GRASS GIS 8 Programmer's Manual 8.2.0(2022)-exported
cmmult.c
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1/* cmmult.c CCMATH mathematics library source code.
2 *
3 * Copyright (C) 2000 Daniel A. Atkinson All rights reserved.
4 * This code may be redistributed under the terms of the GNU library
5 * public license (LGPL). ( See the lgpl.license file for details.)
6 * ------------------------------------------------------------------------
7 */
8#include <stdlib.h>
9#include "ccmath.h"
10void cmmult(Cpx * cm, Cpx * a, Cpx * b, int n, int m, int l)
11{
12 Cpx z, *q0, *p, *q;
13
14 int i, j, k;
15
16 q0 = (Cpx *) calloc(m, sizeof(Cpx));
17 for (i = 0; i < l; ++i, ++cm) {
18 for (k = 0, p = b + i; k < m; p += l)
19 q0[k++] = *p;
20 for (j = 0, p = a, q = cm; j < n; ++j, q += l) {
21 for (k = 0, z.re = z.im = 0.; k < m; ++k, ++p) {
22 z.re += p->re * q0[k].re - p->im * q0[k].im;
23 z.im += p->im * q0[k].re + p->re * q0[k].im;
24 }
25 *q = z;
26 }
27 }
28 free(q0);
29}
void cmmult(Cpx *cm, Cpx *a, Cpx *b, int n, int m, int l)
Definition: cmmult.c:10
double b
double l
Definition: ccmath.h:38
double re
Definition: ccmath.h:38
double im
Definition: ccmath.h:38