text: #include "f2c.h"
  
  #ifdef KR_headers
  double sqrt(), f__cabs();
  VOID z_sqrt(r, z) doublecomplex *r, *z;
  #else
  #undef abs
  #include "math.h"
  #ifdef __cplusplus
  extern "C" {
  #endif
  extern double f__cabs(double, double);
  void z_sqrt(doublecomplex *r, doublecomplex *z)
  #endif
  {
  	double mag, zi = z->i, zr = z->r;
  
  	if( (mag = f__cabs(zr, zi)) == 0.)
  		r->r = r->i = 0.;
  	else if(zr > 0)
  		{
  		r->r = sqrt(0.5 * (mag + zr) );
  		r->i = zi / r->r / 2;
  		}
  	else
  		{
  		r->i = sqrt(0.5 * (mag - zr) );
  		if(zi < 0)
  			r->i = - r->i;
  		r->r = zi / r->i / 2;
  		}
  	}
  #ifdef __cplusplus
  }
  #endif
  