[unix-history] / usr / src / usr.bin / f77 / libF77 / z_sqrt.c

/*
 *	"@(#)z_sqrt.c	1.1"
 */

#include "complex"

z_sqrt(r, z)
dcomplex *r, *z;
{
double mag, sqrt(), cabs();

if( (mag = cabs(z->dreal, z->dimag)) == 0.)
	r->dreal = r->dimag = 0.;
else if(z->dreal > 0)
	{
	r->dreal = sqrt(0.5 * (mag + z->dreal) );
	r->dimag = z->dimag / r->dreal / 2;
	}
else
	{
	r->dimag = sqrt(0.5 * (mag - z->dreal) );
	if(z->dimag < 0)
		r->dimag = - r->dimag;
	r->dreal = z->dimag / r->dimag / 2;
	}
}
Commit	Line	Data
9381a6f3 DW	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	}