libf2c/libF77/z_div.c

   1 #include "f2c.h"
   2
   3 extern void sig_die (char *, int);
   4 void
   5 z_div (doublecomplex * c, doublecomplex * a, doublecomplex * b)
   6 {
   7   double ratio, den;
   8   double abr, abi, cr;
   9
  10   if ((abr = b->r) < 0.)
  11     abr = -abr;
  12   if ((abi = b->i) < 0.)
  13     abi = -abi;
  14   if (abr <= abi)
  15     {
  16       if (abi == 0)
  17         {
  18 #ifdef IEEE_COMPLEX_DIVIDE
  19           if (a->i != 0 || a->r != 0)
  20             abi = 1.;
  21           c->i = c->r = abi / abr;
  22           return;
  23 #else
  24           sig_die ("complex division by zero", 1);
  25 #endif
  26         }
  27       ratio = b->r / b->i;
  28       den = b->i * (1 + ratio * ratio);
  29       cr = (a->r * ratio + a->i) / den;
  30       c->i = (a->i * ratio - a->r) / den;
  31     }
  32
  33   else
  34     {
  35       ratio = b->i / b->r;
  36       den = b->r * (1 + ratio * ratio);
  37       cr = (a->r + a->i * ratio) / den;
  38       c->i = (a->i - a->r * ratio) / den;
  39     }
  40   c->r = cr;
  41 }