\log \left(\sqrt{re \cdot re + im \cdot im}\right)\begin{array}{l}
\mathbf{if}\;re \le -9.68163596973405975259895298385316105053 \cdot 10^{102}:\\
\;\;\;\;\log \left(-re\right)\\
\mathbf{elif}\;re \le 3.545380571942664302984715356869784321431 \cdot 10^{140}:\\
\;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\
\mathbf{else}:\\
\;\;\;\;\log re\\
\end{array}double f(double re, double im) {
double r2141995 = re;
double r2141996 = r2141995 * r2141995;
double r2141997 = im;
double r2141998 = r2141997 * r2141997;
double r2141999 = r2141996 + r2141998;
double r2142000 = sqrt(r2141999);
double r2142001 = log(r2142000);
return r2142001;
}
double f(double re, double im) {
double r2142002 = re;
double r2142003 = -9.68163596973406e+102;
bool r2142004 = r2142002 <= r2142003;
double r2142005 = -r2142002;
double r2142006 = log(r2142005);
double r2142007 = 3.5453805719426643e+140;
bool r2142008 = r2142002 <= r2142007;
double r2142009 = im;
double r2142010 = r2142009 * r2142009;
double r2142011 = r2142002 * r2142002;
double r2142012 = r2142010 + r2142011;
double r2142013 = sqrt(r2142012);
double r2142014 = log(r2142013);
double r2142015 = log(r2142002);
double r2142016 = r2142008 ? r2142014 : r2142015;
double r2142017 = r2142004 ? r2142006 : r2142016;
return r2142017;
}



Bits error versus re



Bits error versus im
Results
if re < -9.68163596973406e+102Initial program 51.9
Taylor expanded around -inf 8.5
Simplified8.5
if -9.68163596973406e+102 < re < 3.5453805719426643e+140Initial program 21.0
if 3.5453805719426643e+140 < re Initial program 59.5
Taylor expanded around inf 7.5
Final simplification17.1
herbie shell --seed 2019172
(FPCore (re im)
:name "math.log/1 on complex, real part"
(log (sqrt (+ (* re re) (* im im)))))