Fix Tpetra vector compression state after add() into locally owned entry

Fix Tpetra vector compression state based on the presence of non-local entries

add a test for Tpetra vector addition into both owned and nonlocal entries

doc/news/changes/minor/20240828Shi

@@ -0,0 +1,5 @@
+Fix: Add the missing `compressed = false` in TpetraWrappers::Vector::add()
+function to ensure distributed Tpetra vector with writable nonlocal
+entries will always be non-compressed after any entry addition.
+<br>
+(Qingyuan Shi, 2024/08/28)

include/deal.II/lac/trilinos_tpetra_vector.h

@@ -1167,6 +1167,12 @@ namespace LinearAlgebra
               local_row != Teuchos::OrdinalTraits<int>::invalid())
             {
               vector_1d_local(local_row) += values[i];
+
+              // Set the compressed state to false only if there is nonlocal
+              // part in this distributed vector, otherwise it's always
+              // compressed.
+              if (nonlocal_vector.get() != nullptr)
+                compressed = false;
             }
           else
             {
@@ -1285,6 +1291,12 @@ namespace LinearAlgebra
               local_row != Teuchos::OrdinalTraits<int>::invalid())
             {
               vector_1d_local(local_row) = values[i];
+
+              // Set the compressed state to false only if there is nonlocal
+              // part in this distributed vector, otherwise it's always
+              // compressed.
+              if (nonlocal_vector.get() != nullptr)
+                compressed = false;
             }
           else
             {

tests/trilinos_tpetra/vector_nonlocal_addition.cc

@@ -0,0 +1,186 @@
+// ------------------------------------------------------------------------
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// Copyright (C) 2004 - 2024 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// Part of the source code is dual licensed under Apache-2.0 WITH
+// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
+// governing the source code and code contributions can be found in
+// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
+//
+// ------------------------------------------------------------------------
+
+
+
+// Test distributed vector operations across multiple processes with non-local
+// entries to verify correct handling and compression states.
+
+#include <deal.II/base/index_set.h>
+#include <deal.II/base/utilities.h>
+
+#include <deal.II/lac/trilinos_tpetra_vector.h>
+
+#include <iostream>
+#include <vector>
+
+#include "../tests.h"
+
+
+void
+test()
+{
+  unsigned int my_rank = Utilities::MPI::this_mpi_process(MPI_COMM_WORLD);
+  unsigned int n_procs = Utilities::MPI::n_mpi_processes(MPI_COMM_WORLD);
+
+
+  IndexSet locally_owned(8);
+  IndexSet locally_relevant(8);
+
+  // Distribution of vector entries across processes:
+  // Process 0 and Process 1 have non-local entries, while Process 2 does not.
+
+  // Entry Index  |  Process Distribution  |  Owned by
+  // ------------ | ----------------------| ----------
+  //  0           |      0                 |     0
+  //  1           |      0                 |     0
+  //  2           |      0, 1              |     0
+  //  3           |      0, 1              |     1
+  //  4           |         1              |     1
+  //  5           |         1, 2           |     2
+  //  6           |            2           |     2
+  //  7           |            2           |     2
+
+
+  if (my_rank == 0)
+    {
+      locally_owned.add_range(0, 3);
+      locally_relevant.add_range(0, 4);
+    }
+  if (my_rank == 1)
+    {
+      locally_owned.add_range(3, 5);
+      locally_relevant.add_range(2, 6);
+    }
+  if (my_rank == 2)
+    {
+      // no nonlocal entries on rank 2
+      locally_owned.add_range(5, 8);
+      locally_relevant.add_range(5, 8);
+    }
+  locally_owned.compress();
+  locally_relevant.compress();
+
+  // Create a vector with writable entries
+  LinearAlgebra::TpetraWrappers::Vector<double, MemorySpace::Default>
+    vector_with_nonlocal_entries;
+
+  vector_with_nonlocal_entries.reinit(locally_owned,
+                                      locally_relevant,
+                                      MPI_COMM_WORLD,
+                                      true);
+
+  vector_with_nonlocal_entries = 0.0;
+
+  if (my_rank == 0)
+    {
+      // Add to both local and non-local parts
+      vector_with_nonlocal_entries[0] += 1.0;
+      vector_with_nonlocal_entries[1] += 1.0;
+      vector_with_nonlocal_entries[2] += 1.0;
+      vector_with_nonlocal_entries[3] += 1.0;
+    }
+  if (my_rank == 1)
+    {
+      // Add to both local and non-local parts
+      vector_with_nonlocal_entries[2] += 2.0;
+      vector_with_nonlocal_entries[3] += 2.0;
+      vector_with_nonlocal_entries[4] += 2.0;
+      vector_with_nonlocal_entries[5] += 2.0;
+    }
+  if (my_rank == 2)
+    {
+      // Add to only local part, there's no nonlocal part on rank 2
+      vector_with_nonlocal_entries[5] += 3.0;
+      vector_with_nonlocal_entries[6] += 3.0;
+      vector_with_nonlocal_entries[7] += 3.0;
+    }
+  vector_with_nonlocal_entries.compress(VectorOperation::add);
+
+  // Expected Results:
+  // Entry Index  |  Additions     |  Result
+  // ------------ | -------------- | -------
+  //  0           |   +1           |   1.0
+  //  1           |   +1           |   1.0
+  //  2           |   +1, +2       |   3.0
+  //  3           |   +1, +2       |   3.0
+  //  4           |       +2       |   2.0
+  //  5           |       +2, +3   |   5.0
+  //  6           |           +3   |   3.0
+  //  7           |           +3   |   3.0
+
+  // Check the results on each process
+  if (my_rank == 0)
+    {
+      AssertThrow((vector_with_nonlocal_entries[0] == 1.0), ExcInternalError());
+      AssertThrow((vector_with_nonlocal_entries[1] == 1.0), ExcInternalError());
+      AssertThrow((vector_with_nonlocal_entries[2] == 3.0), ExcInternalError());
+    }
+  if (my_rank == 1)
+    {
+      AssertThrow((vector_with_nonlocal_entries[3] == 3.0), ExcInternalError());
+      AssertThrow((vector_with_nonlocal_entries[4] == 2.0), ExcInternalError());
+    }
+  if (my_rank == 2)
+    {
+      AssertThrow((vector_with_nonlocal_entries[5] == 5.0), ExcInternalError());
+      AssertThrow((vector_with_nonlocal_entries[6] == 3.0), ExcInternalError());
+      AssertThrow((vector_with_nonlocal_entries[7] == 3.0), ExcInternalError());
+    }
+
+  deallog << "OK" << std::endl;
+}
+
+
+
+int
+main(int argc, char **argv)
+{
+  initlog();
+
+  Utilities::MPI::MPI_InitFinalize mpi_initialization(
+    argc, argv, testing_max_num_threads());
+
+
+  try
+    {
+      test();
+    }
+  catch (const std::exception &exc)
+    {
+      std::cerr << std::endl
+                << std::endl
+                << "----------------------------------------------------"
+                << std::endl;
+      std::cerr << "Exception on processing: " << std::endl
+                << exc.what() << std::endl
+                << "Aborting!" << std::endl
+                << "----------------------------------------------------"
+                << std::endl;
+
+      return 1;
+    }
+  catch (...)
+    {
+      std::cerr << std::endl
+                << std::endl
+                << "----------------------------------------------------"
+                << std::endl;
+      std::cerr << "Unknown exception!" << std::endl
+                << "Aborting!" << std::endl
+                << "----------------------------------------------------"
+                << std::endl;
+      return 1;
+    };
+}

tests/trilinos_tpetra/vector_nonlocal_addition.mpirun=3.output

@@ -0,0 +1,2 @@
+
+DEAL::OK