r->i = atan2(z->i, z->r); r->r = log( f__cabs(z->r, z->i) );
complex res;  res.i = atan2(z->i, z->r); res.r = log( f__cabs(z->r, z->i) );  resx->r = res.r; resx->i = res.i;
void c_log(complex *r, complex *z)#endif{r->i = atan2(z->i, z->r);r->r = log( f__cabs(z->r, z->i) );}