0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\begin{array}{l}
\mathbf{if}\;re \le -4.2696195727379345 \cdot 10^{139}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(-2 \cdot re\right)}\\
\mathbf{elif}\;re \le -3.87971466314923503 \cdot 10^{-161}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{1} \cdot \sqrt{re \cdot re + im \cdot im} - re\right)}\\
\mathbf{elif}\;re \le 3.06622232904101925 \cdot 10^{-255}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(im - re\right)}\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \frac{\sqrt{{im}^{2} \cdot 2}}{\sqrt{\sqrt{re \cdot re + im \cdot im} + re}}\\
\end{array}double f(double re, double im) {
double r79770 = 0.5;
double r79771 = 2.0;
double r79772 = re;
double r79773 = r79772 * r79772;
double r79774 = im;
double r79775 = r79774 * r79774;
double r79776 = r79773 + r79775;
double r79777 = sqrt(r79776);
double r79778 = r79777 - r79772;
double r79779 = r79771 * r79778;
double r79780 = sqrt(r79779);
double r79781 = r79770 * r79780;
return r79781;
}
double f(double re, double im) {
double r79782 = re;
double r79783 = -4.2696195727379345e+139;
bool r79784 = r79782 <= r79783;
double r79785 = 0.5;
double r79786 = 2.0;
double r79787 = -2.0;
double r79788 = r79787 * r79782;
double r79789 = r79786 * r79788;
double r79790 = sqrt(r79789);
double r79791 = r79785 * r79790;
double r79792 = -3.879714663149235e-161;
bool r79793 = r79782 <= r79792;
double r79794 = 1.0;
double r79795 = sqrt(r79794);
double r79796 = r79782 * r79782;
double r79797 = im;
double r79798 = r79797 * r79797;
double r79799 = r79796 + r79798;
double r79800 = sqrt(r79799);
double r79801 = r79795 * r79800;
double r79802 = r79801 - r79782;
double r79803 = r79786 * r79802;
double r79804 = sqrt(r79803);
double r79805 = r79785 * r79804;
double r79806 = 3.0662223290410192e-255;
bool r79807 = r79782 <= r79806;
double r79808 = r79797 - r79782;
double r79809 = r79786 * r79808;
double r79810 = sqrt(r79809);
double r79811 = r79785 * r79810;
double r79812 = 2.0;
double r79813 = pow(r79797, r79812);
double r79814 = r79813 * r79786;
double r79815 = sqrt(r79814);
double r79816 = r79800 + r79782;
double r79817 = sqrt(r79816);
double r79818 = r79815 / r79817;
double r79819 = r79785 * r79818;
double r79820 = r79807 ? r79811 : r79819;
double r79821 = r79793 ? r79805 : r79820;
double r79822 = r79784 ? r79791 : r79821;
return r79822;
}



Bits error versus re



Bits error versus im
Results
if re < -4.2696195727379345e+139Initial program 59.5
Taylor expanded around -inf 8.4
if -4.2696195727379345e+139 < re < -3.879714663149235e-161Initial program 16.9
rmApplied add-sqr-sqrt16.9
Applied sqrt-prod17.0
rmApplied *-un-lft-identity17.0
Applied sqrt-prod17.0
Applied associate-*l*17.0
Simplified16.9
if -3.879714663149235e-161 < re < 3.0662223290410192e-255Initial program 31.3
rmApplied add-sqr-sqrt31.3
Applied sqrt-prod31.4
rmApplied add-sqr-sqrt31.4
Applied sqrt-prod31.4
Applied sqrt-prod31.5
Applied associate-*r*31.4
Simplified31.5
Taylor expanded around 0 33.3
if 3.0662223290410192e-255 < re Initial program 47.7
rmApplied flip--47.6
Applied associate-*r/47.6
Applied sqrt-div47.7
Simplified36.2
Final simplification27.2
herbie shell --seed 2020047
(FPCore (re im)
:name "math.sqrt on complex, imaginary part, im greater than 0 branch"
:precision binary64
(* 0.5 (sqrt (* 2 (- (sqrt (+ (* re re) (* im im))) re)))))