The R Project SVN R

#include "f2c.h"

#ifdef KR_headers
extern void sig_die();
VOID z_div(c, a, b) doublecomplex *a, *b, *c;
#else
extern void sig_die(char*, int);
void z_div(doublecomplex *c, doublecomplex *a, doublecomplex *b)
#endif
{
    double ratio, den;
    double abr, abi;
    double ai = a->i, ar = a->r, bi = b->i, br = b->r;

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

    else
        {
        ratio = bi / br ;
        den = br * (1 + ratio*ratio);
        c->r = (ar + ai*ratio) / den;
        c->i = (ai - ar*ratio) / den;
        }
    }