GRASS GIS 8 Programmer's Manual 8.3.2(2024)-exported
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atovm.c
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1/* atovm.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 */
8void atovm(double *v, int n)
9{
10 double *p0, *q0, *p, *q, *qq;
11
12 double h, s;
13
14 int i, j, k, mm;
15
16 q0 = v + n * n - 1;
17 *q0 = 1.;
18 q0 -= n + 1;
19 p0 = v + n * n - n - n - 1;
20 for (i = n - 2, mm = 1; i >= 0; --i, p0 -= n + 1, q0 -= n + 1, ++mm) {
21 if (i && *(p0 - 1) != 0.) {
22 for (j = 0, p = p0, h = 1.; j < mm; ++j, ++p)
23 h += *p * *p;
24 h = *(p0 - 1);
25 *q0 = 1. - h;
26 for (j = 0, q = q0 + n, p = p0; j < mm; ++j, q += n)
27 *q = -h * *p++;
28 for (k = i + 1, q = q0 + 1; k < n; ++k) {
29 for (j = 0, qq = q + n, p = p0, s = 0.; j < mm; ++j, qq += n)
30 s += *qq * *p++;
31 s *= h;
32 for (j = 0, qq = q + n, p = p0; j < mm; ++j, qq += n)
33 *qq -= s * *p++;
34 *q++ = -s;
35 }
36 }
37 else {
38 *q0 = 1.;
39 for (j = 0, p = q0 + 1, q = q0 + n; j < mm; ++j, q += n)
40 *q = *p++ = 0.;
41 }
42 }
43}
void atovm(double *v, int n)
Definition atovm.c:8