107 lines
4.0 KiB
C
107 lines
4.0 KiB
C
/* *
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* Copyright (c) 2013, James S. Plank and Kevin Greenan
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* All rights reserved.
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*
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* Jerasure - A C/C++ Library for a Variety of Reed-Solomon and RAID-6 Erasure
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* Coding Techniques
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*
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* Revision 2.0: Galois Field backend now links to GF-Complete
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* - Neither the name of the University of Tennessee nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
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* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "jerasure.h"
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#define talloc(type, num) (type *) malloc(sizeof(type)*(num))
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usage(char *s)
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{
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fprintf(stderr, "usage: jerasure_03 k w - Creates a kxk Cauchy matrix in GF(2^w). \n\n");
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fprintf(stderr, " k must be < 2^w. Element i,j is 1/(i+(2^w-j-1)). (If that is\n");
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fprintf(stderr, " 1/0, then it sets it to zero). \n");
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fprintf(stderr, " It then tests whether that matrix is invertible.\n");
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fprintf(stderr, " If it is invertible, then it prints out the inverse.\n");
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fprintf(stderr, " Finally, it prints the product of the matrix and its inverse.\n");
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fprintf(stderr, " \n");
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fprintf(stderr, "This demonstrates: jerasure_print_matrix()\n");
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fprintf(stderr, " jerasure_invertible_matrix()\n");
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fprintf(stderr, " jerasure_invert_matrix()\n");
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fprintf(stderr, " jerasure_matrix_multiply().\n");
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if (s != NULL) fprintf(stderr, "%s\n", s);
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exit(1);
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}
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int main(int argc, char **argv)
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{
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unsigned int k, w, i, j, n;
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int *matrix;
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int *matrix_copy;
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int *inverse;
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int *identity;
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if (argc != 3) usage(NULL);
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if (sscanf(argv[1], "%d", &k) == 0 || k <= 0) usage("Bad k");
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if (sscanf(argv[2], "%d", &w) == 0 || w <= 0 || w > 31) usage("Bad w");
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if (k >= (1 << w)) usage("K too big");
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matrix = talloc(int, k*k);
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matrix_copy = talloc(int, k*k);
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inverse = talloc(int, k*k);
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for (i = 0; i < k; i++) {
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for (j = 0; j < k; j++) {
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n = i ^ ((1 << w)-1-j);
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matrix[i*k+j] = (n == 0) ? 0 : galois_single_divide(1, n, w);
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}
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}
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printf("The Cauchy Matrix:\n");
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jerasure_print_matrix(matrix, k, k, w);
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memcpy(matrix_copy, matrix, sizeof(int)*k*k);
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i = jerasure_invertible_matrix(matrix_copy, k, w);
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printf("\nInvertible: %s\n", (i == 1) ? "Yes" : "No");
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if (i == 1) {
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printf("\nInverse:\n");
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memcpy(matrix_copy, matrix, sizeof(int)*k*k);
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i = jerasure_invert_matrix(matrix_copy, inverse, k, w);
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jerasure_print_matrix(inverse, k, k, w);
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identity = jerasure_matrix_multiply(inverse, matrix, k, k, k, k, w);
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printf("\nInverse times matrix (should be identity):\n");
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jerasure_print_matrix(identity, k, k, w);
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}
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return 0;
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}
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