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

#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)
		z->dimag = - z->dimag;
	r->dreal = z->dimag / r->dimag / 2;
	}
}
Commit	Line	Data
0c9e74ab TL	1	#include "complex"
	2
	3	z_sqrt(r, z)
	4	dcomplex r, z;
	5	{
	6	double mag, sqrt(), cabs();
	7
	8	if( (mag = cabs(z->dreal, z->dimag)) == 0.)
	9	r->dreal = r->dimag = 0.;
	10	else if(z->dreal > 0)
	11	{
	12	r->dreal = sqrt(0.5 * (mag + z->dreal) );
	13	r->dimag = z->dimag / r->dreal / 2;
	14	}
	15	else
	16	{
	17	r->dimag = sqrt(0.5 * (mag - z->dreal) );
	18	if(z->dimag < 0)
	19	z->dimag = - z->dimag;
	20	r->dreal = z->dimag / r->dimag / 2;
	21	}
	22	}