Merge pull request #648 from streeve/fixup_ex_comm_rank

Use Cajita comm rank in examples

example/cajita_tutorial/04_global_grid/global_grid_example.cpp

@@ -23,14 +23,6 @@ void globalGridExample()
       physical size and characteristics of the mesh. The global grid accordingly
       defines indexing throughout the entire mesh domain.
     */
-    int comm_rank = -1;
-    MPI_Comm_rank( MPI_COMM_WORLD, &comm_rank );
-
-    if ( comm_rank == 0 )
-    {
-        std::cout << "Cajita Global Grid Example" << std::endl;
-        std::cout << "    (intended to be run with MPI)\n" << std::endl;
-    }
 
     /*
       Both the global mesh and partitioning information are necessary to create
@@ -62,6 +54,14 @@ void globalGridExample()
     auto global_grid = Cajita::createGlobalGrid( MPI_COMM_WORLD, global_mesh,
                                                  is_dim_periodic, partitioner );
 
+    // Get the current rank for printing output.
+    int comm_rank = global_grid->blockId();
+    if ( comm_rank == 0 )
+    {
+        std::cout << "Cajita Global Grid Example" << std::endl;
+        std::cout << "    (intended to be run with MPI)\n" << std::endl;
+    }
+
     /*
       Now extract grid details that are the same globally (on each MPI rank):
       periodicity, number of blocks (MPI decomposition) in total and per

example/cajita_tutorial/06_local_grid/local_grid_example.cpp

@@ -31,14 +31,6 @@ void localGridExample()
       Cajita subpackage as application users will likely interact with it the
       most and it includes interfaces to all other grid/mesh classes.
     */
-    int comm_rank = -1;
-    MPI_Comm_rank( MPI_COMM_WORLD, &comm_rank );
-
-    if ( comm_rank == 0 )
-    {
-        std::cout << "Cajita Local Grid Example" << std::endl;
-        std::cout << "    (intended to be run with MPI)\n" << std::endl;
-    }
 
     // Here we partition only in x to simplify the example below.
     int comm_size;
@@ -58,6 +50,14 @@ void localGridExample()
     auto global_grid = Cajita::createGlobalGrid( MPI_COMM_WORLD, global_mesh,
                                                  is_dim_periodic, partitioner );
 
+    // Get the current rank for printing output.
+    int comm_rank = global_grid->blockId();
+    if ( comm_rank == 0 )
+    {
+        std::cout << "Cajita Local Grid Example" << std::endl;
+        std::cout << "    (intended to be run with MPI)\n" << std::endl;
+    }
+
     /*
       We create the local grid from the global grid and a halo width -
       the number of cells communicated with MPI neighbor ranks. The halo width

example/cajita_tutorial/07_local_mesh/local_mesh_example.cpp

@@ -32,15 +32,6 @@ void localMeshExample()
       local mesh, including ghost information.
     */
 
-    int comm_rank = -1;
-    MPI_Comm_rank( MPI_COMM_WORLD, &comm_rank );
-
-    if ( comm_rank == 0 )
-    {
-        std::cout << "Cajita Local Mesh Example" << std::endl;
-        std::cout << "    (intended to be run with MPI)\n" << std::endl;
-    }
-
     using exec_space = Kokkos::DefaultHostExecutionSpace;
     using device_type = exec_space::device_type;
 
@@ -65,6 +56,14 @@ void localMeshExample()
     auto global_grid = Cajita::createGlobalGrid( MPI_COMM_WORLD, global_mesh,
                                                  is_dim_periodic, partitioner );
 
+    // Get the current rank for printing output.
+    int comm_rank = global_grid->blockId();
+    if ( comm_rank == 0 )
+    {
+        std::cout << "Cajita Local Mesh Example" << std::endl;
+        std::cout << "    (intended to be run with MPI)\n" << std::endl;
+    }
+
     // Create a local grid
     int halo_width = 1;
     auto local_grid = Cajita::createLocalGrid( global_grid, halo_width );

example/cajita_tutorial/08_array/array_example.cpp

@@ -29,15 +29,6 @@ void arrayExample()
       data itself and may only be defined on a single entity type.
     */
 
-    int comm_rank = -1;
-    MPI_Comm_rank( MPI_COMM_WORLD, &comm_rank );
-
-    if ( comm_rank == 0 )
-    {
-        std::cout << "Cajita Array Example" << std::endl;
-        std::cout << "    (intended to be run with MPI)\n" << std::endl;
-    }
-
     using exec_space = Kokkos::DefaultHostExecutionSpace;
     using device_type = exec_space::device_type;
 
@@ -69,6 +60,14 @@ void arrayExample()
     auto global_grid = Cajita::createGlobalGrid( MPI_COMM_WORLD, global_mesh,
                                                  is_dim_periodic, partitioner );
 
+    // Get the current rank for printing output.
+    int comm_rank = global_grid->blockId();
+    if ( comm_rank == 0 )
+    {
+        std::cout << "Cajita Array Example" << std::endl;
+        std::cout << "    (intended to be run with MPI)\n" << std::endl;
+    }
+
     /*
       An array layout includes the local grid size information together with the
       dimensionality of the field data, the degrees of freedom on the mesh.

example/cajita_tutorial/12_halo/halo_example.cpp

@@ -37,15 +37,6 @@ void gridHaloExample()
       plan and performing both scatter and gather operations.
     */
 
-    int comm_rank = -1;
-    MPI_Comm_rank( MPI_COMM_WORLD, &comm_rank );
-
-    if ( comm_rank == 0 )
-    {
-        std::cout << "Cajita Grid Halo Example" << std::endl;
-        std::cout << "    (intended to be run with MPI)\n" << std::endl;
-    }
-
     using exec_space = Kokkos::DefaultHostExecutionSpace;
     using device_type = exec_space::device_type;
 
@@ -81,6 +72,14 @@ void gridHaloExample()
     auto global_grid = createGlobalGrid( MPI_COMM_WORLD, global_mesh,
                                          is_dim_periodic, partitioner );
 
+    // Get the current rank for printing output.
+    int comm_rank = global_grid->blockId();
+    if ( comm_rank == 0 )
+    {
+        std::cout << "Cajita Grid Halo Example" << std::endl;
+        std::cout << "    (intended to be run with MPI)\n" << std::endl;
+    }
+
     /*
       Here the halo width allocated for the system is not necessarily always
       fully communicated - we can use any integer value from zero to the value

example/cajita_tutorial/13_all_loadbalancer/loadbalancer_example.cpp

@@ -61,14 +61,6 @@ void loadBalancerExample()
      * application using Cajita without load balancing; the comments will be
      * focused on the additions/changes due to including the load balancer.
      */
-    int comm_rank = -1;
-    MPI_Comm_rank( MPI_COMM_WORLD, &comm_rank );
-
-    if ( comm_rank == 0 )
-    {
-        std::cout << "Cajita Load Balancer Example" << std::endl;
-        std::cout << "    (intended to be run with MPI)\n" << std::endl;
-    }
 
     /*
      * The example system is 2D and its size based on the number of ranks. Every
@@ -99,6 +91,14 @@ void loadBalancerExample()
     auto global_grid = Cajita::createGlobalGrid( MPI_COMM_WORLD, global_mesh,
                                                  is_dim_periodic, partitioner );
 
+    // Get the current rank for printing output.
+    int comm_rank = global_grid->blockId();
+    if ( comm_rank == 0 )
+    {
+        std::cout << "Cajita Load Balancer Example" << std::endl;
+        std::cout << "    (intended to be run with MPI)\n" << std::endl;
+    }
+
     /*
      * The load balancer is initialized using the global grid and MPI
      * communicator. The additional minimum domain size is optional and, if