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Annotation of 43BSDTahoe/usr.lib/libF77/c_div.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1980 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  *
                      6:  *     @(#)c_div.c     5.1     6/7/85
                      7:  */
                      8: 
                      9: #include "complex"
                     10: #include <stdio.h>
                     11: #include <errno.h>
                     12: 
                     13: c_div(c, a, b)
                     14: complex *a, *b, *c;
                     15: {
                     16: double ratio, den;
                     17: double abr, abi;
                     18: 
                     19: if( (abr = b->real) < 0.)
                     20:        abr = - abr;
                     21: if( (abi = b->imag) < 0.)
                     22:        abi = - abi;
                     23: if( abr <= abi )
                     24:        {
                     25:        if(abi == 0) {
                     26:                fprintf(stderr,"complex division by zero\n");
                     27:                f77_abort(EDOM);
                     28:        }
                     29:        ratio = b->real / b->imag ;
                     30:        den = b->imag * (1 + ratio*ratio);
                     31:        c->real = (a->real*ratio + a->imag) / den;
                     32:        c->imag = (a->imag*ratio - a->real) / den;
                     33:        }
                     34: 
                     35: else
                     36:        {
                     37:        ratio = b->imag / b->real ;
                     38:        den = b->real * (1 + ratio*ratio);
                     39:        c->real = (a->real + a->imag*ratio) / den;
                     40:        c->imag = (a->imag - a->real*ratio) / den;
                     41:        }
                     42: 
                     43: }

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