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 100644
index 000000000..15b62c9ef
--- /dev/null
+++ b/src/erasure-code/shec/determinant.c
@@ -0,0 +1,94 @@
+// -*- 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;
+}