math.sqrt on complex, real part

Percentage Accurate: 41.0% → 84.2%
Time: 4.3s
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)));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(re, im)
use fmin_fmax_functions
    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}

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: 41.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \end{array} \]
(FPCore (re im)
 :precision binary64
 (* 0.5 (sqrt (* 2.0 (+ (sqrt (+ (* re re) (* im im))) re)))))
double code(double re, double im) {
	return 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) + re)));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(re, im)
use fmin_fmax_functions
    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: 84.2% accurate, 0.4× speedup?

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

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

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


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

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{\color{blue}{re}}} \]
      3. lower-pow.f6415.1

        \[\leadsto 0.5 \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{re}} \]
    4. Applied rewrites15.1%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

        \[\leadsto \color{blue}{\sqrt{-1 \cdot \frac{{im}^{2}}{re}} \cdot \frac{1}{2}} \]
      3. lower-*.f6415.1

        \[\leadsto \color{blue}{\sqrt{-1 \cdot \frac{{im}^{2}}{re}} \cdot 0.5} \]
      4. lift-*.f64N/A

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

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

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

        \[\leadsto \sqrt{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)} \cdot \frac{1}{2} \]
      8. pow2N/A

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

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

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

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

        \[\leadsto \sqrt{\left(-im\right) \cdot \frac{\color{blue}{im}}{re}} \cdot \frac{1}{2} \]
      13. lower-/.f6418.3

        \[\leadsto \sqrt{\left(-im\right) \cdot \frac{im}{\color{blue}{re}}} \cdot 0.5 \]
    6. Applied rewrites18.3%

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

    if 0.0 < (*.f64 #s(literal 1/2 binary64) (sqrt.f64 (*.f64 #s(literal 2 binary64) (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re))))

    1. Initial program 41.0%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. 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-*.f6441.0

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \cdot 0.5} \]
    3. Applied rewrites41.0%

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

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

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

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

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

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

        \[\leadsto \sqrt{\left(\color{blue}{\sqrt{re \cdot re + im \cdot im}} + re\right) \cdot 2} \cdot \frac{1}{2} \]
      7. lower-hypot.f6478.3

        \[\leadsto \sqrt{\left(\color{blue}{\mathsf{hypot}\left(re, im\right)} + re\right) \cdot 2} \cdot 0.5 \]
    5. Applied rewrites78.3%

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

Alternative 2: 59.1% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)}\\ \mathbf{if}\;t\_0 \leq 0:\\ \;\;\;\;\sqrt{\left(-im\right) \cdot \frac{im}{re}} \cdot 0.5\\ \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{-89}:\\ \;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\ \mathbf{elif}\;t\_0 \leq 2 \cdot 10^{+71}:\\ \;\;\;\;\sqrt{\left(\sqrt{\mathsf{fma}\left(im, im, re \cdot re\right)} + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (let* ((t_0 (* 0.5 (sqrt (* 2.0 (+ (sqrt (+ (* re re) (* im im))) re))))))
   (if (<= t_0 0.0)
     (* (sqrt (* (- im) (/ im re))) 0.5)
     (if (<= t_0 5e-89)
       (* 0.5 (sqrt (* 4.0 re)))
       (if (<= t_0 2e+71)
         (* (sqrt (* (+ (sqrt (fma im im (* re re))) re) 2.0)) 0.5)
         (* (sqrt (* (+ im re) 2.0)) 0.5))))))
double code(double re, double im) {
	double t_0 = 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) + re)));
	double tmp;
	if (t_0 <= 0.0) {
		tmp = sqrt((-im * (im / re))) * 0.5;
	} else if (t_0 <= 5e-89) {
		tmp = 0.5 * sqrt((4.0 * re));
	} else if (t_0 <= 2e+71) {
		tmp = sqrt(((sqrt(fma(im, im, (re * re))) + re) * 2.0)) * 0.5;
	} else {
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	}
	return tmp;
}
function code(re, im)
	t_0 = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im * im))) + re))))
	tmp = 0.0
	if (t_0 <= 0.0)
		tmp = Float64(sqrt(Float64(Float64(-im) * Float64(im / re))) * 0.5);
	elseif (t_0 <= 5e-89)
		tmp = Float64(0.5 * sqrt(Float64(4.0 * re)));
	elseif (t_0 <= 2e+71)
		tmp = Float64(sqrt(Float64(Float64(sqrt(fma(im, im, Float64(re * re))) + re) * 2.0)) * 0.5);
	else
		tmp = Float64(sqrt(Float64(Float64(im + re) * 2.0)) * 0.5);
	end
	return tmp
end
code[re_, im_] := Block[{t$95$0 = 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]}, If[LessEqual[t$95$0, 0.0], N[(N[Sqrt[N[((-im) * N[(im / re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[t$95$0, 5e-89], N[(0.5 * N[Sqrt[N[(4.0 * re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$0, 2e+71], N[(N[Sqrt[N[(N[(N[Sqrt[N[(im * im + N[(re * re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[(N[Sqrt[N[(N[(im + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]]]]]
\begin{array}{l}

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

\mathbf{elif}\;t\_0 \leq 5 \cdot 10^{-89}:\\
\;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\

\mathbf{elif}\;t\_0 \leq 2 \cdot 10^{+71}:\\
\;\;\;\;\sqrt{\left(\sqrt{\mathsf{fma}\left(im, im, re \cdot re\right)} + re\right) \cdot 2} \cdot 0.5\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 4 regimes
  2. if (*.f64 #s(literal 1/2 binary64) (sqrt.f64 (*.f64 #s(literal 2 binary64) (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re)))) < 0.0

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{\color{blue}{re}}} \]
      3. lower-pow.f6415.1

        \[\leadsto 0.5 \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{re}} \]
    4. Applied rewrites15.1%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

        \[\leadsto \color{blue}{\sqrt{-1 \cdot \frac{{im}^{2}}{re}} \cdot \frac{1}{2}} \]
      3. lower-*.f6415.1

        \[\leadsto \color{blue}{\sqrt{-1 \cdot \frac{{im}^{2}}{re}} \cdot 0.5} \]
      4. lift-*.f64N/A

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

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

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

        \[\leadsto \sqrt{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)} \cdot \frac{1}{2} \]
      8. pow2N/A

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

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

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

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

        \[\leadsto \sqrt{\left(-im\right) \cdot \frac{\color{blue}{im}}{re}} \cdot \frac{1}{2} \]
      13. lower-/.f6418.3

        \[\leadsto \sqrt{\left(-im\right) \cdot \frac{im}{\color{blue}{re}}} \cdot 0.5 \]
    6. Applied rewrites18.3%

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

    if 0.0 < (*.f64 #s(literal 1/2 binary64) (sqrt.f64 (*.f64 #s(literal 2 binary64) (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re)))) < 4.99999999999999967e-89

    1. Initial program 41.0%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{4 \cdot re}} \]
    3. Step-by-step derivation
      1. lower-*.f6425.7

        \[\leadsto 0.5 \cdot \sqrt{4 \cdot \color{blue}{re}} \]
    4. Applied rewrites25.7%

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

    if 4.99999999999999967e-89 < (*.f64 #s(literal 1/2 binary64) (sqrt.f64 (*.f64 #s(literal 2 binary64) (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re)))) < 2.0000000000000001e71

    1. Initial program 41.0%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. 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-*.f6441.0

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \cdot 0.5} \]
    3. Applied rewrites41.0%

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

    if 2.0000000000000001e71 < (*.f64 #s(literal 1/2 binary64) (sqrt.f64 (*.f64 #s(literal 2 binary64) (+.f64 (sqrt.f64 (+.f64 (*.f64 re re) (*.f64 im im))) re))))

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \color{blue}{\frac{re}{im}}\right)\right)} \]
      3. lower-/.f6429.9

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{\color{blue}{im}}\right)\right)} \]
    4. Applied rewrites29.9%

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

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

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot \frac{1}{2}} \]
      3. lower-*.f6429.9

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot 0.5} \]
    6. Applied rewrites30.8%

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

Alternative 3: 50.3% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -5 \cdot 10^{+156}:\\ \;\;\;\;0.5 \cdot \sqrt{im \cdot \left(im \cdot \frac{-1}{re}\right)}\\ \mathbf{elif}\;re \leq 255000000000:\\ \;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -5e+156)
   (* 0.5 (sqrt (* im (* im (/ -1.0 re)))))
   (if (<= re 255000000000.0)
     (* (sqrt (* (+ im re) 2.0)) 0.5)
     (* 0.5 (sqrt (* 4.0 re))))))
double code(double re, double im) {
	double tmp;
	if (re <= -5e+156) {
		tmp = 0.5 * sqrt((im * (im * (-1.0 / re))));
	} else if (re <= 255000000000.0) {
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	} else {
		tmp = 0.5 * sqrt((4.0 * re));
	}
	return tmp;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(re, im)
use fmin_fmax_functions
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-5d+156)) then
        tmp = 0.5d0 * sqrt((im * (im * ((-1.0d0) / re))))
    else if (re <= 255000000000.0d0) then
        tmp = sqrt(((im + re) * 2.0d0)) * 0.5d0
    else
        tmp = 0.5d0 * sqrt((4.0d0 * re))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -5e+156) {
		tmp = 0.5 * Math.sqrt((im * (im * (-1.0 / re))));
	} else if (re <= 255000000000.0) {
		tmp = Math.sqrt(((im + re) * 2.0)) * 0.5;
	} else {
		tmp = 0.5 * Math.sqrt((4.0 * re));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -5e+156:
		tmp = 0.5 * math.sqrt((im * (im * (-1.0 / re))))
	elif re <= 255000000000.0:
		tmp = math.sqrt(((im + re) * 2.0)) * 0.5
	else:
		tmp = 0.5 * math.sqrt((4.0 * re))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -5e+156)
		tmp = Float64(0.5 * sqrt(Float64(im * Float64(im * Float64(-1.0 / re)))));
	elseif (re <= 255000000000.0)
		tmp = Float64(sqrt(Float64(Float64(im + re) * 2.0)) * 0.5);
	else
		tmp = Float64(0.5 * sqrt(Float64(4.0 * re)));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -5e+156)
		tmp = 0.5 * sqrt((im * (im * (-1.0 / re))));
	elseif (re <= 255000000000.0)
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	else
		tmp = 0.5 * sqrt((4.0 * re));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -5e+156], N[(0.5 * N[Sqrt[N[(im * N[(im * N[(-1.0 / re), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 255000000000.0], N[(N[Sqrt[N[(N[(im + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[(0.5 * N[Sqrt[N[(4.0 * re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -5 \cdot 10^{+156}:\\
\;\;\;\;0.5 \cdot \sqrt{im \cdot \left(im \cdot \frac{-1}{re}\right)}\\

\mathbf{elif}\;re \leq 255000000000:\\
\;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -4.99999999999999992e156

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{\color{blue}{re}}} \]
      3. lower-pow.f6415.1

        \[\leadsto 0.5 \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{re}} \]
    4. Applied rewrites15.1%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)} \]
      5. pow2N/A

        \[\leadsto \frac{1}{2} \cdot \sqrt{\mathsf{neg}\left(\frac{im \cdot im}{re}\right)} \]
      6. distribute-neg-frac2N/A

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

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

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

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{im \cdot \left(im \cdot \frac{-1}{\color{blue}{re}}\right)} \]
      13. lower-/.f6418.3

        \[\leadsto 0.5 \cdot \sqrt{im \cdot \left(im \cdot \frac{-1}{\color{blue}{re}}\right)} \]
    6. Applied rewrites18.3%

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

    if -4.99999999999999992e156 < re < 2.55e11

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \color{blue}{\frac{re}{im}}\right)\right)} \]
      3. lower-/.f6429.9

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{\color{blue}{im}}\right)\right)} \]
    4. Applied rewrites29.9%

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

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

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot \frac{1}{2}} \]
      3. lower-*.f6429.9

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot 0.5} \]
    6. Applied rewrites30.8%

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

    if 2.55e11 < re

    1. Initial program 41.0%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{4 \cdot re}} \]
    3. Step-by-step derivation
      1. lower-*.f6425.7

        \[\leadsto 0.5 \cdot \sqrt{4 \cdot \color{blue}{re}} \]
    4. Applied rewrites25.7%

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

Alternative 4: 50.3% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq -5 \cdot 10^{+156}:\\ \;\;\;\;\sqrt{\left(-im\right) \cdot \frac{im}{re}} \cdot 0.5\\ \mathbf{elif}\;re \leq 255000000000:\\ \;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re -5e+156)
   (* (sqrt (* (- im) (/ im re))) 0.5)
   (if (<= re 255000000000.0)
     (* (sqrt (* (+ im re) 2.0)) 0.5)
     (* 0.5 (sqrt (* 4.0 re))))))
double code(double re, double im) {
	double tmp;
	if (re <= -5e+156) {
		tmp = sqrt((-im * (im / re))) * 0.5;
	} else if (re <= 255000000000.0) {
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	} else {
		tmp = 0.5 * sqrt((4.0 * re));
	}
	return tmp;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(re, im)
use fmin_fmax_functions
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= (-5d+156)) then
        tmp = sqrt((-im * (im / re))) * 0.5d0
    else if (re <= 255000000000.0d0) then
        tmp = sqrt(((im + re) * 2.0d0)) * 0.5d0
    else
        tmp = 0.5d0 * sqrt((4.0d0 * re))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= -5e+156) {
		tmp = Math.sqrt((-im * (im / re))) * 0.5;
	} else if (re <= 255000000000.0) {
		tmp = Math.sqrt(((im + re) * 2.0)) * 0.5;
	} else {
		tmp = 0.5 * Math.sqrt((4.0 * re));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= -5e+156:
		tmp = math.sqrt((-im * (im / re))) * 0.5
	elif re <= 255000000000.0:
		tmp = math.sqrt(((im + re) * 2.0)) * 0.5
	else:
		tmp = 0.5 * math.sqrt((4.0 * re))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= -5e+156)
		tmp = Float64(sqrt(Float64(Float64(-im) * Float64(im / re))) * 0.5);
	elseif (re <= 255000000000.0)
		tmp = Float64(sqrt(Float64(Float64(im + re) * 2.0)) * 0.5);
	else
		tmp = Float64(0.5 * sqrt(Float64(4.0 * re)));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= -5e+156)
		tmp = sqrt((-im * (im / re))) * 0.5;
	elseif (re <= 255000000000.0)
		tmp = sqrt(((im + re) * 2.0)) * 0.5;
	else
		tmp = 0.5 * sqrt((4.0 * re));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, -5e+156], N[(N[Sqrt[N[((-im) * N[(im / re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], If[LessEqual[re, 255000000000.0], N[(N[Sqrt[N[(N[(im + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[(0.5 * N[Sqrt[N[(4.0 * re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq -5 \cdot 10^{+156}:\\
\;\;\;\;\sqrt{\left(-im\right) \cdot \frac{im}{re}} \cdot 0.5\\

\mathbf{elif}\;re \leq 255000000000:\\
\;\;\;\;\sqrt{\left(im + re\right) \cdot 2} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -4.99999999999999992e156

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{\color{blue}{re}}} \]
      3. lower-pow.f6415.1

        \[\leadsto 0.5 \cdot \sqrt{-1 \cdot \frac{{im}^{2}}{re}} \]
    4. Applied rewrites15.1%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

        \[\leadsto \color{blue}{\sqrt{-1 \cdot \frac{{im}^{2}}{re}} \cdot \frac{1}{2}} \]
      3. lower-*.f6415.1

        \[\leadsto \color{blue}{\sqrt{-1 \cdot \frac{{im}^{2}}{re}} \cdot 0.5} \]
      4. lift-*.f64N/A

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

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

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

        \[\leadsto \sqrt{\mathsf{neg}\left(\frac{{im}^{2}}{re}\right)} \cdot \frac{1}{2} \]
      8. pow2N/A

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

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

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

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

        \[\leadsto \sqrt{\left(-im\right) \cdot \frac{\color{blue}{im}}{re}} \cdot \frac{1}{2} \]
      13. lower-/.f6418.3

        \[\leadsto \sqrt{\left(-im\right) \cdot \frac{im}{\color{blue}{re}}} \cdot 0.5 \]
    6. Applied rewrites18.3%

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

    if -4.99999999999999992e156 < re < 2.55e11

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \color{blue}{\frac{re}{im}}\right)\right)} \]
      3. lower-/.f6429.9

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{\color{blue}{im}}\right)\right)} \]
    4. Applied rewrites29.9%

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

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

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot \frac{1}{2}} \]
      3. lower-*.f6429.9

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot 0.5} \]
    6. Applied rewrites30.8%

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

    if 2.55e11 < re

    1. Initial program 41.0%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{4 \cdot re}} \]
    3. Step-by-step derivation
      1. lower-*.f6425.7

        \[\leadsto 0.5 \cdot \sqrt{4 \cdot \color{blue}{re}} \]
    4. Applied rewrites25.7%

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

Alternative 5: 42.6% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \leq 0.14:\\ \;\;\;\;\sqrt{im + im} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\ \end{array} \end{array} \]
(FPCore (re im)
 :precision binary64
 (if (<= re 0.14) (* (sqrt (+ im im)) 0.5) (* 0.5 (sqrt (* 4.0 re)))))
double code(double re, double im) {
	double tmp;
	if (re <= 0.14) {
		tmp = sqrt((im + im)) * 0.5;
	} else {
		tmp = 0.5 * sqrt((4.0 * re));
	}
	return tmp;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(re, im)
use fmin_fmax_functions
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (re <= 0.14d0) then
        tmp = sqrt((im + im)) * 0.5d0
    else
        tmp = 0.5d0 * sqrt((4.0d0 * re))
    end if
    code = tmp
end function
public static double code(double re, double im) {
	double tmp;
	if (re <= 0.14) {
		tmp = Math.sqrt((im + im)) * 0.5;
	} else {
		tmp = 0.5 * Math.sqrt((4.0 * re));
	}
	return tmp;
}
def code(re, im):
	tmp = 0
	if re <= 0.14:
		tmp = math.sqrt((im + im)) * 0.5
	else:
		tmp = 0.5 * math.sqrt((4.0 * re))
	return tmp
function code(re, im)
	tmp = 0.0
	if (re <= 0.14)
		tmp = Float64(sqrt(Float64(im + im)) * 0.5);
	else
		tmp = Float64(0.5 * sqrt(Float64(4.0 * re)));
	end
	return tmp
end
function tmp_2 = code(re, im)
	tmp = 0.0;
	if (re <= 0.14)
		tmp = sqrt((im + im)) * 0.5;
	else
		tmp = 0.5 * sqrt((4.0 * re));
	end
	tmp_2 = tmp;
end
code[re_, im_] := If[LessEqual[re, 0.14], N[(N[Sqrt[N[(im + im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision], N[(0.5 * N[Sqrt[N[(4.0 * re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \leq 0.14:\\
\;\;\;\;\sqrt{im + im} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{4 \cdot re}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < 0.14000000000000001

    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \color{blue}{\frac{re}{im}}\right)\right)} \]
      3. lower-/.f6429.9

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{\color{blue}{im}}\right)\right)} \]
    4. Applied rewrites29.9%

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

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

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot \frac{1}{2}} \]
      3. lower-*.f6429.9

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot 0.5} \]
    6. Applied rewrites30.8%

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

      \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
    8. Step-by-step derivation
      1. Applied rewrites27.3%

        \[\leadsto \sqrt{im \cdot 2} \cdot 0.5 \]
      2. Step-by-step derivation
        1. lower-hypot.f64N/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        2. *-rgt-identityN/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        3. *-rgt-identityN/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        4. distribute-rgt-inN/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        5. lift-hypot.f6427.3

          \[\leadsto \sqrt{im \cdot 2} \cdot 0.5 \]
        6. *-lft-identity27.3

          \[\leadsto \sqrt{im \cdot 2} \cdot 0.5 \]
        7. lift-*.f64N/A

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

          \[\leadsto \sqrt{\color{blue}{2 \cdot im}} \cdot \frac{1}{2} \]
        9. count-2-revN/A

          \[\leadsto \sqrt{\color{blue}{im + im}} \cdot \frac{1}{2} \]
        10. lower-+.f6427.3

          \[\leadsto \sqrt{\color{blue}{im + im}} \cdot 0.5 \]
      3. Applied rewrites27.3%

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

      if 0.14000000000000001 < re

      1. Initial program 41.0%

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{4 \cdot re}} \]
      3. Step-by-step derivation
        1. lower-*.f6425.7

          \[\leadsto 0.5 \cdot \sqrt{4 \cdot \color{blue}{re}} \]
      4. Applied rewrites25.7%

        \[\leadsto 0.5 \cdot \sqrt{\color{blue}{4 \cdot re}} \]
    9. Recombined 2 regimes into one program.
    10. Add Preprocessing

    Alternative 6: 27.3% accurate, 2.6× speedup?

    \[\begin{array}{l} \\ \sqrt{im + im} \cdot 0.5 \end{array} \]
    (FPCore (re im) :precision binary64 (* (sqrt (+ im im)) 0.5))
    double code(double re, double im) {
    	return sqrt((im + im)) * 0.5;
    }
    
    module fmin_fmax_functions
        implicit none
        private
        public fmax
        public fmin
    
        interface fmax
            module procedure fmax88
            module procedure fmax44
            module procedure fmax84
            module procedure fmax48
        end interface
        interface fmin
            module procedure fmin88
            module procedure fmin44
            module procedure fmin84
            module procedure fmin48
        end interface
    contains
        real(8) function fmax88(x, y) result (res)
            real(8), intent (in) :: x
            real(8), intent (in) :: y
            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
        end function
        real(4) function fmax44(x, y) result (res)
            real(4), intent (in) :: x
            real(4), intent (in) :: y
            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
        end function
        real(8) function fmax84(x, y) result(res)
            real(8), intent (in) :: x
            real(4), intent (in) :: y
            res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
        end function
        real(8) function fmax48(x, y) result(res)
            real(4), intent (in) :: x
            real(8), intent (in) :: y
            res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
        end function
        real(8) function fmin88(x, y) result (res)
            real(8), intent (in) :: x
            real(8), intent (in) :: y
            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
        end function
        real(4) function fmin44(x, y) result (res)
            real(4), intent (in) :: x
            real(4), intent (in) :: y
            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
        end function
        real(8) function fmin84(x, y) result(res)
            real(8), intent (in) :: x
            real(4), intent (in) :: y
            res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
        end function
        real(8) function fmin48(x, y) result(res)
            real(4), intent (in) :: x
            real(8), intent (in) :: y
            res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
        end function
    end module
    
    real(8) function code(re, im)
    use fmin_fmax_functions
        real(8), intent (in) :: re
        real(8), intent (in) :: im
        code = sqrt((im + im)) * 0.5d0
    end function
    
    public static double code(double re, double im) {
    	return Math.sqrt((im + im)) * 0.5;
    }
    
    def code(re, im):
    	return math.sqrt((im + im)) * 0.5
    
    function code(re, im)
    	return Float64(sqrt(Float64(im + im)) * 0.5)
    end
    
    function tmp = code(re, im)
    	tmp = sqrt((im + im)) * 0.5;
    end
    
    code[re_, im_] := N[(N[Sqrt[N[(im + im), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \sqrt{im + im} \cdot 0.5
    \end{array}
    
    Derivation
    1. Initial program 41.0%

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

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

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

        \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \color{blue}{\frac{re}{im}}\right)\right)} \]
      3. lower-/.f6429.9

        \[\leadsto 0.5 \cdot \sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{\color{blue}{im}}\right)\right)} \]
    4. Applied rewrites29.9%

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

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

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot \frac{1}{2}} \]
      3. lower-*.f6429.9

        \[\leadsto \color{blue}{\sqrt{2 \cdot \left(im \cdot \left(1 + \frac{re}{im}\right)\right)} \cdot 0.5} \]
    6. Applied rewrites30.8%

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

      \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
    8. Step-by-step derivation
      1. Applied rewrites27.3%

        \[\leadsto \sqrt{im \cdot 2} \cdot 0.5 \]
      2. Step-by-step derivation
        1. lower-hypot.f64N/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        2. *-rgt-identityN/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        3. *-rgt-identityN/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        4. distribute-rgt-inN/A

          \[\leadsto \sqrt{im \cdot 2} \cdot \frac{1}{2} \]
        5. lift-hypot.f6427.3

          \[\leadsto \sqrt{im \cdot 2} \cdot 0.5 \]
        6. *-lft-identity27.3

          \[\leadsto \sqrt{im \cdot 2} \cdot 0.5 \]
        7. lift-*.f64N/A

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

          \[\leadsto \sqrt{\color{blue}{2 \cdot im}} \cdot \frac{1}{2} \]
        9. count-2-revN/A

          \[\leadsto \sqrt{\color{blue}{im + im}} \cdot \frac{1}{2} \]
        10. lower-+.f6427.3

          \[\leadsto \sqrt{\color{blue}{im + im}} \cdot 0.5 \]
      3. Applied rewrites27.3%

        \[\leadsto \color{blue}{\sqrt{im + im}} \cdot 0.5 \]
      4. Add Preprocessing

      Developer Target 1: 48.1% 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;
      }
      
      module fmin_fmax_functions
          implicit none
          private
          public fmax
          public fmin
      
          interface fmax
              module procedure fmax88
              module procedure fmax44
              module procedure fmax84
              module procedure fmax48
          end interface
          interface fmin
              module procedure fmin88
              module procedure fmin44
              module procedure fmin84
              module procedure fmin48
          end interface
      contains
          real(8) function fmax88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(4) function fmax44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(8) function fmax84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmax48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
          end function
          real(8) function fmin88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(4) function fmin44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(8) function fmin84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmin48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
          end function
      end module
      
      real(8) function code(re, im)
      use fmin_fmax_functions
          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 2025162 
      (FPCore (re im)
        :name "math.sqrt on complex, real part"
        :precision binary64
      
        :alt
        (! :herbie-platform c (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)))))