3 * $Id: matrix.c,v 1.3 2000/08/05 11:27:56 mdw Exp $
5 * Matrix arithmetic mod %$2^{24}$%
7 * (c) 2000 Mark Wooding
10 /*----- Licensing notice --------------------------------------------------*
12 * Copyright (c) 2000 Mark Wooding
13 * All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions are
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
22 * 2, Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
26 * 3. The name of the authors may not be used to endorse or promote
27 * products derived from this software without specific prior written
30 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
31 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
32 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
33 * NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
34 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
35 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
36 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
38 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
39 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
40 * POSSIBILITY OF SUCH DAMAGE.
42 * Instead of accepting the above terms, you may redistribute and/or modify
43 * this software under the terms of either the GNU General Public License,
44 * or the GNU Library General Public License, published by the Free
45 * Software Foundation; either version 2 of the License, or (at your
46 * option) any later version.
49 /*----- Revision history --------------------------------------------------*
52 * Revision 1.3 2000/08/05 11:27:56 mdw
53 * (matinv): Fix type error.
55 * Revision 1.2 2000/07/02 15:22:07 mdw
56 * Fix licence text. Change to matinv to mark inputs as constants.
58 * Revision 1.1 2000/05/21 11:28:30 mdw
63 /*----- Header files ------------------------------------------------------*/
73 /*----- Main code ---------------------------------------------------------*/
77 * Arguments: @uint24 *d@ = pointer to destination matrix
78 * @uint24 *a, *b@ = pointer to operand matrices
79 * @unsigned x, y, z@ = dimensions of the operand matrices
83 * Use: Performs matrix multiplication mod %$2^{24}$%. The matrix
84 * @d@ may not overlap either operand matrix.
87 void matmul(uint24 *d, const uint24 *a, const uint24 *b,
88 unsigned x, unsigned y, unsigned z)
92 for (i = 0; i < x; i++) {
94 for (j = 0; j < z; j++) {
96 for (k = 0; k < y; k++)
97 n += a[k] * bb[k * z];
105 /* --- @matinv@ --- *
107 * Arguments: @uint24 *d@ = pointer to destination matrix
108 * @const uint24 *a@ = pointer to operand matrix
109 * @unsigned x, y@ = dimensions of operand matrix
111 * Returns: Zero if the matrix was successfully inverted, %$-1$% if the
112 * matrix is singular.
114 * Use: Computes the mod %$2^{24}$% inverse of a square matrix.
117 int matinv(uint24 *d, const uint24 *a, unsigned x, unsigned y)
121 uint24 *p, *q, *r, *s;
125 aa = malloc(sizeof(uint24) * x * y);
127 fprintf(stderr, "unable to allocate memory\n");
130 memcpy(aa, a, sizeof(uint24) * x * y);
133 for (i = 0; i < x; i++) {
134 for (j = 0; j < y; j++)
138 for (i = 0; i < x; i++) {
139 uint24 c = inv24(aa[(x + 1) * i]);
144 for (j = 0; j < y; j++) {
145 r[j] = U24(r[j] * c);
146 s[j] = U24(s[j] * c);
148 for (j = 0; j < x; j++) {
154 for (k = 0; k < y; k++) {
155 p[k] = U24(p[k] - c * r[k]);
156 q[k] = U24(q[k] - c * s[k]);
169 /*----- That's all, folks -------------------------------------------------*/