Used macro instead of function to get the array index

utils/utils.c

@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include "../utils/utils.h"
 
 double *create_sa_matrix(int rows, int cols) {
   double *x;
@@ -12,16 +13,11 @@ void destroy_sa_matrix(double *x) {
   free(x);
 }
 
-int sa_index(int cols, int r, int c) {
-  return r * cols + c;
-}
-
-
 void print_sa_matrix(double *x, int rows, int cols) {
   int i, j;
   for (i = 0; i < rows; i++) {
     for (j = 0; j < cols; j++) {
-      printf("%f\t", x[sa_index(cols, i, j)]);
+      printf("%f\t", x[IDX(cols, i, j)]);
     }
     printf("\n");
   }

utils/utils.h

@@ -9,6 +9,13 @@
 #  define LOG(x) (void) 0 
 #endif
 
+/*
+ * Macro used with single array matrices to
+ * get the array index given the number of columns,
+ * the row index and the column index.
+ */
+#define IDX(cols, r, c) ((r) * (cols) + (c))
+
 typedef struct borders {
   double north;
   double east;
@@ -27,10 +34,6 @@ double *create_sa_matrix(int rows, int cols);
  */
 void destroy_sa_matrix(double *x);
 
-/*
- * Get the index for the single array matrix
- * that correspond to the given row and column.
- */
 int sa_index(int cols, int r, int c);
 
 /*