GRASS GIS 7 Programmer's Manual  7.9.dev(2019)-f6edaaffa
cminv.c
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1 /* cminv.c CCMATH mathematics library source code.
2  *
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"
10 int cminv(Cpx * a, int n)
11 {
12  int i, j, k, m, lc, *le;
13
14  Cpx *ps, *p, *q, *pa, *pd;
15
16  Cpx z, h, *q0;
17
18  double s, t, tq = 0., zr = 1.e-15;
19
20  le = (int *)calloc(n, sizeof(int));
21  q0 = (Cpx *) calloc(n, sizeof(Cpx));
22  pa = pd = a;
23  for (j = 0; j < n; ++j, ++pa, pd += n + 1) {
24  if (j > 0) {
25  for (i = 0, p = pa, q = q0; i < n; ++i, p += n)
26  *q++ = *p;
27  for (i = 1; i < n; ++i) {
28  lc = i < j ? i : j;
29  z.re = z.im = 0.;
30  for (k = 0, p = pa + i * n - j, q = q0; k < lc; ++k, ++q, ++p) {
31  z.re += p->re * q->re - p->im * q->im;
32  z.im += p->im * q->re + p->re * q->im;
33  }
34  q0[i].re -= z.re;
35  q0[i].im -= z.im;
36  }
37  for (i = 0, p = pa, q = q0; i < n; ++i, p += n)
38  *p = *q++;
39  }
40  s = fabs(pd->re) + fabs(pd->im);
41  lc = j;
42  for (k = j + 1, ps = pd; k < n; ++k) {
43  ps += n;
44  if ((t = fabs(ps->re) + fabs(ps->im)) > s) {
45  s = t;
46  lc = k;
47  }
48  }
49  tq = tq > s ? tq : s;
50  if (s < zr * tq) {
51  free(le - j);
52  free(q0);
53  return -1;
54  }
55  *le++ = lc;
56  if (lc != j) {
57  p = a + n * j;
58  q = a + n * lc;
59  for (k = 0; k < n; ++k, ++p, ++q) {
60  h = *p;
61  *p = *q;
62  *q = h;
63  }
64  }
65  t = pd->re * pd->re + pd->im * pd->im;
66  h.re = pd->re / t;
67  h.im = -(pd->im) / t;
68  for (k = j + 1, ps = pd + n; k < n; ++k, ps += n) {
69  z.re = ps->re * h.re - ps->im * h.im;
70  z.im = ps->im * h.re + ps->re * h.im;
71  *ps = z;
72  }
73  *pd = h;
74  }
75  for (j = 1, pd = ps = a; j < n; ++j) {
76  for (k = 0, pd += n + 1, q = ++ps; k < j; ++k, q += n) {
77  z.re = q->re * pd->re - q->im * pd->im;
78  z.im = q->im * pd->re + q->re * pd->im;
79  *q = z;
80  }
81  }
82  for (j = 1, pa = a; j < n; ++j) {
83  ++pa;
84  for (i = 0, q = q0, p = pa; i < j; ++i, p += n)
85  *q++ = *p;
86  for (k = 0; k < j; ++k) {
87  h.re = h.im = 0.;
88  for (i = k, p = pa + k * n + k - j, q = q0 + k; i < j; ++i) {
89  h.re -= p->re * q->re - p->im * q->im;
90  h.im -= p->im * q->re + p->re * q->im;
91  ++p;
92  ++q;
93  }
94  q0[k] = h;
95  }
96  for (i = 0, q = q0, p = pa; i < j; ++i, p += n)
97  *p = *q++;
98  }
99  for (j = n - 2, pd = pa = a + n * n - 1; j >= 0; --j) {
100  --pa;
101  pd -= n + 1;
102  for (i = 0, m = n - j - 1, q = q0, p = pd + n; i < m; ++i, p += n)
103  *q++ = *p;
104  for (k = n - 1, ps = pa; k > j; --k, ps -= n) {
105  z.re = -ps->re;
106  z.im = -ps->im;
107  for (i = j + 1, p = ps + 1, q = q0; i < k; ++i, ++p, ++q) {
108  z.re -= p->re * q->re - p->im * q->im;
109  z.im -= p->im * q->re + p->re * q->im;
110  }
111  q0[--m] = z;
112  }
113  for (i = 0, m = n - j - 1, q = q0, p = pd + n; i < m; ++i, p += n)
114  *p = *q++;
115  }
116  for (k = 0, pa = a; k < n - 1; ++k, ++pa) {
117  for (i = 0, q = q0, p = pa; i < n; ++i, p += n)
118  *q++ = *p;
119  for (j = 0, ps = a; j < n; ++j, ps += n) {
120  if (j > k) {
121  h.re = h.im = 0.;
122  p = ps + j;
123  i = j;
124  }
125  else {
126  h = q0[j];
127  p = ps + k + 1;
128  i = k + 1;
129  }
130  for (; i < n; ++i, ++p) {
131  h.re += p->re * q0[i].re - p->im * q0[i].im;
132  h.im += p->im * q0[i].re + p->re * q0[i].im;
133  }
134  q0[j] = h;
135  }
136  for (i = 0, q = q0, p = pa; i < n; ++i, p += n)
137  *p = *q++;
138  }
139  for (j = n - 2, le--; j >= 0; --j) {
140  for (k = 0, p = a + j, q = a + *(--le); k < n; ++k, p += n, q += n) {
141  h = *p;
142  *p = *q;
143  *q = h;
144  }
145  }
146  free(le);
147  free(q0);
148  return 0;
149 }
struct ps_state ps
void free(void *)
int cminv(Cpx *a, int n)
Definition: cminv.c:10
double t
Definition: r_raster.c:39
double re
Definition: ccmath.h:38
double im
Definition: ccmath.h:38
Definition: la.h:54