Add KokkosExt::{construct_at,destroy_at} (arborx#1084)

Add KokkosExt::{construct_at,destroy_at}

src/kokkos_ext/ArborX_DetailsKokkosExtUninitializedMemoryAlgorithms.hpp

@@ -0,0 +1,36 @@
+/****************************************************************************
+ * Copyright (c) 2024 by the ArborX authors                                 *
+ * All rights reserved.                                                     *
+ *                                                                          *
+ * This file is part of the ArborX library. ArborX is                       *
+ * distributed under a BSD 3-clause license. For the licensing terms see    *
+ * the LICENSE file in the top-level directory.                             *
+ *                                                                          *
+ * SPDX-License-Identifier: BSD-3-Clause                                    *
+ ****************************************************************************/
+#ifndef ARBORX_DETAILS_KOKKOS_EXT_UNINITIALIZED_MEMORY_ALGORITHMS_HPP
+#define ARBORX_DETAILS_KOKKOS_EXT_UNINITIALIZED_MEMORY_ALGORITHMS_HPP
+
+#include <Kokkos_Assert.hpp>
+#include <Kokkos_Macros.hpp>
+
+namespace ArborX::Details::KokkosExt
+{
+
+template <class T, class... Args>
+KOKKOS_FUNCTION constexpr T *construct_at(T *p, Args &&...args)
+{
+  return ::new (const_cast<void *>(static_cast<void const volatile *>(p)))
+      T((Args &&) args...);
+}
+
+template <class T>
+KOKKOS_FUNCTION constexpr void destroy_at(T *p)
+{
+  KOKKOS_ASSERT(p != nullptr);
+  p->~T();
+}
+
+} // namespace ArborX::Details::KokkosExt
+
+#endif

test/CMakeLists.txt

@@ -51,6 +51,7 @@ add_executable(ArborX_Test_DetailsUtils.exe
   tstDetailsUtils.cpp
   tstDetailsKokkosExtStdAlgorithms.cpp
   tstDetailsKokkosExtKernelStdAlgorithms.cpp
+  tstDetailsKokkosExtUninitializedMemoryAlgorithms.cpp
   tstDetailsKokkosExtMinMaxReduce.cpp
   tstDetailsKokkosExtViewHelpers.cpp
   utf_main.cpp

test/tstDetailsKokkosExtUninitializedMemoryAlgorithms.cpp

@@ -0,0 +1,61 @@
+/****************************************************************************
+ * Copyright (c) 2017-2022 by the ArborX authors                            *
+ * All rights reserved.                                                     *
+ *                                                                          *
+ * This file is part of the ArborX library. ArborX is                       *
+ * distributed under a BSD 3-clause license. For the licensing terms see    *
+ * the LICENSE file in the top-level directory.                             *
+ *                                                                          *
+ * SPDX-License-Identifier: BSD-3-Clause                                    *
+ ****************************************************************************/
+
+#include "ArborX_EnableDeviceTypes.hpp" // ARBORX_DEVICE_TYPES
+#include <ArborX_DetailsKokkosExtUninitializedMemoryAlgorithms.hpp>
+#include <ArborX_Exception.hpp>
+
+#include <Kokkos_Core.hpp>
+
+#include "BoostTest_CUDA_clang_workarounds.hpp"
+#include <boost/test/unit_test.hpp>
+
+#define BOOST_TEST_MODULE KokkosExtUninitializedMemoryAlgorithms
+
+namespace tt = boost::test_tools;
+
+struct NoDefaultConstructor
+{
+  int value;
+  KOKKOS_FUNCTION NoDefaultConstructor(int x)
+      : value(x)
+  {}
+  KOKKOS_FUNCTION ~NoDefaultConstructor() { value = -1; }
+};
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(construct_destroy_at, DeviceType,
+                              ARBORX_DEVICE_TYPES)
+{
+  using ArborX::Details::KokkosExt::construct_at;
+  using ArborX::Details::KokkosExt::destroy_at;
+
+  using ExecutionSpace = typename DeviceType::execution_space;
+  ExecutionSpace exec;
+
+  int const n = 2;
+  Kokkos::View<NoDefaultConstructor *, DeviceType> view(
+      Kokkos::view_alloc(exec, Kokkos::WithoutInitializing, "Test::view"), n);
+  Kokkos::parallel_for(
+      "Test::construct", Kokkos::RangePolicy<ExecutionSpace>(exec, 0, n),
+      KOKKOS_LAMBDA(int i) { construct_at(&view(i), i); });
+
+  auto view_host =
+      Kokkos::create_mirror_view_and_copy(Kokkos::HostSpace{}, view);
+  BOOST_TEST(view_host(0).value == 0);
+  BOOST_TEST(view_host(1).value == 1);
+
+  Kokkos::parallel_for(
+      "Test::destroy", Kokkos::RangePolicy<ExecutionSpace>(exec, 0, n),
+      KOKKOS_LAMBDA(int i) { destroy_at(&view(i)); });
+  Kokkos::deep_copy(exec, view_host, view);
+  BOOST_TEST(view_host(0).value == -1);
+  BOOST_TEST(view_host(1).value == -1);
+}