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cminv.c
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/* cminv.c CCMATH mathematics library source code.
*
* Copyright (C) 2000 Daniel A. Atkinson All rights reserved.
* This code may be redistributed under the terms of the GNU library
* public license (LGPL). ( See the lgpl.license file for details.)
* ------------------------------------------------------------------------
*/
#include <stdlib.h>
#include "ccmath.h"
int cminv(Cpx *a, int n)
{
int i, j, k, m, lc, *le;
Cpx *ps, *p, *q, *pa, *pd;
Cpx z, h, *q0;
double s, t, tq = 0., zr = 1.e-15;
le = (int *)calloc(n, sizeof(int));
q0 = (Cpx *)calloc(n, sizeof(Cpx));
pa = pd = a;
for (j = 0; j < n; ++j, ++pa, pd += n + 1) {
if (j > 0) {
for (i = 0, p = pa, q = q0; i < n; ++i, p += n)
*q++ = *p;
for (i = 1; i < n; ++i) {
lc = i < j ? i : j;
z.re = z.im = 0.;
for (k = 0, p = pa + i * n - j, q = q0; k < lc; ++k, ++q, ++p) {
z.re += p->re * q->re - p->im * q->im;
z.im += p->im * q->re + p->re * q->im;
}
q0[i].re -= z.re;
q0[i].im -= z.im;
}
for (i = 0, p = pa, q = q0; i < n; ++i, p += n)
*p = *q++;
}
s = fabs(pd->re) + fabs(pd->im);
lc = j;
for (k = j + 1, ps = pd; k < n; ++k) {
ps += n;
if ((t = fabs(ps->re) + fabs(ps->im)) > s) {
s = t;
lc = k;
}
}
tq = tq > s ? tq : s;
if (s < zr * tq) {
free(le - j);
free(q0);
return -1;
}
*le++ = lc;
if (lc != j) {
p = a + n * j;
q = a + n * lc;
for (k = 0; k < n; ++k, ++p, ++q) {
h = *p;
*p = *q;
*q = h;
}
}
t = pd->re * pd->re + pd->im * pd->im;
h.re = pd->re / t;
h.im = -(pd->im) / t;
for (k = j + 1, ps = pd + n; k < n; ++k, ps += n) {
z.re = ps->re * h.re - ps->im * h.im;
z.im = ps->im * h.re + ps->re * h.im;
*ps = z;
}
*pd = h;
}
for (j = 1, pd = ps = a; j < n; ++j) {
for (k = 0, pd += n + 1, q = ++ps; k < j; ++k, q += n) {
z.re = q->re * pd->re - q->im * pd->im;
z.im = q->im * pd->re + q->re * pd->im;
*q = z;
}
}
for (j = 1, pa = a; j < n; ++j) {
++pa;
for (i = 0, q = q0, p = pa; i < j; ++i, p += n)
*q++ = *p;
for (k = 0; k < j; ++k) {
h.re = h.im = 0.;
for (i = k, p = pa + k * n + k - j, q = q0 + k; i < j; ++i) {
h.re -= p->re * q->re - p->im * q->im;
h.im -= p->im * q->re + p->re * q->im;
++p;
++q;
}
q0[k] = h;
}
for (i = 0, q = q0, p = pa; i < j; ++i, p += n)
*p = *q++;
}
for (j = n - 2, pd = pa = a + n * n - 1; j >= 0; --j) {
--pa;
pd -= n + 1;
for (i = 0, m = n - j - 1, q = q0, p = pd + n; i < m; ++i, p += n)
*q++ = *p;
for (k = n - 1, ps = pa; k > j; --k, ps -= n) {
z.re = -ps->re;
z.im = -ps->im;
for (i = j + 1, p = ps + 1, q = q0; i < k; ++i, ++p, ++q) {
z.re -= p->re * q->re - p->im * q->im;
z.im -= p->im * q->re + p->re * q->im;
}
q0[--m] = z;
}
for (i = 0, m = n - j - 1, q = q0, p = pd + n; i < m; ++i, p += n)
*p = *q++;
}
for (k = 0, pa = a; k < n - 1; ++k, ++pa) {
for (i = 0, q = q0, p = pa; i < n; ++i, p += n)
*q++ = *p;
for (j = 0, ps = a; j < n; ++j, ps += n) {
if (j > k) {
h.re = h.im = 0.;
p = ps + j;
i = j;
}
else {
h = q0[j];
p = ps + k + 1;
i = k + 1;
}
for (; i < n; ++i, ++p) {
h.re += p->re * q0[i].re - p->im * q0[i].im;
h.im += p->im * q0[i].re + p->re * q0[i].im;
}
q0[j] = h;
}
for (i = 0, q = q0, p = pa; i < n; ++i, p += n)
*p = *q++;
}
for (j = n - 2, le--; j >= 0; --j) {
for (k = 0, p = a + j, q = a + *(--le); k < n; ++k, p += n, q += n) {
h = *p;
*p = *q;
*q = h;
}
}
free(le);
free(q0);
return 0;
}
ccmath.h
Cpx
struct complex Cpx
Definition ccmath.h:41
cminv
int cminv(Cpx *a, int n)
Definition cminv.c:12
t
double t
Definition driver/set_window.c:5
ps
struct ps_state ps
Definition psdriver/graph_set.c:26
complex::re
double re
Definition ccmath.h:39
complex::im
double im
Definition ccmath.h:39