UNIX 7th Ed. - /usr/src/libF77/pow_zi.c

   1: #include "complex"
   2: 
   3: pow_zi(p, a, b)     /* p = a**b  */
   4: dcomplex *p, *a;
   5: long int *b;
   6: {
   7: long int n;
   8: double t;
   9: dcomplex x;
  10: 
  11: n = *b;
  12: p->dreal = 1;
  13: p->dimag = 0;
  14: 
  15: if(n == 0)
  16:     return;
  17: if(n < 0)
  18:     {
  19:     n = -n;
  20:     z_div(&x, a);
  21:     }
  22: else
  23:     {
  24:     x.dreal = a->dreal;
  25:     x.dimag = a->dimag;
  26:     }
  27: 
  28: for( ; ; )
  29:     {
  30:     if(n & 01)
  31:         {
  32:         t = p->dreal * x.dreal - p->dimag * x.dimag;
  33:         p->dimag = p->dreal * x.dimag + p->dimag * x.dreal;
  34:         p->dreal = t;
  35:         }
  36:     if(n >>= 1)
  37:         {
  38:         t = x.dreal * x.dreal - x.dimag * x.dimag;
  39:         x.dimag = 2 * x.dreal * x.dimag;
  40:         x.dreal = t;
  41:         }
  42:     else
  43:         break;
  44:     }
  45: }

Defined functions