1 /* $Id: c_div.c,v 1.3 2008/02/28 16:48:50 ragge Exp $ */
2 /*
3 * Copyright(C) Caldera International Inc. 2001-2002. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * Redistributions of source code and documentation must retain the above
10 * copyright notice, this list of conditions and the following disclaimer.
11 * Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditionsand the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed or owned by Caldera
17 * International, Inc.
18 * Neither the name of Caldera International, Inc. nor the names of other
19 * contributors may be used to endorse or promote products derived from
20 * this software without specific prior written permission.
21 *
22 * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
23 * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
25 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26 * DISCLAIMED. IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE
27 * FOR ANY DIRECT, INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OFLIABILITY, WHETHER IN CONTRACT,
31 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
34 */
35 #include <stdlib.h>
36
37 #include "f77lib.h"
38
39 void
c_div(complex * c,complex * a,complex * b)40 c_div(complex *c, complex *a, complex *b)
41 {
42 double ratio, den;
43 double abr, abi;
44
45 if( (abr = b->real) < 0.)
46 abr = - abr;
47 if( (abi = b->imag) < 0.)
48 abi = - abi;
49 if( abr <= abi ) {
50 if(abi == 0)
51 abort(); /* fatal("complex division by zero"); */
52 ratio = b->real / b->imag ;
53 den = b->imag * (1 + ratio*ratio);
54 c->real = (a->real*ratio + a->imag) / den;
55 c->imag = (a->imag*ratio - a->real) / den;
56 } else {
57 ratio = b->imag / b->real ;
58 den = b->real * (1 + ratio*ratio);
59 c->real = (a->real + a->imag*ratio) / den;
60 c->imag = (a->imag - a->real*ratio) / den;
61 }
62
63 }
64