libf2c/libF77/pow_zz.c

   1 #include "f2c.h"
   2
   3 #undef abs
   4 #include <math.h>
   5 extern double f__cabs (double, double);
   6 void
   7 pow_zz (doublecomplex * r, doublecomplex * a, doublecomplex * b)
   8 {
   9   double logr, logi, x, y;
  10
  11   if (a->r == 0.0 && a->i == 0.0)
  12     {
  13         /* Algorithm below doesn't cope.  */
  14         r->r = r->i = 0.0;
  15         return;
  16     }
  17   logr = log (f__cabs (a->r, a->i));
  18   logi = atan2 (a->i, a->r);
  19
  20   x = exp (logr * b->r - logi * b->i);
  21   y = logr * b->i + logi * b->r;
  22
  23   r->r = x * cos (y);
  24   r->i = x * sin (y);
  25 }