Geografic-Information-System/lib/external/ccmath/rmmult.c

/*  rmmult.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>
void rmmult(double *rm, double *a, double *b, int n, int m, int l)
{
    double z, *q0, *p, *q;

    int i, j, k;

    q0 = (double *)calloc(m, sizeof(double));
    for (i = 0; i < l; ++i, ++rm) {
	for (k = 0, p = b + i; k < m; p += l)
	    q0[k++] = *p;
	for (j = 0, p = a, q = rm; j < n; ++j, q += l) {
	    for (k = 0, z = 0.; k < m;)
		z += *p++ * q0[k++];
	    *q = z;
	}
    }
    free(q0);
}