GRASS GIS 8 Programmer's Manual 8.4.1(2025)-45ca3179ab
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utrnhm.c
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1/* utrnhm.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
9#include <stdlib.h>
10#include "ccmath.h"
11
12void utrnhm(Cpx *hm, Cpx *a, Cpx *b, int n)
13{
14 Cpx z, *q0, *p, *s, *t;
15
16 int i, j, k;
17
18 q0 = (Cpx *)calloc(n, sizeof(Cpx));
19 for (i = 0; i < n; ++i) {
20 for (j = 0, t = b; j < n; ++j) {
21 z.re = z.im = 0.;
22 for (k = 0, s = a + i * n; k < n; ++k, ++s, ++t) {
23 z.re += t->re * s->re + t->im * s->im;
24 z.im += t->im * s->re - t->re * s->im;
25 }
26 q0[j] = z;
27 }
28 for (j = 0, p = hm + i, t = a; j <= i; ++j, p += n) {
29 z.re = z.im = 0.;
30 for (k = 0, s = q0; k < n; ++k, ++t, ++s) {
31 z.re += t->re * s->re - t->im * s->im;
32 z.im += t->im * s->re + t->re * s->im;
33 }
34 *p = z;
35 if (j < i) {
36 z.im = -z.im;
37 hm[i * n + j] = z;
38 }
39 }
40 }
41 free(q0);
42}
struct complex Cpx
Definition ccmath.h:41
double b
double t
double re
Definition ccmath.h:39
double im
Definition ccmath.h:39
void utrnhm(Cpx *hm, Cpx *a, Cpx *b, int n)
Definition utrnhm.c:12