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Annotation of 42BSD/usr.lib/libF77/z_div.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  *     "@(#)z_div.c    1.1"
                      3:  */
                      4: 
                      5: #include "complex"
                      6: 
                      7: z_div(c, a, b)
                      8: dcomplex *a, *b, *c;
                      9: {
                     10: double ratio, den;
                     11: double abr, abi;
                     12: 
                     13: if( (abr = b->dreal) < 0.)
                     14:        abr = - abr;
                     15: if( (abi = b->dimag) < 0.)
                     16:        abi = - abi;
                     17: if( abr <= abi )
                     18:        {
                     19:        if(abi == 0)
                     20:                abort(); /* fatal("complex division by zero"); */
                     21:        ratio = b->dreal / b->dimag ;
                     22:        den = b->dimag * (1 + ratio*ratio);
                     23:        c->dreal = (a->dreal*ratio + a->dimag) / den;
                     24:        c->dimag = (a->dimag*ratio - a->dreal) / den;
                     25:        }
                     26: 
                     27: else
                     28:        {
                     29:        ratio = b->dimag / b->dreal ;
                     30:        den = b->dreal * (1 + ratio*ratio);
                     31:        c->dreal = (a->dreal + a->dimag*ratio) / den;
                     32:        c->dimag = (a->dimag - a->dreal*ratio) / den;
                     33:        }
                     34: 
                     35: }

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