libf2c/libF77/c_div.c

   1 #include "f2c.h"
   2
   3 #ifdef KR_headers
   4 extern VOID sig_die();
   5 VOID c_div(resx, a, b)
   6 complex *a, *b, *resx;
   7 #else
   8 extern void sig_die(char*,int);
   9 void c_div(complex *resx, complex *a, complex *b)
  10 #endif
  11 {
  12 double ratio, den;
  13 double abr, abi;
  14 complex res;
  15
  16 if( (abr = b->r) < 0.)
  17         abr = - abr;
  18 if( (abi = b->i) < 0.)
  19         abi = - abi;
  20 if( abr <= abi )
  21         {
  22         if(abi == 0)
  23                 sig_die("complex division by zero", 1);
  24         ratio = (double)b->r / b->i ;
  25         den = b->i * (1 + ratio*ratio);
  26         res.r = (a->r*ratio + a->i) / den;
  27         res.i = (a->i*ratio - a->r) / den;
  28         }
  29
  30 else
  31         {
  32         ratio = (double)b->i / b->r ;
  33         den = b->r * (1 + ratio*ratio);
  34         res.r = (a->r + a->i*ratio) / den;
  35         res.i = (a->i - a->r*ratio) / den;
  36         }
  37
  38 resx->r = res.r;
  39 resx->i = res.i;
  40 }