3.8 \cdot 10^{+100}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2} \cdot \left(\sqrt{\mathsf{hypot}\left(im, re\right) + re} \cdot 0.5\right)\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -3.8e+100)
   (* (sqrt (* (/ (- im) re) im)) 0.5)
   (* (sqrt 2.0) (* (sqrt (+ (hypot im re) re)) 0.5))))
double code(double re, double im) {
	double tmp;
	if (re <= -3.8e+100) {
		tmp = sqrt(((-im / re) * im)) * 0.5;
	} else {
		tmp = sqrt(2.0) * (sqrt((hypot(im, re) + re)) * 0.5);
	}
	return tmp;
}
public static double code(double re, double im) {
	double tmp;
	if (re <= -3.8e+100) {
		tmp = Math.sqrt(((-im / re) * im)) * 0.5;
	} else {
		tmp = Math.sqrt(2.0) * (Math.sqrt((Math.hypot(im, re) + re)) * 0.5);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -3.8e+100:
		tmp = math.sqrt(((-im / re) * im)) * 0.5
	else:
		tmp = math.sqrt(2.0) * (math.sqrt((math.hypot(im, re) + re)) * 0.5)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -3.8e+100)
		tmp = Float64(sqrt(Float64(Float64(Float64(-im) / re) * im)) * 0.5);
	else
		tmp = Float64(sqrt(2.0) * Float64(sqrt(Float64(hypot(im, re) + re)) * 0.5));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -3.8e+100)
		tmp = sqrt(((-im / re) * im)) * 0.5;
	else
		tmp = sqrt(2.0) * (sqrt((hypot(im, re) + re)) * 0.5);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -3.8e+100], N[(N[Sqrt[N[(N[((-im) / re), $MachinePrecision] * im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[(N[Sqrt[2.0], $MachinePrecision] * N[(N[Sqrt[N[(N[Sqrt[im ^ 2 + re ^ 2], $MachinePrecision] + re), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -3.8 \cdot 10^{+100}:\\
\;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < -3.79999999999999963e100

    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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)}} \]
      2. unpow2N/A

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\color{blue}{im \cdot \frac{im}{re}}\right)} \]
      4. distribute-lft-neg-inN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(-im\right)} \cdot \frac{im}{re}} \]
      9. lower-/.f6477.0

        \[\leadsto 0.5 \cdot \sqrt{\left(-im\right) \cdot \color{blue}{\frac{im}{re}}} \]
    5. Applied rewrites77.0%

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

    if -3.79999999999999963e100 < re

    1. Initial program 48.5%

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

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

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

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

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

        \[\leadsto {\color{blue}{\left(2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)\right)}}^{\frac{1}{2}} \cdot \frac{1}{2} \]
      6. unpow-prod-downN/A

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

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

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

        \[\leadsto \color{blue}{\left({\left(\sqrt{re \cdot re + im \cdot im} + re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right) \cdot {2}^{\frac{1}{2}}} \]
    4. Applied rewrites90.8%

      \[\leadsto \color{blue}{\left(\sqrt{\mathsf{hypot}\left(im, re\right) + re} \cdot 0.5\right) \cdot \sqrt{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification88.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -3.8 \cdot 10^{+100}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2} \cdot \left(\sqrt{\mathsf{hypot}\left(im, re\right) + re} \cdot 0.5\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 83.1% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -3.8 \cdot 10^{+100}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\left(\mathsf{hypot}\left(im, re\right) + re\right) \cdot 2} \cdot 0.5\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -3.8e+100)
   (* (sqrt (* (/ (- im) re) im)) 0.5)
   (* (sqrt (* (+ (hypot im re) re) 2.0)) 0.5)))
double code(double re, double im) {
	double tmp;
	if (re <= -3.8e+100) {
		tmp = sqrt(((-im / re) * im)) * 0.5;
	} else {
		tmp = sqrt(((hypot(im, re) + re) * 2.0)) * 0.5;
	}
	return tmp;
}
public static double code(double re, double im) {
	double tmp;
	if (re <= -3.8e+100) {
		tmp = Math.sqrt(((-im / re) * im)) * 0.5;
	} else {
		tmp = Math.sqrt(((Math.hypot(im, re) + re) * 2.0)) * 0.5;
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -3.8e+100:
		tmp = math.sqrt(((-im / re) * im)) * 0.5
	else:
		tmp = math.sqrt(((math.hypot(im, re) + re) * 2.0)) * 0.5
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -3.8e+100)
		tmp = Float64(sqrt(Float64(Float64(Float64(-im) / re) * im)) * 0.5);
	else
		tmp = Float64(sqrt(Float64(Float64(hypot(im, re) + re) * 2.0)) * 0.5);
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -3.8e+100)
		tmp = sqrt(((-im / re) * im)) * 0.5;
	else
		tmp = sqrt(((hypot(im, re) + re) * 2.0)) * 0.5;
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -3.8e+100], N[(N[Sqrt[N[(N[((-im) / re), $MachinePrecision] * im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[(N[Sqrt[N[(N[(N[Sqrt[im ^ 2 + re ^ 2], $MachinePrecision] + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -3.8 \cdot 10^{+100}:\\
\;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < -3.79999999999999963e100

    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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)}} \]
      2. unpow2N/A

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\color{blue}{im \cdot \frac{im}{re}}\right)} \]
      4. distribute-lft-neg-inN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(-im\right)} \cdot \frac{im}{re}} \]
      9. lower-/.f6477.0

        \[\leadsto 0.5 \cdot \sqrt{\left(-im\right) \cdot \color{blue}{\frac{im}{re}}} \]
    5. Applied rewrites77.0%

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

    if -3.79999999999999963e100 < re

    1. Initial program 48.5%

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

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

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \cdot \frac{1}{2}} \]
      3. lower-*.f6448.5

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \cdot 0.5} \]
      4. lift-*.f64N/A

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

        \[\leadsto \sqrt{\color{blue}{\left(\sqrt{re \cdot re + im \cdot im} + re\right) \cdot 2}} \cdot \frac{1}{2} \]
      6. lower-*.f6448.5

        \[\leadsto \sqrt{\color{blue}{\left(\sqrt{re \cdot re + im \cdot im} + re\right) \cdot 2}} \cdot 0.5 \]
      7. lift-sqrt.f64N/A

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

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

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

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

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

        \[\leadsto \sqrt{\left(\color{blue}{\mathsf{hypot}\left(im, re\right)} + re\right) \cdot 2} \cdot 0.5 \]
    4. Applied rewrites90.1%

      \[\leadsto \color{blue}{\sqrt{\left(\mathsf{hypot}\left(im, re\right) + re\right) \cdot 2} \cdot 0.5} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification88.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -3.8 \cdot 10^{+100}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\left(\mathsf{hypot}\left(im, re\right) + re\right) \cdot 2} \cdot 0.5\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 56.1% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{elif}\;re \leq 1.55 \cdot 10^{-131}:\\ \;\;\;\;\left(\sqrt{im + re} \cdot 0.5\right) \cdot \sqrt{2}\\ \mathbf{elif}\;re \leq 10^{+125}:\\ \;\;\;\;\sqrt{\left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -2.45e+95)
   (* (sqrt (* (/ (- im) re) im)) 0.5)
   (if (<= re 1.55e-131)
     (* (* (sqrt (+ im re)) 0.5) (sqrt 2.0))
     (if (<= re 1e+125)
       (* (sqrt (* (+ (sqrt (fma re re (* im im))) re) 2.0)) 0.5)
       (sqrt re)))))
double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+95) {
		tmp = sqrt(((-im / re) * im)) * 0.5;
	} else if (re <= 1.55e-131) {
		tmp = (sqrt((im + re)) * 0.5) * sqrt(2.0);
	} else if (re <= 1e+125) {
		tmp = sqrt(((sqrt(fma(re, re, (im * im))) + re) * 2.0)) * 0.5;
	} else {
		tmp = sqrt(re);
	}
	return tmp;
}
function code(re, im)
	tmp = 0.0
	if (re <= -2.45e+95)
		tmp = Float64(sqrt(Float64(Float64(Float64(-im) / re) * im)) * 0.5);
	elseif (re <= 1.55e-131)
		tmp = Float64(Float64(sqrt(Float64(im + re)) * 0.5) * sqrt(2.0));
	elseif (re <= 1e+125)
		tmp = Float64(sqrt(Float64(Float64(sqrt(fma(re, re, Float64(im * im))) + re) * 2.0)) * 0.5);
	else
		tmp = sqrt(re);
	end
	return tmp
end
code[re_, im_] := If[LessEqual[re, -2.45e+95], N[(N[Sqrt[N[(N[((-im) / re), $MachinePrecision] * im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[re, 1.55e-131], N[(N[(N[Sqrt[N[(im + re), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 1e+125], N[(N[Sqrt[N[(N[(N[Sqrt[N[(re * re + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\
\;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\

\mathbf{elif}\;re \leq 1.55 \cdot 10^{-131}:\\
\;\;\;\;\left(\sqrt{im + re} \cdot 0.5\right) \cdot \sqrt{2}\\

\mathbf{elif}\;re \leq 10^{+125}:\\
\;\;\;\;\sqrt{\left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right) \cdot 2} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\sqrt{re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 4 regimes
  2. if re < -2.4499999999999999e95

    1. Initial program 5.6%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)}} \]
      2. unpow2N/A

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\color{blue}{im \cdot \frac{im}{re}}\right)} \]
      4. distribute-lft-neg-inN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(-im\right)} \cdot \frac{im}{re}} \]
      9. lower-/.f6475.4

        \[\leadsto 0.5 \cdot \sqrt{\left(-im\right) \cdot \color{blue}{\frac{im}{re}}} \]
    5. Applied rewrites75.4%

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

    if -2.4499999999999999e95 < re < 1.5500000000000001e-131

    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. Step-by-step derivation
      1. lift-*.f64N/A

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

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

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

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

        \[\leadsto {\color{blue}{\left(2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)\right)}}^{\frac{1}{2}} \cdot \frac{1}{2} \]
      6. unpow-prod-downN/A

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

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

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

        \[\leadsto \color{blue}{\left({\left(\sqrt{re \cdot re + im \cdot im} + re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right) \cdot {2}^{\frac{1}{2}}} \]
    4. Applied rewrites83.5%

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

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

        \[\leadsto \left(\sqrt{\color{blue}{re + im}} \cdot \frac{1}{2}\right) \cdot \sqrt{2} \]
      2. lower-+.f6442.6

        \[\leadsto \left(\sqrt{\color{blue}{re + im}} \cdot 0.5\right) \cdot \sqrt{2} \]
    7. Applied rewrites42.6%

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

    if 1.5500000000000001e-131 < re < 9.9999999999999992e124

    1. Initial program 84.0%

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{re \cdot re} + im \cdot im} + re\right)} \]
      3. lower-fma.f6484.0

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{\mathsf{fma}\left(re, re, im \cdot im\right)}} + re\right)} \]
    4. Applied rewrites84.0%

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

    if 9.9999999999999992e124 < re

    1. Initial program 13.8%

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

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
      2. unpow2N/A

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

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

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

        \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
      6. *-lft-identityN/A

        \[\leadsto \color{blue}{\sqrt{re}} \]
      7. lower-sqrt.f6482.0

        \[\leadsto \color{blue}{\sqrt{re}} \]
    5. Applied rewrites82.0%

      \[\leadsto \color{blue}{\sqrt{re}} \]
  3. Recombined 4 regimes into one program.
  4. Final simplification64.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{elif}\;re \leq 1.55 \cdot 10^{-131}:\\ \;\;\;\;\left(\sqrt{im + re} \cdot 0.5\right) \cdot \sqrt{2}\\ \mathbf{elif}\;re \leq 10^{+125}:\\ \;\;\;\;\sqrt{\left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 51.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{elif}\;re \leq 130000000:\\ \;\;\;\;\left(\sqrt{im + re} \cdot 0.5\right) \cdot \sqrt{2}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -2.45e+95)
   (* (sqrt (* (/ (- im) re) im)) 0.5)
   (if (<= re 130000000.0) (* (* (sqrt (+ im re)) 0.5) (sqrt 2.0)) (sqrt re))))
double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+95) {
		tmp = sqrt(((-im / re) * im)) * 0.5;
	} else if (re <= 130000000.0) {
		tmp = (sqrt((im + re)) * 0.5) * sqrt(2.0);
	} else {
		tmp = 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 <= (-2.45d+95)) then
        tmp = sqrt(((-im / re) * im)) * 0.5d0
    else if (re <= 130000000.0d0) then
        tmp = (sqrt((im + re)) * 0.5d0) * sqrt(2.0d0)
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+95) {
		tmp = Math.sqrt(((-im / re) * im)) * 0.5;
	} else if (re <= 130000000.0) {
		tmp = (Math.sqrt((im + re)) * 0.5) * Math.sqrt(2.0);
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -2.45e+95:
		tmp = math.sqrt(((-im / re) * im)) * 0.5
	elif re <= 130000000.0:
		tmp = (math.sqrt((im + re)) * 0.5) * math.sqrt(2.0)
	else:
		tmp = math.sqrt(re)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -2.45e+95)
		tmp = Float64(sqrt(Float64(Float64(Float64(-im) / re) * im)) * 0.5);
	elseif (re <= 130000000.0)
		tmp = Float64(Float64(sqrt(Float64(im + re)) * 0.5) * sqrt(2.0));
	else
		tmp = sqrt(re);
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -2.45e+95)
		tmp = sqrt(((-im / re) * im)) * 0.5;
	elseif (re <= 130000000.0)
		tmp = (sqrt((im + re)) * 0.5) * sqrt(2.0);
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -2.45e+95], N[(N[Sqrt[N[(N[((-im) / re), $MachinePrecision] * im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[re, 130000000.0], N[(N[(N[Sqrt[N[(im + re), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\
\;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\

\mathbf{elif}\;re \leq 130000000:\\
\;\;\;\;\left(\sqrt{im + re} \cdot 0.5\right) \cdot \sqrt{2}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -2.4499999999999999e95

    1. Initial program 5.6%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)}} \]
      2. unpow2N/A

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\color{blue}{im \cdot \frac{im}{re}}\right)} \]
      4. distribute-lft-neg-inN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(-im\right)} \cdot \frac{im}{re}} \]
      9. lower-/.f6475.4

        \[\leadsto 0.5 \cdot \sqrt{\left(-im\right) \cdot \color{blue}{\frac{im}{re}}} \]
    5. Applied rewrites75.4%

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

    if -2.4499999999999999e95 < re < 1.3e8

    1. Initial program 54.1%

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

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

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

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

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

        \[\leadsto {\color{blue}{\left(2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)\right)}}^{\frac{1}{2}} \cdot \frac{1}{2} \]
      6. unpow-prod-downN/A

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

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

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

        \[\leadsto \color{blue}{\left({\left(\sqrt{re \cdot re + im \cdot im} + re\right)}^{\frac{1}{2}} \cdot \frac{1}{2}\right) \cdot {2}^{\frac{1}{2}}} \]
    4. Applied rewrites86.5%

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

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

        \[\leadsto \left(\sqrt{\color{blue}{re + im}} \cdot \frac{1}{2}\right) \cdot \sqrt{2} \]
      2. lower-+.f6440.1

        \[\leadsto \left(\sqrt{\color{blue}{re + im}} \cdot 0.5\right) \cdot \sqrt{2} \]
    7. Applied rewrites40.1%

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

    if 1.3e8 < re

    1. Initial program 39.0%

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

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
      2. unpow2N/A

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

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

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

        \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
      6. *-lft-identityN/A

        \[\leadsto \color{blue}{\sqrt{re}} \]
      7. lower-sqrt.f6477.8

        \[\leadsto \color{blue}{\sqrt{re}} \]
    5. Applied rewrites77.8%

      \[\leadsto \color{blue}{\sqrt{re}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification57.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{elif}\;re \leq 130000000:\\ \;\;\;\;\left(\sqrt{im + re} \cdot 0.5\right) \cdot \sqrt{2}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 51.4% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{elif}\;re \leq 1.04 \cdot 10^{-120}:\\ \;\;\;\;\left(\sqrt{im} \cdot \sqrt{2}\right) \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -2.45e+95)
   (* (sqrt (* (/ (- im) re) im)) 0.5)
   (if (<= re 1.04e-120) (* (* (sqrt im) (sqrt 2.0)) 0.5) (sqrt re))))
double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+95) {
		tmp = sqrt(((-im / re) * im)) * 0.5;
	} else if (re <= 1.04e-120) {
		tmp = (sqrt(im) * sqrt(2.0)) * 0.5;
	} else {
		tmp = 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 <= (-2.45d+95)) then
        tmp = sqrt(((-im / re) * im)) * 0.5d0
    else if (re <= 1.04d-120) then
        tmp = (sqrt(im) * sqrt(2.0d0)) * 0.5d0
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+95) {
		tmp = Math.sqrt(((-im / re) * im)) * 0.5;
	} else if (re <= 1.04e-120) {
		tmp = (Math.sqrt(im) * Math.sqrt(2.0)) * 0.5;
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -2.45e+95:
		tmp = math.sqrt(((-im / re) * im)) * 0.5
	elif re <= 1.04e-120:
		tmp = (math.sqrt(im) * math.sqrt(2.0)) * 0.5
	else:
		tmp = math.sqrt(re)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -2.45e+95)
		tmp = Float64(sqrt(Float64(Float64(Float64(-im) / re) * im)) * 0.5);
	elseif (re <= 1.04e-120)
		tmp = Float64(Float64(sqrt(im) * sqrt(2.0)) * 0.5);
	else
		tmp = sqrt(re);
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -2.45e+95)
		tmp = sqrt(((-im / re) * im)) * 0.5;
	elseif (re <= 1.04e-120)
		tmp = (sqrt(im) * sqrt(2.0)) * 0.5;
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -2.45e+95], N[(N[Sqrt[N[(N[((-im) / re), $MachinePrecision] * im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[re, 1.04e-120], N[(N[(N[Sqrt[im], $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\
\;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\

\mathbf{elif}\;re \leq 1.04 \cdot 10^{-120}:\\
\;\;\;\;\left(\sqrt{im} \cdot \sqrt{2}\right) \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\sqrt{re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -2.4499999999999999e95

    1. Initial program 5.6%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)}} \]
      2. unpow2N/A

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\color{blue}{im \cdot \frac{im}{re}}\right)} \]
      4. distribute-lft-neg-inN/A

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{\left(-im\right)} \cdot \frac{im}{re}} \]
      9. lower-/.f6475.4

        \[\leadsto 0.5 \cdot \sqrt{\left(-im\right) \cdot \color{blue}{\frac{im}{re}}} \]
    5. Applied rewrites75.4%

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

    if -2.4499999999999999e95 < re < 1.03999999999999994e-120

    1. Initial program 47.7%

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \left(\color{blue}{\sqrt{2}} \cdot \sqrt{im}\right) \]
      4. lower-sqrt.f6441.8

        \[\leadsto 0.5 \cdot \left(\sqrt{2} \cdot \color{blue}{\sqrt{im}}\right) \]
    5. Applied rewrites41.8%

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

    if 1.03999999999999994e-120 < 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 inf

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
      2. unpow2N/A

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

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

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

        \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
      6. *-lft-identityN/A

        \[\leadsto \color{blue}{\sqrt{re}} \]
      7. lower-sqrt.f6471.8

        \[\leadsto \color{blue}{\sqrt{re}} \]
    5. Applied rewrites71.8%

      \[\leadsto \color{blue}{\sqrt{re}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification59.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+95}:\\ \;\;\;\;\sqrt{\frac{-im}{re} \cdot im} \cdot 0.5\\ \mathbf{elif}\;re \leq 1.04 \cdot 10^{-120}:\\ \;\;\;\;\left(\sqrt{im} \cdot \sqrt{2}\right) \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 44.5% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+188}:\\ \;\;\;\;\sqrt{\left(\left(-re\right) + re\right) \cdot 2} \cdot 0.5\\ \mathbf{elif}\;re \leq 1.04 \cdot 10^{-120}:\\ \;\;\;\;\left(\sqrt{im} \cdot \sqrt{2}\right) \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -2.45e+188)
   (* (sqrt (* (+ (- re) re) 2.0)) 0.5)
   (if (<= re 1.04e-120) (* (* (sqrt im) (sqrt 2.0)) 0.5) (sqrt re))))
double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+188) {
		tmp = sqrt(((-re + re) * 2.0)) * 0.5;
	} else if (re <= 1.04e-120) {
		tmp = (sqrt(im) * sqrt(2.0)) * 0.5;
	} else {
		tmp = 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 <= (-2.45d+188)) then
        tmp = sqrt(((-re + re) * 2.0d0)) * 0.5d0
    else if (re <= 1.04d-120) then
        tmp = (sqrt(im) * sqrt(2.0d0)) * 0.5d0
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -2.45e+188) {
		tmp = Math.sqrt(((-re + re) * 2.0)) * 0.5;
	} else if (re <= 1.04e-120) {
		tmp = (Math.sqrt(im) * Math.sqrt(2.0)) * 0.5;
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -2.45e+188:
		tmp = math.sqrt(((-re + re) * 2.0)) * 0.5
	elif re <= 1.04e-120:
		tmp = (math.sqrt(im) * math.sqrt(2.0)) * 0.5
	else:
		tmp = math.sqrt(re)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -2.45e+188)
		tmp = Float64(sqrt(Float64(Float64(Float64(-re) + re) * 2.0)) * 0.5);
	elseif (re <= 1.04e-120)
		tmp = Float64(Float64(sqrt(im) * sqrt(2.0)) * 0.5);
	else
		tmp = sqrt(re);
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -2.45e+188)
		tmp = sqrt(((-re + re) * 2.0)) * 0.5;
	elseif (re <= 1.04e-120)
		tmp = (sqrt(im) * sqrt(2.0)) * 0.5;
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -2.45e+188], N[(N[Sqrt[N[(N[((-re) + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[re, 1.04e-120], N[(N[(N[Sqrt[im], $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -2.45 \cdot 10^{+188}:\\
\;\;\;\;\sqrt{\left(\left(-re\right) + re\right) \cdot 2} \cdot 0.5\\

\mathbf{elif}\;re \leq 1.04 \cdot 10^{-120}:\\
\;\;\;\;\left(\sqrt{im} \cdot \sqrt{2}\right) \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\sqrt{re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -2.45e188

    1. Initial program 2.3%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\color{blue}{\left(\mathsf{neg}\left(re\right)\right)} + re\right)} \]
      2. lower-neg.f6439.6

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\left(-re\right)} + re\right)} \]
    5. Applied rewrites39.6%

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

    if -2.45e188 < re < 1.03999999999999994e-120

    1. Initial program 43.4%

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \left(\color{blue}{\sqrt{2}} \cdot \sqrt{im}\right) \]
      4. lower-sqrt.f6438.4

        \[\leadsto 0.5 \cdot \left(\sqrt{2} \cdot \color{blue}{\sqrt{im}}\right) \]
    5. Applied rewrites38.4%

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

    if 1.03999999999999994e-120 < 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 inf

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
      2. unpow2N/A

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

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

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

        \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
      6. *-lft-identityN/A

        \[\leadsto \color{blue}{\sqrt{re}} \]
      7. lower-sqrt.f6471.8

        \[\leadsto \color{blue}{\sqrt{re}} \]
    5. Applied rewrites71.8%

      \[\leadsto \color{blue}{\sqrt{re}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification52.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -2.45 \cdot 10^{+188}:\\ \;\;\;\;\sqrt{\left(\left(-re\right) + re\right) \cdot 2} \cdot 0.5\\ \mathbf{elif}\;re \leq 1.04 \cdot 10^{-120}:\\ \;\;\;\;\left(\sqrt{im} \cdot \sqrt{2}\right) \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 44.4% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -1.3 \cdot 10^{+161}:\\ \;\;\;\;\sqrt{\left(\left(-re\right) + re\right) \cdot 2} \cdot 0.5\\ \mathbf{elif}\;re \leq 130000000:\\ \;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -1.3e+161)
   (* (sqrt (* (+ (- re) re) 2.0)) 0.5)
   (if (<= re 130000000.0) (* (sqrt (* (+ im re) 2.0)) 0.5) (sqrt re))))
double code(double re, double im) {
	double tmp;
	if (re <= -1.3e+161) {
		tmp = sqrt(((-re + re) * 2.0)) * 0.5;
	} else if (re <= 130000000.0) {
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	} else {
		tmp = 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 <= (-1.3d+161)) then
        tmp = sqrt(((-re + re) * 2.0d0)) * 0.5d0
    else if (re <= 130000000.0d0) then
        tmp = sqrt(((im + re) * 2.0d0)) * 0.5d0
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -1.3e+161) {
		tmp = Math.sqrt(((-re + re) * 2.0)) * 0.5;
	} else if (re <= 130000000.0) {
		tmp = Math.sqrt(((im + re) * 2.0)) * 0.5;
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -1.3e+161:
		tmp = math.sqrt(((-re + re) * 2.0)) * 0.5
	elif re <= 130000000.0:
		tmp = math.sqrt(((im + re) * 2.0)) * 0.5
	else:
		tmp = math.sqrt(re)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -1.3e+161)
		tmp = Float64(sqrt(Float64(Float64(Float64(-re) + re) * 2.0)) * 0.5);
	elseif (re <= 130000000.0)
		tmp = Float64(sqrt(Float64(Float64(im + re) * 2.0)) * 0.5);
	else
		tmp = sqrt(re);
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -1.3e+161)
		tmp = sqrt(((-re + re) * 2.0)) * 0.5;
	elseif (re <= 130000000.0)
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -1.3e+161], N[(N[Sqrt[N[(N[((-re) + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[re, 130000000.0], N[(N[Sqrt[N[(N[(im + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -1.3 \cdot 10^{+161}:\\
\;\;\;\;\sqrt{\left(\left(-re\right) + re\right) \cdot 2} \cdot 0.5\\

\mathbf{elif}\;re \leq 130000000:\\
\;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\sqrt{re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -1.2999999999999999e161

    1. Initial program 2.3%

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\color{blue}{\left(\mathsf{neg}\left(re\right)\right)} + re\right)} \]
      2. lower-neg.f6435.1

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\color{blue}{\left(-re\right)} + re\right)} \]
    5. Applied rewrites35.1%

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

    if -1.2999999999999999e161 < re < 1.3e8

    1. Initial program 51.2%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + re\right)}} \]
    4. Step-by-step derivation
      1. lower-+.f6438.7

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im + re\right)}} \]
    5. Applied rewrites38.7%

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

    if 1.3e8 < re

    1. Initial program 39.0%

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

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
      2. unpow2N/A

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

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

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

        \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
      6. *-lft-identityN/A

        \[\leadsto \color{blue}{\sqrt{re}} \]
      7. lower-sqrt.f6477.8

        \[\leadsto \color{blue}{\sqrt{re}} \]
    5. Applied rewrites77.8%

      \[\leadsto \color{blue}{\sqrt{re}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification50.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -1.3 \cdot 10^{+161}:\\ \;\;\;\;\sqrt{\left(\left(-re\right) + re\right) \cdot 2} \cdot 0.5\\ \mathbf{elif}\;re \leq 130000000:\\ \;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
  5. Add Preprocessing

Alternative 8: 43.2% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq 1.04 \cdot 10^{-120}:\\ \;\;\;\;\sqrt{im \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re 1.04e-120) (* (sqrt (* im 2.0)) 0.5) (sqrt re)))
double code(double re, double im) {
	double tmp;
	if (re <= 1.04e-120) {
		tmp = sqrt((im * 2.0)) * 0.5;
	} else {
		tmp = 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 <= 1.04d-120) then
        tmp = sqrt((im * 2.0d0)) * 0.5d0
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= 1.04e-120) {
		tmp = Math.sqrt((im * 2.0)) * 0.5;
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= 1.04e-120:
		tmp = math.sqrt((im * 2.0)) * 0.5
	else:
		tmp = math.sqrt(re)
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= 1.04e-120)
		tmp = Float64(sqrt(Float64(im * 2.0)) * 0.5);
	else
		tmp = sqrt(re);
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= 1.04e-120)
		tmp = sqrt((im * 2.0)) * 0.5;
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, 1.04e-120], N[(N[Sqrt[N[(im * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq 1.04 \cdot 10^{-120}:\\
\;\;\;\;\sqrt{im \cdot 2} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\sqrt{re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < 1.03999999999999994e-120

    1. Initial program 36.1%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    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. lower-*.f6432.4

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{2 \cdot im}} \]
    5. Applied rewrites32.4%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{2 \cdot im}} \]

    if 1.03999999999999994e-120 < 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 inf

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

        \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
      2. unpow2N/A

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

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

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

        \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
      6. *-lft-identityN/A

        \[\leadsto \color{blue}{\sqrt{re}} \]
      7. lower-sqrt.f6471.8

        \[\leadsto \color{blue}{\sqrt{re}} \]
    5. Applied rewrites71.8%

      \[\leadsto \color{blue}{\sqrt{re}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification48.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq 1.04 \cdot 10^{-120}:\\ \;\;\;\;\sqrt{im \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
  5. Add Preprocessing

Alternative 9: 26.0% accurate, 4.3× speedup?

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

\\
\sqrt{re}
\end{array}
Derivation
  1. Initial program 41.6%

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

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

      \[\leadsto \frac{1}{2} \cdot \color{blue}{\left({\left(\sqrt{2}\right)}^{2} \cdot \sqrt{re}\right)} \]
    2. unpow2N/A

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

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

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

      \[\leadsto \color{blue}{1} \cdot \sqrt{re} \]
    6. *-lft-identityN/A

      \[\leadsto \color{blue}{\sqrt{re}} \]
    7. lower-sqrt.f6431.4

      \[\leadsto \color{blue}{\sqrt{re}} \]
  5. Applied rewrites31.4%

    \[\leadsto \color{blue}{\sqrt{re}} \]
  6. Add Preprocessing

Developer Target 1: 48.6% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{re \cdot re + im \cdot im}\\ \mathbf{if}\;re < 0:\\ \;\;\;\;0.5 \cdot \left(\sqrt{2} \cdot \sqrt{\frac{im \cdot im}{t\_0 - re}}\right)\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(t\_0 + re\right)}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (let* ((t_0 (sqrt (+ (* re re) (* im im)))))
   (if (< re 0.0)
     (* 0.5 (* (sqrt 2.0) (sqrt (/ (* im im) (- t_0 re)))))
     (* 0.5 (sqrt (* 2.0 (+ t_0 re)))))))
double code(double re, double im) {
	double t_0 = sqrt(((re * re) + (im * im)));
	double tmp;
	if (re < 0.0) {
		tmp = 0.5 * (sqrt(2.0) * sqrt(((im * im) / (t_0 - re))));
	} else {
		tmp = 0.5 * sqrt((2.0 * (t_0 + re)));
	}
	return tmp;
}
real(8) function code(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sqrt(((re * re) + (im * im)))
    if (re < 0.0d0) then
        tmp = 0.5d0 * (sqrt(2.0d0) * sqrt(((im * im) / (t_0 - re))))
    else
        tmp = 0.5d0 * sqrt((2.0d0 * (t_0 + re)))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double t_0 = Math.sqrt(((re * re) + (im * im)));
	double tmp;
	if (re < 0.0) {
		tmp = 0.5 * (Math.sqrt(2.0) * Math.sqrt(((im * im) / (t_0 - re))));
	} else {
		tmp = 0.5 * Math.sqrt((2.0 * (t_0 + re)));
	}
	return tmp;
}
def code(re, im):
	t_0 = math.sqrt(((re * re) + (im * im)))
	tmp = 0
	if re < 0.0:
		tmp = 0.5 * (math.sqrt(2.0) * math.sqrt(((im * im) / (t_0 - re))))
	else:
		tmp = 0.5 * math.sqrt((2.0 * (t_0 + re)))
	return tmp
function code(re, im)
	t_0 = sqrt(Float64(Float64(re * re) + Float64(im * im)))
	tmp = 0.0
	if (re < 0.0)
		tmp = Float64(0.5 * Float64(sqrt(2.0) * sqrt(Float64(Float64(im * im) / Float64(t_0 - re)))));
	else
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(t_0 + re))));
	end
	return tmp
end
function tmp_2 = code(re, im)
	t_0 = sqrt(((re * re) + (im * im)));
	tmp = 0.0;
	if (re < 0.0)
		tmp = 0.5 * (sqrt(2.0) * sqrt(((im * im) / (t_0 - re))));
	else
		tmp = 0.5 * sqrt((2.0 * (t_0 + re)));
	end
	tmp_2 = tmp;
end
code[re_, im_] := Block[{t$95$0 = N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[Less[re, 0.0], N[(0.5 * N[(N[Sqrt[2.0], $MachinePrecision] * N[Sqrt[N[(N[(im * im), $MachinePrecision] / N[(t$95$0 - re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(2.0 * N[(t$95$0 + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

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

\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(t\_0 + re\right)}\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024276 
(FPCore (re im)
  :name "math.sqrt on complex, real part"
  :precision binary64

  :alt
  (! :herbie-platform default (if (< re 0) (* 1/2 (* (sqrt 2) (sqrt (/ (* im im) (- (modulus re im) re))))) (* 1/2 (sqrt (* 2 (+ (modulus re im) re))))))

  (* 0.5 (sqrt (* 2.0 (+ (sqrt (+ (* re re) (* im im))) re)))))