math.sqrt on complex, real part

Percentage Accurate: 41.3% → 88.8%
Time: 4.7s
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: 41.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \end{array} \]
(FPCore (re im)
 :precision binary64
 (* 0.5 (sqrt (* 2.0 (+ (sqrt (+ (* re re) (* im im))) re)))))
double code(double re, double im) {
	return 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im * im))) + re)));
}
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: 88.8% accurate, 0.1× speedup?

\[\begin{array}{l} im_m = \left|im\right| \\ \begin{array}{l} \mathbf{if}\;2 \cdot \left(\sqrt{re \cdot re + im\_m \cdot im\_m} + re\right) \leq 0:\\ \;\;\;\;0.5 \cdot e^{\mathsf{fma}\left(2, \log im\_m, \log \left(\frac{-1}{re}\right)\right) \cdot 0.5}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\left(\mathsf{hypot}\left(im\_m, re\right) + re\right) \cdot 2} \cdot 0.5\\ \end{array} \end{array} \]
im_m = (fabs.f64 im)
(FPCore (re im_m)
 :precision binary64
 (if (<= (* 2.0 (+ (sqrt (+ (* re re) (* im_m im_m))) re)) 0.0)
   (* 0.5 (exp (* (fma 2.0 (log im_m) (log (/ -1.0 re))) 0.5)))
   (* (sqrt (* (+ (hypot im_m re) re) 2.0)) 0.5)))
im_m = fabs(im);
double code(double re, double im_m) {
	double tmp;
	if ((2.0 * (sqrt(((re * re) + (im_m * im_m))) + re)) <= 0.0) {
		tmp = 0.5 * exp((fma(2.0, log(im_m), log((-1.0 / re))) * 0.5));
	} else {
		tmp = sqrt(((hypot(im_m, re) + re) * 2.0)) * 0.5;
	}
	return tmp;
}
im_m = abs(im)
function code(re, im_m)
	tmp = 0.0
	if (Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im_m * im_m))) + re)) <= 0.0)
		tmp = Float64(0.5 * exp(Float64(fma(2.0, log(im_m), log(Float64(-1.0 / re))) * 0.5)));
	else
		tmp = Float64(sqrt(Float64(Float64(hypot(im_m, re) + re) * 2.0)) * 0.5);
	end
	return tmp
end
im_m = N[Abs[im], $MachinePrecision]
code[re_, im$95$m_] := If[LessEqual[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im$95$m * im$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision]), $MachinePrecision], 0.0], N[(0.5 * N[Exp[N[(N[(2.0 * N[Log[im$95$m], $MachinePrecision] + N[Log[N[(-1.0 / re), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[N[(N[(N[Sqrt[im$95$m ^ 2 + re ^ 2], $MachinePrecision] + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}
im_m = \left|im\right|

\\
\begin{array}{l}
\mathbf{if}\;2 \cdot \left(\sqrt{re \cdot re + im\_m \cdot im\_m} + re\right) \leq 0:\\
\;\;\;\;0.5 \cdot e^{\mathsf{fma}\left(2, \log im\_m, \log \left(\frac{-1}{re}\right)\right) \cdot 0.5}\\

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


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

    1. Initial program 7.0%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. Applied rewrites18.5%

      \[\leadsto 0.5 \cdot \color{blue}{e^{\log \left(\left(\mathsf{hypot}\left(im, re\right) + re\right) \cdot 2\right) \cdot 0.5}} \]
    3. Taylor expanded in re around -inf

      \[\leadsto \frac{1}{2} \cdot e^{\color{blue}{\left(\log \left(\frac{-1}{re}\right) + \log \left({im}^{2}\right)\right)} \cdot \frac{1}{2}} \]
    4. Applied rewrites81.0%

      \[\leadsto 0.5 \cdot e^{\color{blue}{\mathsf{fma}\left(2, \log im, \log \left(\frac{-1}{re}\right)\right)} \cdot 0.5} \]

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

    1. Initial program 47.4%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. 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: 85.5% accurate, 0.3× speedup?

\[\begin{array}{l} im_m = \left|im\right| \\ \begin{array}{l} \mathbf{if}\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im\_m \cdot im\_m} + re\right)} \leq 0:\\ \;\;\;\;0.5 \cdot \sqrt{-im\_m \cdot \frac{im\_m}{re}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\left(\mathsf{hypot}\left(im\_m, re\right) + re\right) \cdot 2} \cdot 0.5\\ \end{array} \end{array} \]
im_m = (fabs.f64 im)
(FPCore (re im_m)
 :precision binary64
 (if (<= (* 0.5 (sqrt (* 2.0 (+ (sqrt (+ (* re re) (* im_m im_m))) re)))) 0.0)
   (* 0.5 (sqrt (- (* im_m (/ im_m re)))))
   (* (sqrt (* (+ (hypot im_m re) re) 2.0)) 0.5)))
im_m = fabs(im);
double code(double re, double im_m) {
	double tmp;
	if ((0.5 * sqrt((2.0 * (sqrt(((re * re) + (im_m * im_m))) + re)))) <= 0.0) {
		tmp = 0.5 * sqrt(-(im_m * (im_m / re)));
	} else {
		tmp = sqrt(((hypot(im_m, re) + re) * 2.0)) * 0.5;
	}
	return tmp;
}
im_m = Math.abs(im);
public static double code(double re, double im_m) {
	double tmp;
	if ((0.5 * Math.sqrt((2.0 * (Math.sqrt(((re * re) + (im_m * im_m))) + re)))) <= 0.0) {
		tmp = 0.5 * Math.sqrt(-(im_m * (im_m / re)));
	} else {
		tmp = Math.sqrt(((Math.hypot(im_m, re) + re) * 2.0)) * 0.5;
	}
	return tmp;
}
im_m = math.fabs(im)
def code(re, im_m):
	tmp = 0
	if (0.5 * math.sqrt((2.0 * (math.sqrt(((re * re) + (im_m * im_m))) + re)))) <= 0.0:
		tmp = 0.5 * math.sqrt(-(im_m * (im_m / re)))
	else:
		tmp = math.sqrt(((math.hypot(im_m, re) + re) * 2.0)) * 0.5
	return tmp
im_m = abs(im)
function code(re, im_m)
	tmp = 0.0
	if (Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im_m * im_m))) + re)))) <= 0.0)
		tmp = Float64(0.5 * sqrt(Float64(-Float64(im_m * Float64(im_m / re)))));
	else
		tmp = Float64(sqrt(Float64(Float64(hypot(im_m, re) + re) * 2.0)) * 0.5);
	end
	return tmp
end
im_m = abs(im);
function tmp_2 = code(re, im_m)
	tmp = 0.0;
	if ((0.5 * sqrt((2.0 * (sqrt(((re * re) + (im_m * im_m))) + re)))) <= 0.0)
		tmp = 0.5 * sqrt(-(im_m * (im_m / re)));
	else
		tmp = sqrt(((hypot(im_m, re) + re) * 2.0)) * 0.5;
	end
	tmp_2 = tmp;
end
im_m = N[Abs[im], $MachinePrecision]
code[re_, im$95$m_] := If[LessEqual[N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im$95$m * im$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 0.0], N[(0.5 * N[Sqrt[(-N[(im$95$m * N[(im$95$m / re), $MachinePrecision]), $MachinePrecision])], $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[N[(N[(N[Sqrt[im$95$m ^ 2 + re ^ 2], $MachinePrecision] + re), $MachinePrecision] * 2.0), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}
im_m = \left|im\right|

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

\mathbf{else}:\\
\;\;\;\;\sqrt{\left(\mathsf{hypot}\left(im\_m, re\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 8.9%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    3. Applied rewrites52.0%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-\frac{im \cdot im}{re}}} \]
    4. Applied rewrites59.4%

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

    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 45.6%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. Applied rewrites89.0%

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

Alternative 3: 71.1% accurate, 0.3× speedup?

\[\begin{array}{l} im_m = \left|im\right| \\ \begin{array}{l} t_0 := 0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im\_m \cdot im\_m} + re\right)}\\ \mathbf{if}\;t\_0 \leq 0:\\ \;\;\;\;0.5 \cdot \sqrt{-im\_m \cdot \frac{im\_m}{re}}\\ \mathbf{elif}\;t\_0 \leq 4 \cdot 10^{+71}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im\_m \cdot im\_m\right)} + re\right)}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im\_m + re\right)}\\ \end{array} \end{array} \]
im_m = (fabs.f64 im)
(FPCore (re im_m)
 :precision binary64
 (let* ((t_0 (* 0.5 (sqrt (* 2.0 (+ (sqrt (+ (* re re) (* im_m im_m))) re))))))
   (if (<= t_0 0.0)
     (* 0.5 (sqrt (- (* im_m (/ im_m re)))))
     (if (<= t_0 4e+71)
       (* 0.5 (sqrt (* 2.0 (+ (sqrt (fma re re (* im_m im_m))) re))))
       (* 0.5 (sqrt (* 2.0 (+ im_m re))))))))
im_m = fabs(im);
double code(double re, double im_m) {
	double t_0 = 0.5 * sqrt((2.0 * (sqrt(((re * re) + (im_m * im_m))) + re)));
	double tmp;
	if (t_0 <= 0.0) {
		tmp = 0.5 * sqrt(-(im_m * (im_m / re)));
	} else if (t_0 <= 4e+71) {
		tmp = 0.5 * sqrt((2.0 * (sqrt(fma(re, re, (im_m * im_m))) + re)));
	} else {
		tmp = 0.5 * sqrt((2.0 * (im_m + re)));
	}
	return tmp;
}
im_m = abs(im)
function code(re, im_m)
	t_0 = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(Float64(Float64(re * re) + Float64(im_m * im_m))) + re))))
	tmp = 0.0
	if (t_0 <= 0.0)
		tmp = Float64(0.5 * sqrt(Float64(-Float64(im_m * Float64(im_m / re)))));
	elseif (t_0 <= 4e+71)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(sqrt(fma(re, re, Float64(im_m * im_m))) + re))));
	else
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im_m + re))));
	end
	return tmp
end
im_m = N[Abs[im], $MachinePrecision]
code[re_, im$95$m_] := Block[{t$95$0 = N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(N[(re * re), $MachinePrecision] + N[(im$95$m * im$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, 0.0], N[(0.5 * N[Sqrt[(-N[(im$95$m * N[(im$95$m / re), $MachinePrecision]), $MachinePrecision])], $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$0, 4e+71], N[(0.5 * N[Sqrt[N[(2.0 * N[(N[Sqrt[N[(re * re + N[(im$95$m * im$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(2.0 * N[(im$95$m + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}
im_m = \left|im\right|

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

\mathbf{elif}\;t\_0 \leq 4 \cdot 10^{+71}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\mathsf{fma}\left(re, re, im\_m \cdot im\_m\right)} + re\right)}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 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 8.9%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    3. Applied rewrites52.0%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-\frac{im \cdot im}{re}}} \]
    4. Applied rewrites59.4%

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

    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)))) < 4.0000000000000002e71

    1. Initial program 93.0%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. Applied rewrites93.0%

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

    if 4.0000000000000002e71 < (*.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 7.4%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\color{blue}{im} + re\right)} \]
    3. Applied rewrites56.3%

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

Alternative 4: 68.0% accurate, 1.2× speedup?

\[\begin{array}{l} im_m = \left|im\right| \\ \begin{array}{l} \mathbf{if}\;re \leq -5.6 \cdot 10^{-85}:\\ \;\;\;\;0.5 \cdot \sqrt{-im\_m \cdot \frac{im\_m}{re}}\\ \mathbf{elif}\;re \leq 1.4 \cdot 10^{+64}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im\_m + re\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
im_m = (fabs.f64 im)
(FPCore (re im_m)
 :precision binary64
 (if (<= re -5.6e-85)
   (* 0.5 (sqrt (- (* im_m (/ im_m re)))))
   (if (<= re 1.4e+64) (* 0.5 (sqrt (* 2.0 (+ im_m re)))) (sqrt re))))
im_m = fabs(im);
double code(double re, double im_m) {
	double tmp;
	if (re <= -5.6e-85) {
		tmp = 0.5 * sqrt(-(im_m * (im_m / re)));
	} else if (re <= 1.4e+64) {
		tmp = 0.5 * sqrt((2.0 * (im_m + re)));
	} else {
		tmp = sqrt(re);
	}
	return tmp;
}
im_m =     private
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_m)
use fmin_fmax_functions
    real(8), intent (in) :: re
    real(8), intent (in) :: im_m
    real(8) :: tmp
    if (re <= (-5.6d-85)) then
        tmp = 0.5d0 * sqrt(-(im_m * (im_m / re)))
    else if (re <= 1.4d+64) then
        tmp = 0.5d0 * sqrt((2.0d0 * (im_m + re)))
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
im_m = Math.abs(im);
public static double code(double re, double im_m) {
	double tmp;
	if (re <= -5.6e-85) {
		tmp = 0.5 * Math.sqrt(-(im_m * (im_m / re)));
	} else if (re <= 1.4e+64) {
		tmp = 0.5 * Math.sqrt((2.0 * (im_m + re)));
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
im_m = math.fabs(im)
def code(re, im_m):
	tmp = 0
	if re <= -5.6e-85:
		tmp = 0.5 * math.sqrt(-(im_m * (im_m / re)))
	elif re <= 1.4e+64:
		tmp = 0.5 * math.sqrt((2.0 * (im_m + re)))
	else:
		tmp = math.sqrt(re)
	return tmp
im_m = abs(im)
function code(re, im_m)
	tmp = 0.0
	if (re <= -5.6e-85)
		tmp = Float64(0.5 * sqrt(Float64(-Float64(im_m * Float64(im_m / re)))));
	elseif (re <= 1.4e+64)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * Float64(im_m + re))));
	else
		tmp = sqrt(re);
	end
	return tmp
end
im_m = abs(im);
function tmp_2 = code(re, im_m)
	tmp = 0.0;
	if (re <= -5.6e-85)
		tmp = 0.5 * sqrt(-(im_m * (im_m / re)));
	elseif (re <= 1.4e+64)
		tmp = 0.5 * sqrt((2.0 * (im_m + re)));
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
im_m = N[Abs[im], $MachinePrecision]
code[re_, im$95$m_] := If[LessEqual[re, -5.6e-85], N[(0.5 * N[Sqrt[(-N[(im$95$m * N[(im$95$m / re), $MachinePrecision]), $MachinePrecision])], $MachinePrecision]), $MachinePrecision], If[LessEqual[re, 1.4e+64], N[(0.5 * N[Sqrt[N[(2.0 * N[(im$95$m + re), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]]
\begin{array}{l}
im_m = \left|im\right|

\\
\begin{array}{l}
\mathbf{if}\;re \leq -5.6 \cdot 10^{-85}:\\
\;\;\;\;0.5 \cdot \sqrt{-im\_m \cdot \frac{im\_m}{re}}\\

\mathbf{elif}\;re \leq 1.4 \cdot 10^{+64}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im\_m + re\right)}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if re < -5.60000000000000033e-85

    1. Initial program 17.1%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{\color{blue}{-1 \cdot \frac{{im}^{2}}{re}}} \]
    3. Applied rewrites40.1%

      \[\leadsto 0.5 \cdot \sqrt{\color{blue}{-\frac{im \cdot im}{re}}} \]
    4. Applied rewrites45.5%

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

    if -5.60000000000000033e-85 < re < 1.40000000000000012e64

    1. Initial program 60.6%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \left(\color{blue}{im} + re\right)} \]
    3. Applied rewrites77.3%

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

    if 1.40000000000000012e64 < re

    1. Initial program 31.8%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. Applied rewrites31.2%

      \[\leadsto \color{blue}{\left(\sqrt{0.5} \cdot \sqrt{0.5}\right)} \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    3. Applied rewrites31.0%

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

      \[\leadsto \color{blue}{\sqrt{re} \cdot \left({\left(\sqrt{\frac{1}{2}}\right)}^{2} \cdot {\left(\sqrt{2}\right)}^{2}\right)} \]
    5. Applied rewrites81.9%

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

Alternative 5: 64.8% accurate, 1.7× speedup?

\[\begin{array}{l} im_m = \left|im\right| \\ \begin{array}{l} \mathbf{if}\;re \leq 4.1 \cdot 10^{-67}:\\ \;\;\;\;0.5 \cdot \sqrt{2 \cdot im\_m}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{re}\\ \end{array} \end{array} \]
im_m = (fabs.f64 im)
(FPCore (re im_m)
 :precision binary64
 (if (<= re 4.1e-67) (* 0.5 (sqrt (* 2.0 im_m))) (sqrt re)))
im_m = fabs(im);
double code(double re, double im_m) {
	double tmp;
	if (re <= 4.1e-67) {
		tmp = 0.5 * sqrt((2.0 * im_m));
	} else {
		tmp = sqrt(re);
	}
	return tmp;
}
im_m =     private
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_m)
use fmin_fmax_functions
    real(8), intent (in) :: re
    real(8), intent (in) :: im_m
    real(8) :: tmp
    if (re <= 4.1d-67) then
        tmp = 0.5d0 * sqrt((2.0d0 * im_m))
    else
        tmp = sqrt(re)
    end if
    code = tmp
end function
im_m = Math.abs(im);
public static double code(double re, double im_m) {
	double tmp;
	if (re <= 4.1e-67) {
		tmp = 0.5 * Math.sqrt((2.0 * im_m));
	} else {
		tmp = Math.sqrt(re);
	}
	return tmp;
}
im_m = math.fabs(im)
def code(re, im_m):
	tmp = 0
	if re <= 4.1e-67:
		tmp = 0.5 * math.sqrt((2.0 * im_m))
	else:
		tmp = math.sqrt(re)
	return tmp
im_m = abs(im)
function code(re, im_m)
	tmp = 0.0
	if (re <= 4.1e-67)
		tmp = Float64(0.5 * sqrt(Float64(2.0 * im_m)));
	else
		tmp = sqrt(re);
	end
	return tmp
end
im_m = abs(im);
function tmp_2 = code(re, im_m)
	tmp = 0.0;
	if (re <= 4.1e-67)
		tmp = 0.5 * sqrt((2.0 * im_m));
	else
		tmp = sqrt(re);
	end
	tmp_2 = tmp;
end
im_m = N[Abs[im], $MachinePrecision]
code[re_, im$95$m_] := If[LessEqual[re, 4.1e-67], N[(0.5 * N[Sqrt[N[(2.0 * im$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[re], $MachinePrecision]]
\begin{array}{l}
im_m = \left|im\right|

\\
\begin{array}{l}
\mathbf{if}\;re \leq 4.1 \cdot 10^{-67}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot im\_m}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if re < 4.0999999999999997e-67

    1. Initial program 38.6%

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

      \[\leadsto \frac{1}{2} \cdot \sqrt{2 \cdot \color{blue}{im}} \]
    3. Applied rewrites61.6%

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

    if 4.0999999999999997e-67 < re

    1. Initial program 47.6%

      \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    2. Applied rewrites46.8%

      \[\leadsto \color{blue}{\left(\sqrt{0.5} \cdot \sqrt{0.5}\right)} \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
    3. Applied rewrites46.5%

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

      \[\leadsto \color{blue}{\sqrt{re} \cdot \left({\left(\sqrt{\frac{1}{2}}\right)}^{2} \cdot {\left(\sqrt{2}\right)}^{2}\right)} \]
    5. Applied rewrites72.2%

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

Alternative 6: 25.8% accurate, 4.3× speedup?

\[\begin{array}{l} im_m = \left|im\right| \\ \sqrt{re} \end{array} \]
im_m = (fabs.f64 im)
(FPCore (re im_m) :precision binary64 (sqrt re))
im_m = fabs(im);
double code(double re, double im_m) {
	return sqrt(re);
}
im_m =     private
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_m)
use fmin_fmax_functions
    real(8), intent (in) :: re
    real(8), intent (in) :: im_m
    code = sqrt(re)
end function
im_m = Math.abs(im);
public static double code(double re, double im_m) {
	return Math.sqrt(re);
}
im_m = math.fabs(im)
def code(re, im_m):
	return math.sqrt(re)
im_m = abs(im)
function code(re, im_m)
	return sqrt(re)
end
im_m = abs(im);
function tmp = code(re, im_m)
	tmp = sqrt(re);
end
im_m = N[Abs[im], $MachinePrecision]
code[re_, im$95$m_] := N[Sqrt[re], $MachinePrecision]
\begin{array}{l}
im_m = \left|im\right|

\\
\sqrt{re}
\end{array}
Derivation
  1. Initial program 41.3%

    \[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
  2. Applied rewrites40.6%

    \[\leadsto \color{blue}{\left(\sqrt{0.5} \cdot \sqrt{0.5}\right)} \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} + re\right)} \]
  3. Applied rewrites40.3%

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

    \[\leadsto \color{blue}{\sqrt{re} \cdot \left({\left(\sqrt{\frac{1}{2}}\right)}^{2} \cdot {\left(\sqrt{2}\right)}^{2}\right)} \]
  5. Applied rewrites25.8%

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

Developer Target 1: 48.5% 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 2025106 
(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)))))