[unix-history] / lib / libF77 / z_sqrt.c

#include "f2c.h"

#ifdef KR_headers
double sqrt(), f__cabs();
VOID z_sqrt(r, z) doublecomplex *r, *z;
#else
#undef abs
#include "math.h"
extern double f__cabs(double, double);
void z_sqrt(doublecomplex *r, doublecomplex *z)
#endif
{
double mag;

if( (mag = f__cabs(z->r, z->i)) == 0.)
	r->r = r->i = 0.;
else if(z->r > 0)
	{
	r->r = sqrt(0.5 * (mag + z->r) );
	r->i = z->i / r->r / 2;
	}
else
	{
	r->i = sqrt(0.5 * (mag - z->r) );
	if(z->i < 0)
		r->i = - r->i;
	r->r = z->i / r->i / 2;
	}
}
Commit	Line	Data
547779a8 WH	1	#include "f2c.h"
	2
	3	#ifdef KR_headers
	4	double sqrt(), f__cabs();
	5	VOID z_sqrt(r, z) doublecomplex r, z;
	6	#else
	7	#undef abs
	8	#include "math.h"
	9	extern double f__cabs(double, double);
	10	void z_sqrt(doublecomplex r, doublecomplex z)
	11	#endif
	12	{
	13	double mag;
	14
	15	if( (mag = f__cabs(z->r, z->i)) == 0.)
	16	r->r = r->i = 0.;
	17	else if(z->r > 0)
	18	{
	19	r->r = sqrt(0.5 * (mag + z->r) );
	20	r->i = z->i / r->r / 2;
	21	}
	22	else
	23	{
	24	r->i = sqrt(0.5 * (mag - z->r) );
	25	if(z->i < 0)
	26	r->i = - r->i;
	27	r->r = z->i / r->i / 2;
	28	}
	29	}