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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2014 Fujitsu Laboratories
*
* Author: Takanori Nakao <nakao.takanori@jp.fujitsu.com>
* Author: Takeshi Miyamae <miyamae.takeshi@jp.fujitsu.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "jerasure/include/galois.h"
void print_matrix(int *mat, int dim)
{
int i, j;
for (i=0; i<dim; i++) {
for (j=0; j<dim; j++) {
printf("%d ", mat[i*dim+j]);
}
printf("\n");
}
}
int calc_determinant(int *matrix, int dim)
{
int i, j, k, *mat, det = 1, coeff_1, coeff_2, *row;
// print_matrix(matrix, dim);
mat = (int *)malloc(sizeof(int)*dim*dim);
if (mat == NULL) {
printf("mat malloc err\n");
goto out0;
}
memcpy((int *)mat, (int *)matrix, sizeof(int)*dim*dim);
row = (int *)malloc(sizeof(int)*dim);
if (row == NULL) {
printf("row malloc err\n");
goto out1;
}
for (i=0; i<dim; i++) {
if (mat[i*dim+i] == 0) {
for (k=i+1; k<dim; k++) {
if (mat[k*dim+i] != 0) {
memcpy((int *)row, (int *)&mat[k*dim], sizeof(int)*dim);
memcpy((int *)&mat[k*dim], (int *)&mat[i*dim], sizeof(int)*dim);
memcpy((int *)&mat[i*dim], (int *)row, sizeof(int)*dim);
break;
}
}
if (k == dim) {
det = 0;
goto out2;
}
}
coeff_1 = mat[i*dim+i];
for (j=i; j<dim; j++) {
mat[i*dim+j] = galois_single_divide(mat[i*dim+j], coeff_1, 8);
}
for (k=i+1; k<dim; k++) {
if (mat[k*dim+i] != 0) {
coeff_2 = mat[k*dim+i];
for (j=i; j<dim; j++) {
mat[k*dim+j] = mat[k*dim+j] ^ galois_single_multiply(mat[i*dim+j], coeff_2, 8);
}
}
}
det = galois_single_multiply(det, coeff_1, 8);
}
// print_matrix(mat, dim);
out2:
free(row);
out1:
free(mat);
out0:
return det;
}
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