diff --git a/mpi_line/jacobi.conf b/mpi_line/jacobi.conf
index f1121d4..3e7fd02 100644
--- a/mpi_line/jacobi.conf
+++ b/mpi_line/jacobi.conf
@@ -1,7 +1,7 @@
 # Configuration file for the Jacobi project.
 
 # The size of the matrix (borders excluded).
-N 5000
+N 5
 
 # The value at each border.
 NORTH 0.0
diff --git a/mpi_line/jacobi_mpi_line.c b/mpi_line/jacobi_mpi_line.c
index 6ca8f5f..be18fe3 100644
--- a/mpi_line/jacobi_mpi_line.c
+++ b/mpi_line/jacobi_mpi_line.c
@@ -69,7 +69,7 @@ int main(int argc, char* argv[]) {
     endwtime = MPI_Wtime();
     printf("Wall clock time: %fs\n", endwtime - startwtime);
     printf("Iterations: %d\n", iterations);
-    /* print_sa_matrix(x, n + 2, n + 2); */
+    print_sa_matrix(x, n + 2, n + 2);
   }
 
   destroy_sa_matrix(x);
@@ -99,22 +99,22 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
   x = create_sa_matrix(rows + 2, n + 2);
   for (i = 0; i < rows + 2; i++) {
     for (j = 1; j <= n; j++) {
-      x[sa_index(n + 2, i, j)] = init_value;
+      x[IDX(n + 2, i, j)] = init_value;
     }
   }
   /* Initialize boundary regions */
   for (i = 0; i < rows + 2; i++) {
-    x[sa_index(n + 2, i, 0)] = b.west;
-    x[sa_index(n + 2, i, n + 1)] = b.east;
+    x[IDX(n + 2, i, 0)] = b.west;
+    x[IDX(n + 2, i, n + 1)] = b.east;
   }
   if (rank == 0) {
     for (i = 1; i <= n + 1; i++) {
-      x[sa_index(n + 2, 0, i)] = b.north;
+      x[IDX(n + 2, 0, i)] = b.north;
     }
   }
   if (rank == numprocs - 1){
     for (i = 1; i < n + 1; i++) {
-      x[sa_index(n + 2, rows + 1, i)] = b.south;
+      x[IDX(n + 2, rows + 1, i)] = b.south;
     }
   }
   /* LOG(printf("[Process %d/%d] matrix initialized\n", rank, numprocs)); */
@@ -125,30 +125,30 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
     global_max_diff = 0;
     for (i = 1; i <= rows; i++) {
       for (j = 1; j <= n; j++) {
-        new_x = 0.25 * (x[sa_index(n + 2, i - 1, j)] + x[sa_index(n + 2, i, j + 1)] + x[sa_index(n + 2, i + 1, j)] + x[sa_index(n + 2, i, j - 1)]);
-        max_diff = (double) fmax(max_diff, fabs(new_x - x[sa_index(n + 2, i, j)]));
-        x[sa_index(n + 2, i, j)] = new_x;
+        new_x = 0.25 * (x[IDX(n + 2, i - 1, j)] + x[IDX(n + 2, i, j + 1)] + x[IDX(n + 2, i + 1, j)] + x[IDX(n + 2, i, j - 1)]);
+        max_diff = (double) fmax(max_diff, fabs(new_x - x[IDX(n + 2, i, j)]));
+        x[IDX(n + 2, i, j)] = new_x;
       }
     }
     if (rank % 2 == 0) {
       if (rank != numprocs - 1) {
         // Send and receive south border
-        MPI_Send(&x[sa_index(n + 2, rows, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
-        MPI_Recv(&x[sa_index(n + 2, rows + 1, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+        MPI_Send(&x[IDX(n + 2, rows, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Recv(&x[IDX(n + 2, rows + 1, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
       }
       if (rank != 0) {
         // Send and receive north border
-        MPI_Send(&x[sa_index(n + 2, 1, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
-        MPI_Recv(&x[sa_index(n + 2, 0, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+        MPI_Send(&x[IDX(n + 2, 1, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Recv(&x[IDX(n + 2, 0, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD, &status);
       }
     } else {
       // Receive and send north border
-      MPI_Recv(&x[sa_index(n + 2, 0, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD, &status);
-      MPI_Send(&x[sa_index(n + 2, 1, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
+      MPI_Recv(&x[IDX(n + 2, 0, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+      MPI_Send(&x[IDX(n + 2, 1, 0)], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
       if (rank != numprocs - 1) {
         // Receive and send south border
-        MPI_Recv(&x[sa_index(n + 2, rows + 1, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
-        MPI_Send(&x[sa_index(n + 2, rows, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Recv(&x[IDX(n + 2, rows + 1, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+        MPI_Send(&x[IDX(n + 2, rows, 0)], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
       }
     }
     /* LOG(printf("[Process %d/%d] max_diff: %f\n", rank, numprocs, max_diff)); */
@@ -166,7 +166,7 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
       if (i == numprocs - 1) {
         rows_to_transmit++;
       }
-      MPI_Recv(&complete_x[sa_index(n + 2, receive_pos, 0)], rows_to_transmit * (n + 2), MPI_DOUBLE, i, TAG_MATRIX, MPI_COMM_WORLD, &status);
+      MPI_Recv(&complete_x[IDX(n + 2, receive_pos, 0)], rows_to_transmit * (n + 2), MPI_DOUBLE, i, TAG_MATRIX, MPI_COMM_WORLD, &status);
       receive_pos += n / numprocs;
     }
   } else {
@@ -175,7 +175,7 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
     if (rank == numprocs - 1) {
       rows_to_transmit++;
     }
-    MPI_Send(&x[sa_index(n + 2, 1, 0)], rows_to_transmit * (n + 2), MPI_DOUBLE, 0, TAG_MATRIX, MPI_COMM_WORLD);
+    MPI_Send(&x[IDX(n + 2, 1, 0)], rows_to_transmit * (n + 2), MPI_DOUBLE, 0, TAG_MATRIX, MPI_COMM_WORLD);
   }
 
   return complete_x;
diff --git a/utils/utils.c b/utils/utils.c
index bf533c0..30fda51 100644
--- a/utils/utils.c
+++ b/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");
   }
diff --git a/utils/utils.h b/utils/utils.h
index 29c343f..eb0b37c 100644
--- a/utils/utils.h
+++ b/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);
 
 /*