Bell 32V development

[unix-history] / usr / src / libF77 / c_sqrt.c

#include "complex"

c_sqrt(r, z)
complex *r, *z;
{
double mag, sqrt(), cabs();

if( (mag = cabs(z->real, z->imag)) == 0.)
       r->real = r->imag = 0.;
else if(z->real > 0)
       {
       r->real = sqrt(0.5 * (mag + z->real) );
       r->imag = z->imag / r->real / 2;
       }
else
       {
       r->imag = sqrt(0.5 * (mag - z->real) );
       if(z->imag < 0)
               r->imag = - r->imag;
       r->real = z->imag / r->imag /2;
       }
}