pow_zz.c   [plain text]

#include "f2c.h"

#undef abs
#include <math.h>
extern double f__cabs (double, double);
void
pow_zz (doublecomplex * r, doublecomplex * a, doublecomplex * b)
{
  double logr, logi, x, y;

  if (a->r == 0.0 && a->i == 0.0)
    {
	/* Algorithm below doesn't cope.  */
        r->r = r->i = 0.0;
        return;
    }
  logr = log (f__cabs (a->r, a->i));
  logi = atan2 (a->i, a->r);

  x = exp (logr * b->r - logi * b->i);
  y = logr * b->i + logi * b->r;

  r->r = x * cos (y);
  r->i = x * sin (y);
}