Update Kokkos library in LAMMPS to v4.0

lib/kokkos/core/unit_test/TestLegionInitialization.cpp

@@ -0,0 +1,65 @@
+//@HEADER
+// ************************************************************************
+//
+//                        Kokkos v. 4.0
+//       Copyright (2022) National Technology & Engineering
+//               Solutions of Sandia, LLC (NTESS).
+//
+// Under the terms of Contract DE-NA0003525 with NTESS,
+// the U.S. Government retains certain rights in this software.
+//
+// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
+// See https://kokkos.org/LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//@HEADER
+
+#include <Kokkos_Core.hpp>
+#include <gtest/gtest.h>
+
+namespace {
+
+struct ReductionFunctor {
+  Kokkos::View<int*> d;
+
+  KOKKOS_FUNCTION void operator()(int i, int& sum) const { sum += d(i); }
+};
+
+// The purpose of this test is to mimic Legion's use case of initializing and
+// finalizing individual backends
+TEST(initialization, legion_initialization) {
+  Kokkos::InitializationSettings kokkos_init_settings;
+
+  Kokkos::Impl::pre_initialize(kokkos_init_settings);
+
+  // We need to have a host execution space initialized first.
+  Kokkos::DefaultHostExecutionSpace::impl_initialize(kokkos_init_settings);
+
+  if (!std::is_same_v<Kokkos::DefaultExecutionSpace,
+                      Kokkos::DefaultHostExecutionSpace>)
+    Kokkos::DefaultExecutionSpace::impl_initialize(kokkos_init_settings);
+
+  Kokkos::Impl::post_initialize(kokkos_init_settings);
+
+  EXPECT_TRUE(Kokkos::is_initialized());
+
+  {
+    Kokkos::View<int*> d("d", 1000);
+    Kokkos::deep_copy(d, 1);
+    int result;
+    Kokkos::parallel_reduce("TestRed", d.extent(0), ReductionFunctor{d},
+                            result);
+    EXPECT_EQ(result, d.extent_int(0));
+  }
+
+  Kokkos::Impl::pre_finalize();
+  if (!std::is_same_v<Kokkos::DefaultExecutionSpace,
+                      Kokkos::DefaultHostExecutionSpace>)
+    Kokkos::DefaultExecutionSpace::impl_finalize();
+  Kokkos::DefaultHostExecutionSpace::impl_finalize();
+  Kokkos::Impl::post_finalize();
+
+  EXPECT_FALSE(Kokkos::is_initialized());
+  EXPECT_TRUE(Kokkos::is_finalized());
+}
+}  // namespace