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 #ifdef IEEE_COMPLEX_DIVIDE
  23                         float af, bf;
  24                         af = bf = abr;
  25                         if (a->i != 0 || a->r != 0)
  26                                 af = 1.;
  27                         c->i = c->r = af / bf;
  28                         return;
  29 #else
  30                         sig_die("complex division by zero", 1);
  31 #endif
  32                         }
  33                 ratio = (double)b->r / b->i ;
  34                 den = b->i * (1 + ratio*ratio);
  35                 cr = (a->r*ratio + a->i) / den;
  36                 c->i = (a->i*ratio - a->r) / den;
  37                 }
  38
  39         else
  40                 {
  41                 ratio = (double)b->i / b->r ;
  42                 den = b->r * (1 + ratio*ratio);
  43                 cr = (a->r + a->i*ratio) / den;
  44                 c->i = (a->i - a->r*ratio) / den;
  45                 }
  46         c->r = cr;
  47         }