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

#include "f2c.h"

#ifdef KR_headers
extern VOID sig_die();
VOID c_div(c, a, b)
complex *a, *b, *c;
#else
extern void sig_die(char*,int);
void c_div(complex *c, complex *a, complex *b)
#endif
{
double ratio, den;
double abr, abi;

if( (abr = b->r) < 0.)
	abr = - abr;
if( (abi = b->i) < 0.)
	abi = - abi;
if( abr <= abi )
	{
	if(abi == 0)
		sig_die("complex division by zero", 1);
	ratio = (double)b->r / b->i ;
	den = b->i * (1 + ratio*ratio);
	c->r = (a->r*ratio + a->i) / den;
	c->i = (a->i*ratio - a->r) / den;
	}

else
	{
	ratio = (double)b->i / b->r ;
	den = b->r * (1 + ratio*ratio);
	c->r = (a->r + a->i*ratio) / den;
	c->i = (a->i - a->r*ratio) / den;
	}
}
Commit	Line	Data
547779a8 WH	1	#include "f2c.h"
	2
	3	#ifdef KR_headers
	4	extern VOID sig_die();
	5	VOID c_div(c, a, b)
	6	complex a, b, *c;
	7	#else
	8	extern void sig_die(char*,int);
	9	void c_div(complex c, complex a, complex *b)
	10	#endif
	11	{
	12	double ratio, den;
	13	double abr, abi;
	14
	15	if( (abr = b->r) < 0.)
	16	abr = - abr;
	17	if( (abi = b->i) < 0.)
	18	abi = - abi;
	19	if( abr <= abi )
	20	{
	21	if(abi == 0)
	22	sig_die("complex division by zero", 1);
	23	ratio = (double)b->r / b->i ;
	24	den = b->i * (1 + ratio*ratio);
	25	c->r = (a->r*ratio + a->i) / den;
	26	c->i = (a->i*ratio - a->r) / den;
	27	}
	28
	29	else
	30	{
	31	ratio = (double)b->i / b->r ;
	32	den = b->r * (1 + ratio*ratio);
	33	c->r = (a->r + a->i*ratio) / den;
	34	c->i = (a->i - a->r*ratio) / den;
	35	}
	36	}