File:  [Research Unix] / researchv8dc / libF77 / z_sqrt.c
Revision 1.1.1.1 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 17:21:59 2018 UTC (2 years, 2 months ago) by root
Branches: belllabs, MAIN
CVS tags: researchv8, HEAD
researchv8 Dan Cross

#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;
	}
}

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