Fixed coordinates size

futhark_mpi/dispatch.c

@@ -53,7 +53,7 @@ struct dispatch_context {
     int my_rank;
     int world_size;
     int my_cart_rank;
-    int coordinates[2];
+    int coordinates[3];
     MPI_Comm communicators[4]; /* cart_comm, row_comm, column_comm, depth_comm */
     int network_dimensions[3];
     int data_dimensions[3];