diff --git a/mpi_line/jacobi_mpi_line.c b/mpi_line/jacobi_mpi_line.c
index be18fe3..6946f58 100644
--- a/mpi_line/jacobi_mpi_line.c
+++ b/mpi_line/jacobi_mpi_line.c
@@ -84,6 +84,7 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
   double *x;
   double max_diff, global_max_diff, new_x;
   int i, j;
+  int nb = n + 2; // n plus the border
   int rows, rows_to_transmit;
   int receive_pos;
   MPI_Status status;
@@ -96,25 +97,25 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
   LOG(printf("[Process %d/%d] rows: %d\n", rank, numprocs, rows));
   /* LOG(printf("[Process %d/%d] initializing matrix\n", rank, numprocs)); */
   /* Initialize the matrix */
-  x = create_sa_matrix(rows + 2, n + 2);
+  x = create_sa_matrix(rows + 2, nb);
   for (i = 0; i < rows + 2; i++) {
     for (j = 1; j <= n; j++) {
-      x[IDX(n + 2, i, j)] = init_value;
+      x[IDX(nb, i, j)] = init_value;
     }
   }
   /* Initialize boundary regions */
   for (i = 0; i < rows + 2; i++) {
-    x[IDX(n + 2, i, 0)] = b.west;
-    x[IDX(n + 2, i, n + 1)] = b.east;
+    x[IDX(nb, i, 0)] = b.west;
+    x[IDX(nb, i, n + 1)] = b.east;
   }
   if (rank == 0) {
     for (i = 1; i <= n + 1; i++) {
-      x[IDX(n + 2, 0, i)] = b.north;
+      x[IDX(nb, 0, i)] = b.north;
     }
   }
   if (rank == numprocs - 1){
     for (i = 1; i < n + 1; i++) {
-      x[IDX(n + 2, rows + 1, i)] = b.south;
+      x[IDX(nb, rows + 1, i)] = b.south;
     }
   }
   /* LOG(printf("[Process %d/%d] matrix initialized\n", rank, numprocs)); */
@@ -125,30 +126,30 @@ 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[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;
+        new_x = 0.25 * (x[IDX(nb, i - 1, j)] + x[IDX(nb, i, j + 1)] + x[IDX(nb, i + 1, j)] + x[IDX(nb, i, j - 1)]);
+        max_diff = (double) fmax(max_diff, fabs(new_x - x[IDX(nb, i, j)]));
+        x[IDX(nb, i, j)] = new_x;
       }
     }
     if (rank % 2 == 0) {
       if (rank != numprocs - 1) {
         // Send and receive south border
-        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);
+        MPI_Send(&x[IDX(nb, rows, 0)], nb, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Recv(&x[IDX(nb, rows + 1, 0)], nb, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
       }
       if (rank != 0) {
         // Send and receive north border
-        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);
+        MPI_Send(&x[IDX(nb, 1, 0)], nb, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Recv(&x[IDX(nb, 0, 0)], nb, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD, &status);
       }
     } else {
       // Receive and send north border
-      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);
+      MPI_Recv(&x[IDX(nb, 0, 0)], nb, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+      MPI_Send(&x[IDX(nb, 1, 0)], nb, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
       if (rank != numprocs - 1) {
         // Receive and send south border
-        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);
+        MPI_Recv(&x[IDX(nb, rows + 1, 0)], nb, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+        MPI_Send(&x[IDX(nb, rows, 0)], nb, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
       }
     }
     /* LOG(printf("[Process %d/%d] max_diff: %f\n", rank, numprocs, max_diff)); */
@@ -158,15 +159,15 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
   } while (global_max_diff > threshold);
 
   if (rank == 0) {
-    complete_x = create_sa_matrix(n + 2, n + 2);
-    memcpy(complete_x, x, (rows + ((rank == numprocs - 1) ? 2 : 1)) * (n + 2) * sizeof(double));
+    complete_x = create_sa_matrix(nb, nb);
+    memcpy(complete_x, x, (rows + ((rank == numprocs - 1) ? 2 : 1)) * (nb) * sizeof(double));
     rows_to_transmit = n / numprocs;
     receive_pos = rows + 1;
     for (i = 1; i < numprocs; i++) {
       if (i == numprocs - 1) {
         rows_to_transmit++;
       }
-      MPI_Recv(&complete_x[IDX(n + 2, receive_pos, 0)], rows_to_transmit * (n + 2), MPI_DOUBLE, i, TAG_MATRIX, MPI_COMM_WORLD, &status);
+      MPI_Recv(&complete_x[IDX(nb, receive_pos, 0)], rows_to_transmit * (nb), MPI_DOUBLE, i, TAG_MATRIX, MPI_COMM_WORLD, &status);
       receive_pos += n / numprocs;
     }
   } else {
@@ -175,7 +176,7 @@ double *compute_jacobi(int n, double init_value, double threshold, borders b, in
     if (rank == numprocs - 1) {
       rows_to_transmit++;
     }
-    MPI_Send(&x[IDX(n + 2, 1, 0)], rows_to_transmit * (n + 2), MPI_DOUBLE, 0, TAG_MATRIX, MPI_COMM_WORLD);
+    MPI_Send(&x[IDX(nb, 1, 0)], rows_to_transmit * (nb), MPI_DOUBLE, 0, TAG_MATRIX, MPI_COMM_WORLD);
   }
 
   return complete_x;