2.9BSD - /usr/src/lib/libF77/z_sqrt.c

   1: /*
   2:  *	"@(#)z_sqrt.c	1.1"
   3:  */
   4: 
   5: #include "complex"
   6: 
   7: z_sqrt(r, z)
   8: dcomplex *r, *z;
   9: {
  10: double mag, sqrt(), cabs();
  11: 
  12: if( (mag = cabs(z->dreal, z->dimag)) == 0.)
  13:     r->dreal = r->dimag = 0.;
  14: else if(z->dreal > 0)
  15:     {
  16:     r->dreal = sqrt(0.5 * (mag + z->dreal) );
  17:     r->dimag = z->dimag / r->dreal / 2;
  18:     }
  19: else
  20:     {
  21:     r->dimag = sqrt(0.5 * (mag - z->dreal) );
  22:     if(z->dimag < 0)
  23:         r->dimag = - r->dimag;
  24:     r->dreal = z->dimag / r->dimag / 2;
  25:     }
  26: }

Defined functions