0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\begin{array}{l}
\mathbf{if}\;re \le -7.43908969742662921 \cdot 10^{84}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(-1 \cdot re - re\right)}\\
\mathbf{elif}\;re \le -2.0006798653343339 \cdot 10^{-304}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{\sqrt{re \cdot re + im \cdot im}} \cdot \sqrt{\sqrt{re \cdot re + im \cdot im}} - re\right)}\\
\mathbf{elif}\;re \le 1.52111731254879352 \cdot 10^{149}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\left|im\right| \cdot \frac{\left|im\right|}{re + \sqrt{re \cdot re + im \cdot im}}\right)}\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \frac{im \cdot im + 0}{2 \cdot re}}\\
\end{array}double f(double re, double im) {
double r16278 = 0.5;
double r16279 = 2.0;
double r16280 = re;
double r16281 = r16280 * r16280;
double r16282 = im;
double r16283 = r16282 * r16282;
double r16284 = r16281 + r16283;
double r16285 = sqrt(r16284);
double r16286 = r16285 - r16280;
double r16287 = r16279 * r16286;
double r16288 = sqrt(r16287);
double r16289 = r16278 * r16288;
return r16289;
}
double f(double re, double im) {
double r16290 = re;
double r16291 = -7.439089697426629e+84;
bool r16292 = r16290 <= r16291;
double r16293 = 0.5;
double r16294 = 2.0;
double r16295 = -1.0;
double r16296 = r16295 * r16290;
double r16297 = r16296 - r16290;
double r16298 = r16294 * r16297;
double r16299 = sqrt(r16298);
double r16300 = r16293 * r16299;
double r16301 = -2.000679865334334e-304;
bool r16302 = r16290 <= r16301;
double r16303 = r16290 * r16290;
double r16304 = im;
double r16305 = r16304 * r16304;
double r16306 = r16303 + r16305;
double r16307 = sqrt(r16306);
double r16308 = sqrt(r16307);
double r16309 = r16308 * r16308;
double r16310 = r16309 - r16290;
double r16311 = r16294 * r16310;
double r16312 = sqrt(r16311);
double r16313 = r16293 * r16312;
double r16314 = 1.5211173125487935e+149;
bool r16315 = r16290 <= r16314;
double r16316 = fabs(r16304);
double r16317 = r16290 + r16307;
double r16318 = r16316 / r16317;
double r16319 = r16316 * r16318;
double r16320 = r16294 * r16319;
double r16321 = sqrt(r16320);
double r16322 = r16293 * r16321;
double r16323 = 0.0;
double r16324 = r16305 + r16323;
double r16325 = 2.0;
double r16326 = r16325 * r16290;
double r16327 = r16324 / r16326;
double r16328 = r16294 * r16327;
double r16329 = sqrt(r16328);
double r16330 = r16293 * r16329;
double r16331 = r16315 ? r16322 : r16330;
double r16332 = r16302 ? r16313 : r16331;
double r16333 = r16292 ? r16300 : r16332;
return r16333;
}



Bits error versus re



Bits error versus im
Results
if re < -7.439089697426629e+84Initial program 48.4
Taylor expanded around -inf 10.7
if -7.439089697426629e+84 < re < -2.000679865334334e-304Initial program 21.0
rmApplied add-sqr-sqrt21.0
Applied sqrt-prod21.1
if -2.000679865334334e-304 < re < 1.5211173125487935e+149Initial program 39.6
rmApplied add-sqr-sqrt39.6
Applied sqrt-prod40.6
rmApplied flip--40.4
Simplified30.5
Simplified30.4
rmApplied *-un-lft-identity30.4
Applied add-sqr-sqrt30.4
Applied times-frac30.4
Simplified30.3
Simplified28.6
if 1.5211173125487935e+149 < re Initial program 63.7
rmApplied add-sqr-sqrt63.7
Applied sqrt-prod63.7
rmApplied flip--63.8
Simplified50.0
Simplified50.0
Taylor expanded around inf 31.6
Final simplification23.4
herbie shell --seed 2020003
(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)))))