math.sqrt on complex, real part

Percentage Accurate: 40.7% → 84.3%
Time: 7.3s
Alternatives: 6
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 6 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: 40.7% 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: 84.3% accurate, 0.3× speedup?

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

\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 (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re) < 0.0

    1. Initial program 13.7%

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

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

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

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{\left(\mathsf{neg}\left(im\right)\right)} \cdot im}{re}} \]
      7. lower-neg.f6447.6

        \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{\left(-im\right)} \cdot im}{re}} \]
    5. Applied rewrites47.6%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{\left(-im\right) \cdot im}{re}}} \]
    6. Applied rewrites66.4%

      \[\leadsto 0.5 \cdot \sqrt{-\frac{im}{re} \cdot im} \]
    7. Step-by-step derivation
      1. Applied rewrites66.2%

        \[\leadsto 0.5 \cdot \sqrt{-\frac{im}{\frac{re}{im}}} \]
      2. Step-by-step derivation
        1. Applied rewrites66.4%

          \[\leadsto 0.5 \cdot \sqrt{\frac{\frac{im}{re}}{\color{blue}{\frac{-1}{im}}}} \]

        if 0.0 < (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re)

        1. Initial program 46.1%

          \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
        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. lower-*.f6446.1

            \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \cdot 0.5} \]
          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-*.f6446.1

            \[\leadsto \sqrt{\color{blue}{\left(\sqrt{re \cdot re + im \cdot im} + re\right) \cdot 2}} \cdot 0.5 \]
          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.f6490.2

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

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

      Alternative 2: 55.9% accurate, 0.7× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -0.0142:\\ \;\;\;\;0.5 \cdot \sqrt{\frac{\frac{im}{re}}{\frac{-1}{im}}}\\ \mathbf{elif}\;re \leq 4.2 \cdot 10^{-87}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \mathbf{elif}\;re \leq 3.4 \cdot 10^{+137}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
      (FPCore (re im)
       :precision binary64
       (if (<= re -0.0142)
         (* 0.5 (sqrt (/ (/ im re) (/ -1.0 im))))
         (if (<= re 4.2e-87)
           (* 0.5 (sqrt (* 2.0 im)))
           (if (<= re 3.4e+137)
             (* 0.5 (sqrt (* 2.0 (+ (sqrt (fma re re (* im im))) re))))
             (sqrt re)))))
      double code(double re, double im) {
      	double tmp;
      	if (re <= -0.0142) {
      		tmp = 0.5 * sqrt(((im / re) / (-1.0 / im)));
      	} else if (re <= 4.2e-87) {
      		tmp = 0.5 * sqrt((2.0 * im));
      	} else if (re <= 3.4e+137) {
      		tmp = 0.5 * sqrt((2.0 * (sqrt(fma(re, re, (im * im))) + re)));
      	} else {
      		tmp = sqrt(re);
      	}
      	return tmp;
      }
      
      function code(re, im)
      	tmp = 0.0
      	if (re <= -0.0142)
      		tmp = Float64(0.5 * sqrt(Float64(Float64(im / re) / Float64(-1.0 / im))));
      	elseif (re <= 4.2e-87)
      		tmp = Float64(0.5 * sqrt(Float64(2.0 * im)));
      	elseif (re <= 3.4e+137)
      		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(fma(re, re, Float64(im * im))) + re))));
      	else
      		tmp = sqrt(re);
      	end
      	return tmp
      end
      
      code[re_, im_] := If[LessEqual[re, -0.0142], N[(0.5 * N[Sqrt[N[(N[(im / re), $MachinePrecision] / N[(-1.0 / im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 4.2e-87], N[(0.5 * N[Sqrt[N[(2.0 * im), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 3.4e+137], N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(re * re + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      \mathbf{if}\;re \leq -0.0142:\\
      \;\;\;\;0.5 \cdot \sqrt{\frac{\frac{im}{re}}{\frac{-1}{im}}}\\
      
      \mathbf{elif}\;re \leq 4.2 \cdot 10^{-87}:\\
      \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\
      
      \mathbf{elif}\;re \leq 3.4 \cdot 10^{+137}:\\
      \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right)}\\
      
      \mathbf{else}:\\
      \;\;\;\;\sqrt{re}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 4 regimes
      2. if re < -0.014200000000000001

        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

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

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

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

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

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

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

            \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{\left(\mathsf{neg}\left(im\right)\right)} \cdot im}{re}} \]
          7. lower-neg.f6449.7

            \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{\left(-im\right)} \cdot im}{re}} \]
        5. Applied rewrites49.7%

          \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{\left(-im\right) \cdot im}{re}}} \]
        6. Applied rewrites60.5%

          \[\leadsto 0.5 \cdot \sqrt{-\frac{im}{re} \cdot im} \]
        7. Step-by-step derivation
          1. Applied rewrites60.4%

            \[\leadsto 0.5 \cdot \sqrt{-\frac{im}{\frac{re}{im}}} \]
          2. Step-by-step derivation
            1. Applied rewrites60.6%

              \[\leadsto 0.5 \cdot \sqrt{\frac{\frac{im}{re}}{\color{blue}{\frac{-1}{im}}}} \]

            if -0.014200000000000001 < re < 4.20000000000000014e-87

            1. Initial program 52.9%

              \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
            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-*.f6436.6

                \[\leadsto 0.5 \cdot \sqrt{\color{blue}{2 \cdot im}} \]
            5. Applied rewrites36.6%

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

            if 4.20000000000000014e-87 < re < 3.39999999999999986e137

            1. Initial program 75.1%

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

                \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{re \cdot re} + im \cdot im} + re\right)} \]
              3. lower-fma.f6475.1

                \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{\mathsf{fma}\left(re, re, im \cdot im\right)}} + re\right)} \]
            4. Applied rewrites75.1%

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

            if 3.39999999999999986e137 < re

            1. Initial program 4.2%

              \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
            2. Add Preprocessing
            3. Taylor expanded in re around 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.f6490.7

                \[\leadsto \color{blue}{\sqrt{re}} \]
            5. Applied rewrites90.7%

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

          Alternative 3: 55.9% accurate, 0.7× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -0.0142:\\ \;\;\;\;0.5 \cdot \sqrt{\frac{im}{re} \cdot \left(-im\right)}\\ \mathbf{elif}\;re \leq 4.2 \cdot 10^{-87}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \mathbf{elif}\;re \leq 3.4 \cdot 10^{+137}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
          (FPCore (re im)
           :precision binary64
           (if (<= re -0.0142)
             (* 0.5 (sqrt (* (/ im re) (- im))))
             (if (<= re 4.2e-87)
               (* 0.5 (sqrt (* 2.0 im)))
               (if (<= re 3.4e+137)
                 (* 0.5 (sqrt (* 2.0 (+ (sqrt (fma re re (* im im))) re))))
                 (sqrt re)))))
          double code(double re, double im) {
          	double tmp;
          	if (re <= -0.0142) {
          		tmp = 0.5 * sqrt(((im / re) * -im));
          	} else if (re <= 4.2e-87) {
          		tmp = 0.5 * sqrt((2.0 * im));
          	} else if (re <= 3.4e+137) {
          		tmp = 0.5 * sqrt((2.0 * (sqrt(fma(re, re, (im * im))) + re)));
          	} else {
          		tmp = sqrt(re);
          	}
          	return tmp;
          }
          
          function code(re, im)
          	tmp = 0.0
          	if (re <= -0.0142)
          		tmp = Float64(0.5 * sqrt(Float64(Float64(im / re) * Float64(-im))));
          	elseif (re <= 4.2e-87)
          		tmp = Float64(0.5 * sqrt(Float64(2.0 * im)));
          	elseif (re <= 3.4e+137)
          		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(fma(re, re, Float64(im * im))) + re))));
          	else
          		tmp = sqrt(re);
          	end
          	return tmp
          end
          
          code[re_, im_] := If[LessEqual[re, -0.0142], N[(0.5 * N[Sqrt[N[(N[(im / re), $MachinePrecision] * (-im)), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 4.2e-87], N[(0.5 * N[Sqrt[N[(2.0 * im), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 3.4e+137], N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(re * re + N[(im * im), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          \mathbf{if}\;re \leq -0.0142:\\
          \;\;\;\;0.5 \cdot \sqrt{\frac{im}{re} \cdot \left(-im\right)}\\
          
          \mathbf{elif}\;re \leq 4.2 \cdot 10^{-87}:\\
          \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\
          
          \mathbf{elif}\;re \leq 3.4 \cdot 10^{+137}:\\
          \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right)}\\
          
          \mathbf{else}:\\
          \;\;\;\;\sqrt{re}\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 4 regimes
          2. if re < -0.014200000000000001

            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

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

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

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

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

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

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

                \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{\left(\mathsf{neg}\left(im\right)\right)} \cdot im}{re}} \]
              7. lower-neg.f6449.7

                \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{\left(-im\right)} \cdot im}{re}} \]
            5. Applied rewrites49.7%

              \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{\left(-im\right) \cdot im}{re}}} \]
            6. Applied rewrites60.5%

              \[\leadsto 0.5 \cdot \sqrt{-\frac{im}{re} \cdot im} \]

            if -0.014200000000000001 < re < 4.20000000000000014e-87

            1. Initial program 52.9%

              \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
            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-*.f6436.6

                \[\leadsto 0.5 \cdot \sqrt{\color{blue}{2 \cdot im}} \]
            5. Applied rewrites36.6%

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

            if 4.20000000000000014e-87 < re < 3.39999999999999986e137

            1. Initial program 75.1%

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

                \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{re \cdot re} + im \cdot im} + re\right)} \]
              3. lower-fma.f6475.1

                \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\color{blue}{\mathsf{fma}\left(re, re, im \cdot im\right)}} + re\right)} \]
            4. Applied rewrites75.1%

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

            if 3.39999999999999986e137 < re

            1. Initial program 4.2%

              \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
            2. Add Preprocessing
            3. Taylor expanded in re around 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.f6490.7

                \[\leadsto \color{blue}{\sqrt{re}} \]
            5. Applied rewrites90.7%

              \[\leadsto \color{blue}{\sqrt{re}} \]
          3. Recombined 4 regimes into one program.
          4. Final simplification57.5%

            \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -0.0142:\\ \;\;\;\;0.5 \cdot \sqrt{\frac{im}{re} \cdot \left(-im\right)}\\ \mathbf{elif}\;re \leq 4.2 \cdot 10^{-87}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \mathbf{elif}\;re \leq 3.4 \cdot 10^{+137}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im \cdot im\right)} + re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
          5. Add Preprocessing

          Alternative 4: 51.5% accurate, 1.2× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -2.15 \cdot 10^{-60}:\\ \;\;\;\;0.5 \cdot \sqrt{\frac{im}{re} \cdot \left(-im\right)}\\ \mathbf{elif}\;re \leq 5.8 \cdot 10^{+48}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im + re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
          (FPCore (re im)
           :precision binary64
           (if (<= re -2.15e-60)
             (* 0.5 (sqrt (* (/ im re) (- im))))
             (if (<= re 5.8e+48) (* 0.5 (sqrt (* 2.0 (+ im re)))) (sqrt re))))
          double code(double re, double im) {
          	double tmp;
          	if (re <= -2.15e-60) {
          		tmp = 0.5 * sqrt(((im / re) * -im));
          	} else if (re <= 5.8e+48) {
          		tmp = 0.5 * sqrt((2.0 * (im + re)));
          	} 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 <= (-2.15d-60)) then
                  tmp = 0.5d0 * sqrt(((im / re) * -im))
              else if (re <= 5.8d+48) then
                  tmp = 0.5d0 * sqrt((2.0d0 * (im + re)))
              else
                  tmp = sqrt(re)
              end if
              code = tmp
          end function
          
          public static double code(double re, double im) {
          	double tmp;
          	if (re <= -2.15e-60) {
          		tmp = 0.5 * Math.sqrt(((im / re) * -im));
          	} else if (re <= 5.8e+48) {
          		tmp = 0.5 * Math.sqrt((2.0 * (im + re)));
          	} else {
          		tmp = Math.sqrt(re);
          	}
          	return tmp;
          }
          
          def code(re, im):
          	tmp = 0
          	if re <= -2.15e-60:
          		tmp = 0.5 * math.sqrt(((im / re) * -im))
          	elif re <= 5.8e+48:
          		tmp = 0.5 * math.sqrt((2.0 * (im + re)))
          	else:
          		tmp = math.sqrt(re)
          	return tmp
          
          function code(re, im)
          	tmp = 0.0
          	if (re <= -2.15e-60)
          		tmp = Float64(0.5 * sqrt(Float64(Float64(im / re) * Float64(-im))));
          	elseif (re <= 5.8e+48)
          		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im + re))));
          	else
          		tmp = sqrt(re);
          	end
          	return tmp
          end
          
          function tmp_2 = code(re, im)
          	tmp = 0.0;
          	if (re <= -2.15e-60)
          		tmp = 0.5 * sqrt(((im / re) * -im));
          	elseif (re <= 5.8e+48)
          		tmp = 0.5 * sqrt((2.0 * (im + re)));
          	else
          		tmp = sqrt(re);
          	end
          	tmp_2 = tmp;
          end
          
          code[re_, im_] := If[LessEqual[re, -2.15e-60], N[(0.5 * N[Sqrt[N[(N[(im / re), $MachinePrecision] * (-im)), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 5.8e+48], N[(0.5 * N[Sqrt[N[(2.0 * N[(im + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          \mathbf{if}\;re \leq -2.15 \cdot 10^{-60}:\\
          \;\;\;\;0.5 \cdot \sqrt{\frac{im}{re} \cdot \left(-im\right)}\\
          
          \mathbf{elif}\;re \leq 5.8 \cdot 10^{+48}:\\
          \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im + re\right)}\\
          
          \mathbf{else}:\\
          \;\;\;\;\sqrt{re}\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 3 regimes
          2. if re < -2.15e-60

            1. Initial program 15.3%

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

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

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

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

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

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

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

                \[\leadsto \frac{1}{2} \cdot \sqrt{\frac{\color{blue}{\left(\mathsf{neg}\left(im\right)\right)} \cdot im}{re}} \]
              7. lower-neg.f6447.1

                \[\leadsto 0.5 \cdot \sqrt{\frac{\color{blue}{\left(-im\right)} \cdot im}{re}} \]
            5. Applied rewrites47.1%

              \[\leadsto 0.5 \cdot \sqrt{\color{blue}{\frac{\left(-im\right) \cdot im}{re}}} \]
            6. Applied rewrites57.9%

              \[\leadsto 0.5 \cdot \sqrt{-\frac{im}{re} \cdot im} \]

            if -2.15e-60 < re < 5.7999999999999998e48

            1. Initial program 59.3%

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

              \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{\left(im + re\right)}} \]
            4. Step-by-step derivation
              1. lower-+.f6439.1

                \[\leadsto 0.5 \cdot \sqrt{2 \cdot \color{blue}{\left(im + re\right)}} \]
            5. Applied rewrites39.1%

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

            if 5.7999999999999998e48 < re

            1. Initial program 30.2%

              \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
            2. Add Preprocessing
            3. Taylor expanded in re around 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.f6483.3

                \[\leadsto \color{blue}{\sqrt{re}} \]
            5. Applied rewrites83.3%

              \[\leadsto \color{blue}{\sqrt{re}} \]
          3. Recombined 3 regimes into one program.
          4. Final simplification54.1%

            \[\leadsto \begin{array}{l} \mathbf{if}\;re \leq -2.15 \cdot 10^{-60}:\\ \;\;\;\;0.5 \cdot \sqrt{\frac{im}{re} \cdot \left(-im\right)}\\ \mathbf{elif}\;re \leq 5.8 \cdot 10^{+48}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im + re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \]
          5. Add Preprocessing

          Alternative 5: 42.2% accurate, 1.7× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq 7.7 \cdot 10^{-78}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
          (FPCore (re im)
           :precision binary64
           (if (<= re 7.7e-78) (* 0.5 (sqrt (* 2.0 im))) (sqrt re)))
          double code(double re, double im) {
          	double tmp;
          	if (re <= 7.7e-78) {
          		tmp = 0.5 * sqrt((2.0 * im));
          	} 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 <= 7.7d-78) then
                  tmp = 0.5d0 * sqrt((2.0d0 * im))
              else
                  tmp = sqrt(re)
              end if
              code = tmp
          end function
          
          public static double code(double re, double im) {
          	double tmp;
          	if (re <= 7.7e-78) {
          		tmp = 0.5 * Math.sqrt((2.0 * im));
          	} else {
          		tmp = Math.sqrt(re);
          	}
          	return tmp;
          }
          
          def code(re, im):
          	tmp = 0
          	if re <= 7.7e-78:
          		tmp = 0.5 * math.sqrt((2.0 * im))
          	else:
          		tmp = math.sqrt(re)
          	return tmp
          
          function code(re, im)
          	tmp = 0.0
          	if (re <= 7.7e-78)
          		tmp = Float64(0.5 * sqrt(Float64(2.0 * im)));
          	else
          		tmp = sqrt(re);
          	end
          	return tmp
          end
          
          function tmp_2 = code(re, im)
          	tmp = 0.0;
          	if (re <= 7.7e-78)
          		tmp = 0.5 * sqrt((2.0 * im));
          	else
          		tmp = sqrt(re);
          	end
          	tmp_2 = tmp;
          end
          
          code[re_, im_] := If[LessEqual[re, 7.7e-78], N[(0.5 * N[Sqrt[N[(2.0 * im), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          \mathbf{if}\;re \leq 7.7 \cdot 10^{-78}:\\
          \;\;\;\;0.5 \cdot \sqrt{2 \cdot im}\\
          
          \mathbf{else}:\\
          \;\;\;\;\sqrt{re}\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if re < 7.7000000000000001e-78

            1. Initial program 40.7%

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

              \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{2 \cdot im}} \]
            4. Step-by-step derivation
              1. lower-*.f6428.4

                \[\leadsto 0.5 \cdot \sqrt{\color{blue}{2 \cdot im}} \]
            5. Applied rewrites28.4%

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

            if 7.7000000000000001e-78 < re

            1. Initial program 42.8%

              \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
            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.f6473.6

                \[\leadsto \color{blue}{\sqrt{re}} \]
            5. Applied rewrites73.6%

              \[\leadsto \color{blue}{\sqrt{re}} \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 6: 27.4% 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 41.4%

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

            \[\leadsto \color{blue}{\frac{1}{2} \cdot \left(\sqrt{re} \cdot {\left(\sqrt{2}\right)}^{2}\right)} \]
          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.f6429.6

              \[\leadsto \color{blue}{\sqrt{re}} \]
          5. Applied rewrites29.6%

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

          Developer Target 1: 48.0% 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 2024322 
          (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)))))