Update examples to build with latest changes to cugraph (#4632)

We don't build the examples as part of CI.  Some changes were made to the cugraph functions that cause the examples to be out of date.

Also, we should release the RAFT handle before calling MPI_Finalize.

Authors:
  - Chuck Hastings (https://github.com/ChuckHastings)

Approvers:
  - Seunghwa Kang (https://github.com/seunghwak)

URL: #4632

cpp/examples/developers/graph_operations/graph_operations.cu

@@ -131,7 +131,7 @@ create_graph(raft::handle_t const& handle,
   //
 
   if (multi_gpu) {
-    std::tie(d_edge_srcs, d_edge_dsts, d_edge_wgts, std::ignore, std::ignore) =
+    std::tie(d_edge_srcs, d_edge_dsts, d_edge_wgts, std::ignore, std::ignore, std::ignore) =
       cugraph::shuffle_external_edges<vertex_t, vertex_t, weight_t, int32_t>(handle,
                                                                              std::move(d_edge_srcs),
                                                                              std::move(d_edge_dsts),
@@ -215,10 +215,10 @@ void perform_example_graph_operations(
                                                                                   graph_view);
 
     cugraph::update_edge_src_property(
-      handle, graph_view, vertex_weights.begin(), src_vertex_weights_cache);
+      handle, graph_view, vertex_weights.begin(), src_vertex_weights_cache.mutable_view());
 
     cugraph::update_edge_dst_property(
-      handle, graph_view, vertex_weights.begin(), dst_vertex_weights_cache);
+      handle, graph_view, vertex_weights.begin(), dst_vertex_weights_cache.mutable_view());
 
     rmm::device_uvector<result_t> weighted_averages(
       size_of_the_vertex_partition_assigned_to_this_process, handle.get_stream());
@@ -259,10 +259,10 @@ void perform_example_graph_operations(
                                                                                   graph_view);
 
     cugraph::update_edge_src_property(
-      handle, graph_view, vertex_weights.begin(), src_vertex_weights_cache);
+      handle, graph_view, vertex_weights.begin(), src_vertex_weights_cache.mutable_view());
 
     cugraph::update_edge_dst_property(
-      handle, graph_view, vertex_weights.begin(), dst_vertex_weights_cache);
+      handle, graph_view, vertex_weights.begin(), dst_vertex_weights_cache.mutable_view());
 
     rmm::device_uvector<result_t> weighted_averages(
       size_of_the_vertex_partition_assigned_to_this_process, handle.get_stream());

cpp/examples/developers/vertex_and_edge_partition/vertex_and_edge_partition.cu

@@ -127,7 +127,7 @@ create_graph(raft::handle_t const& handle,
   //
 
   if (multi_gpu) {
-    std::tie(d_edge_srcs, d_edge_dsts, d_edge_wgts, std::ignore, std::ignore) =
+    std::tie(d_edge_srcs, d_edge_dsts, d_edge_wgts, std::ignore, std::ignore, std::ignore) =
       cugraph::shuffle_external_edges<vertex_t, vertex_t, weight_t, int32_t>(handle,
                                                                              std::move(d_edge_srcs),
                                                                              std::move(d_edge_dsts),

cpp/examples/users/multi_gpu_application/mg_graph_algorithms.cpp

@@ -123,7 +123,7 @@ create_graph(raft::handle_t const& handle,
   //
 
   if (multi_gpu) {
-    std::tie(d_edge_srcs, d_edge_dsts, d_edge_wgts, std::ignore, std::ignore) =
+    std::tie(d_edge_srcs, d_edge_dsts, d_edge_wgts, std::ignore, std::ignore, std::ignore) =
       cugraph::shuffle_external_edges<vertex_t, vertex_t, weight_t, int32_t>(handle,
                                                                              std::move(d_edge_srcs),
                                                                              std::move(d_edge_dsts),
@@ -248,9 +248,8 @@ void run_graph_algorithms(
                             std::cout);
 }
 
-int main(int argc, char** argv)
+void run_tests()
 {
-  initialize_mpi_and_set_device(argc, argv);
   std::unique_ptr<raft::handle_t> handle = initialize_mg_handle();
 
   //
@@ -279,6 +278,7 @@ int main(int argc, char** argv)
       std::move(std::make_optional(edge_wgts)),
       renumber,
       is_symmetric);
+
   // Non-owning view of the graph object
   auto graph_view = graph.view();
 
@@ -292,5 +292,14 @@ int main(int argc, char** argv)
   run_graph_algorithms<vertex_t, edge_t, weight_t, store_transposed, multi_gpu>(
     *handle, graph_view, edge_weight_view);
 
+  handle.release();
+}
+
+int main(int argc, char** argv)
+{
+  initialize_mpi_and_set_device(argc, argv);
+
+  run_tests();
+
   RAFT_MPI_TRY(MPI_Finalize());
 }

cpp/include/cugraph/graph_functions.hpp

@@ -1178,7 +1178,8 @@ std::tuple<rmm::device_uvector<vertex_t>,
            rmm::device_uvector<vertex_t>,
            std::optional<rmm::device_uvector<weight_t>>,
            std::optional<rmm::device_uvector<edge_t>>,
-           std::optional<rmm::device_uvector<edge_type_t>>>
+           std::optional<rmm::device_uvector<edge_type_t>>,
+           std::vector<size_t>>
 shuffle_external_edges(raft::handle_t const& handle,
                        rmm::device_uvector<vertex_t>&& edge_srcs,
                        rmm::device_uvector<vertex_t>&& edge_dsts,