0.5 \cdot \sqrt{2.0 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\begin{array}{l}
\mathbf{if}\;re \le -1.1092877325715177 \cdot 10^{+151}:\\
\;\;\;\;\sqrt{\left(-2 \cdot re\right) \cdot 2.0} \cdot 0.5\\
\mathbf{elif}\;re \le 8.845630688714825 \cdot 10^{-307}:\\
\;\;\;\;\sqrt{2.0 \cdot \left(\sqrt{\sqrt{im \cdot im + re \cdot re}} \cdot \sqrt{\sqrt{im \cdot im + re \cdot re}} - re\right)} \cdot 0.5\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \frac{\sqrt{\left(im \cdot im\right) \cdot 2.0}}{\sqrt{\sqrt{im \cdot im + re \cdot re} + re}}\\
\end{array}double f(double re, double im) {
double r472082 = 0.5;
double r472083 = 2.0;
double r472084 = re;
double r472085 = r472084 * r472084;
double r472086 = im;
double r472087 = r472086 * r472086;
double r472088 = r472085 + r472087;
double r472089 = sqrt(r472088);
double r472090 = r472089 - r472084;
double r472091 = r472083 * r472090;
double r472092 = sqrt(r472091);
double r472093 = r472082 * r472092;
return r472093;
}
double f(double re, double im) {
double r472094 = re;
double r472095 = -1.1092877325715177e+151;
bool r472096 = r472094 <= r472095;
double r472097 = -2.0;
double r472098 = r472097 * r472094;
double r472099 = 2.0;
double r472100 = r472098 * r472099;
double r472101 = sqrt(r472100);
double r472102 = 0.5;
double r472103 = r472101 * r472102;
double r472104 = 8.845630688714825e-307;
bool r472105 = r472094 <= r472104;
double r472106 = im;
double r472107 = r472106 * r472106;
double r472108 = r472094 * r472094;
double r472109 = r472107 + r472108;
double r472110 = sqrt(r472109);
double r472111 = sqrt(r472110);
double r472112 = r472111 * r472111;
double r472113 = r472112 - r472094;
double r472114 = r472099 * r472113;
double r472115 = sqrt(r472114);
double r472116 = r472115 * r472102;
double r472117 = r472107 * r472099;
double r472118 = sqrt(r472117);
double r472119 = r472110 + r472094;
double r472120 = sqrt(r472119);
double r472121 = r472118 / r472120;
double r472122 = r472102 * r472121;
double r472123 = r472105 ? r472116 : r472122;
double r472124 = r472096 ? r472103 : r472123;
return r472124;
}



Bits error versus re



Bits error versus im
Results
if re < -1.1092877325715177e+151Initial program 60.0
Taylor expanded around inf 60.0
Simplified60.0
rmApplied add-sqr-sqrt60.0
Taylor expanded around -inf 7.1
if -1.1092877325715177e+151 < re < 8.845630688714825e-307Initial program 19.9
Taylor expanded around inf 19.9
Simplified19.9
rmApplied add-sqr-sqrt20.0
if 8.845630688714825e-307 < re Initial program 44.9
rmApplied flip--44.8
Applied associate-*r/44.8
Applied sqrt-div44.9
Simplified33.9
Final simplification25.2
herbie shell --seed 2019141
(FPCore (re im)
:name "math.sqrt on complex, imaginary part, im greater than 0 branch"
(* 0.5 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))