GRASS GIS 8 Programmer's Manual  8.4.0dev(2024)-f4d8c62acd
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 
12 void 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 }
double b
Definition: r_raster.c:39
double t
Definition: r_raster.c:39
void free(void *)
Definition: la.h:54
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