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-rwxr-xr-xsrc/erasure-code/shec/determinant.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/erasure-code/shec/determinant.c b/src/erasure-code/shec/determinant.c
new file mode 100755
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+++ b/src/erasure-code/shec/determinant.c
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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;
+}