libf2c/libF77/c_div.c

   1 #include "f2c.h"
   2
   3 #ifdef KR_headers
   4 extern VOID sig_die();
   5 VOID c_div(c, a, b)
   6 complex *a, *b, *c;
   7 #else
   8 extern void sig_die(char*,int);
   9 void c_div(complex *c, complex *a, complex *b)
  10 #endif
  11 {
  12         double ratio, den;
  13         double abr, abi, cr;
  14
  15         if( (abr = b->r) < 0.)
  16                 abr = - abr;
  17         if( (abi = b->i) < 0.)
  18                 abi = - abi;
  19         if( abr <= abi )
  20                 {
  21                 if(abi == 0)
  22                         sig_die("complex division by zero", 1);
  23                 ratio = (double)b->r / b->i ;
  24                 den = b->i * (1 + ratio*ratio);
  25                 cr = (a->r*ratio + a->i) / den;
  26                 c->i = (a->i*ratio - a->r) / den;
  27                 }
  28
  29         else
  30                 {
  31                 ratio = (double)b->i / b->r ;
  32                 den = b->r * (1 + ratio*ratio);
  33                 cr = (a->r + a->i*ratio) / den;
  34                 c->i = (a->i - a->r*ratio) / den;
  35                 }
  36         c->r = cr;
  37         }