f2c libF77 from netlib.att.com Jan 4 1994

[unix-history] / lib / libF77 / z_div.c

#include "f2c.h"

#ifdef KR_headers
extern void sig_die();
VOID z_div(c, a, b) doublecomplex *a, *b, *c;
#else
extern void sig_die(char*, int);
void z_div(doublecomplex *c, doublecomplex *a, doublecomplex *b)
#endif
{
double ratio, den;
double abr, abi;

if( (abr = b->r) < 0.)
       abr = - abr;
if( (abi = b->i) < 0.)
       abi = - abi;
if( abr <= abi )
       {
       if(abi == 0)
               sig_die("complex division by zero", 1);
       ratio = b->r / b->i ;
       den = b->i * (1 + ratio*ratio);
       c->r = (a->r*ratio + a->i) / den;
       c->i = (a->i*ratio - a->r) / den;
       }

else
       {
       ratio = b->i / b->r ;
       den = b->r * (1 + ratio*ratio);
       c->r = (a->r + a->i*ratio) / den;
       c->i = (a->i - a->r*ratio) / den;
       }

}