mpi: contiguous Irecv wrapper

src/KokkosComm_traits.hpp

@@ -32,6 +32,7 @@ struct Traits {
 /*! \brief This can be specialized to do custom behavior for a particular view*/
 template <KokkosView View>
 struct Traits<View> {
+  // product of extents is span
   static bool is_contiguous(const View &v) { return v.span_is_contiguous(); }
 
   static auto data_handle(const View &v) { return v.data(); }

src/impl/KokkosComm_irecv.hpp

@@ -0,0 +1,47 @@
+//@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
+
+#pragma once
+
+#include <memory>
+
+#include <Kokkos_Core.hpp>
+
+#include "KokkosComm_pack_traits.hpp"
+#include "KokkosComm_traits.hpp"
+
+// impl
+#include "KokkosComm_include_mpi.hpp"
+
+namespace KokkosComm::Impl {
+
+// low-level API
+template <KokkosView RecvView>
+void irecv(RecvView &rv, int src, int tag, MPI_Comm comm, MPI_Request &req) {
+  Kokkos::Tools::pushRegion("KokkosComm::Impl::irecv");
+
+  using KCT = KokkosComm::Traits<RecvView>;
+
+  if (KCT::is_contiguous(rv)) {
+    using RecvScalar = typename RecvView::value_type;
+    MPI_Irecv(KCT::data_handle(rv), KCT::span(rv), mpi_type_v<RecvScalar>, src, tag, comm, &req);
+  } else {
+    throw std::runtime_error("Only contiguous irecv viewsupported");
+  }
+
+  Kokkos::Tools::popRegion();
+}
+}  // namespace KokkosComm::Impl

unit_tests/CMakeLists.txt

@@ -44,6 +44,7 @@ target_link_libraries(test-mpi MPI::MPI_CXX)
 # Kokkos Comm tests
 add_executable(test-main test_main.cpp
   test_gtest_mpi.cpp
+  test_isendirecv.cpp
   test_isendrecv.cpp
   test_reduce.cpp
   test_sendrecv.cpp

unit_tests/test_isendirecv.cpp

@@ -0,0 +1,109 @@
+//@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 <gtest/gtest.h>
+
+#include "KokkosComm.hpp"
+#include "KokkosComm_irecv.hpp"
+
+#include "view_builder.hpp"
+
+namespace {
+
+template <typename T>
+class IsendIrecv : public testing::Test {
+ public:
+  using Scalar = T;
+};
+
+using ScalarTypes =
+    ::testing::Types<float, double, Kokkos::complex<float>, Kokkos::complex<double>, int, unsigned, int64_t, size_t>;
+TYPED_TEST_SUITE(IsendIrecv, ScalarTypes);
+
+template <KokkosComm::KokkosView View1D>
+void test_1d(const View1D &a) {
+  static_assert(View1D::rank == 1, "");
+  using Scalar = typename View1D::non_const_value_type;
+
+  int rank, size;
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+  MPI_Comm_size(MPI_COMM_WORLD, &size);
+  if (size < 2) {
+    GTEST_SKIP() << "Requires >= 2 ranks (" << size << " provided)";
+  }
+
+  if (0 == rank) {
+    int dst = 1;
+    Kokkos::parallel_for(
+        a.extent(0), KOKKOS_LAMBDA(const int i) { a(i) = i; });
+    KokkosComm::Req req = KokkosComm::isend(Kokkos::DefaultExecutionSpace(), a, dst, 0, MPI_COMM_WORLD);
+    req.wait();
+  } else if (1 == rank) {
+    int src = 0;
+    MPI_Request req;
+    KokkosComm::Impl::irecv(a, src, 0, MPI_COMM_WORLD, req);
+    MPI_Wait(&req, MPI_STATUS_IGNORE);
+    int errs;
+    Kokkos::parallel_reduce(
+        a.extent(0), KOKKOS_LAMBDA(const int &i, int &lsum) { lsum += a(i) != Scalar(i); }, errs);
+    ASSERT_EQ(errs, 0);
+  }
+}
+
+template <KokkosComm::KokkosView View2D>
+void test_2d(const View2D &a) {
+  static_assert(View2D::rank == 2, "");
+  using Scalar = typename View2D::non_const_value_type;
+
+  int rank, size;
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+  MPI_Comm_size(MPI_COMM_WORLD, &size);
+  if (size < 2) {
+    GTEST_SKIP() << "Requires >= 2 ranks (" << size << " provided)";
+  }
+
+  using Policy = Kokkos::MDRangePolicy<Kokkos::Rank<2>>;
+  Policy policy({0, 0}, {a.extent(0), a.extent(1)});
+
+  if (0 == rank) {
+    int dst = 1;
+    Kokkos::parallel_for(
+        policy, KOKKOS_LAMBDA(int i, int j) { a(i, j) = i * a.extent(0) + j; });
+    KokkosComm::Req req = KokkosComm::isend(Kokkos::DefaultExecutionSpace(), a, dst, 0, MPI_COMM_WORLD);
+    req.wait();
+  } else if (1 == rank) {
+    int src = 0;
+    MPI_Request req;
+    KokkosComm::Impl::irecv(a, src, 0, MPI_COMM_WORLD, req);
+    MPI_Wait(&req, MPI_STATUS_IGNORE);
+    int errs;
+    Kokkos::parallel_reduce(
+        policy, KOKKOS_LAMBDA(int i, int j, int &lsum) { lsum += a(i, j) != Scalar(i * a.extent(0) + j); }, errs);
+    ASSERT_EQ(errs, 0);
+  }
+}
+
+TYPED_TEST(IsendIrecv, 1D_contig) {
+  auto a = ViewBuilder<typename TestFixture::Scalar, 1>::view(contig{}, "a", 1013);
+  test_1d(a);
+}
+
+TYPED_TEST(IsendIrecv, 2D_contig) {
+  auto a = ViewBuilder<typename TestFixture::Scalar, 2>::view(contig{}, "a", 137, 17);
+  test_2d(a);
+}
+
+}  // namespace

unit_tests/test_main.cpp

@@ -88,7 +88,6 @@ int main(int argc, char *argv[]) {
   if (0 == rank) {
     std::cerr << argv[0] << " (KokkosComm " << KOKKOSCOMM_VERSION_MAJOR << "." << KOKKOSCOMM_VERSION_MINOR << "."
               << KOKKOSCOMM_VERSION_PATCH << ")\n";
-    std::cerr << "size=" << size << "\n";
   }
 
   Kokkos::initialize();

unit_tests/view_builder.hpp

@@ -0,0 +1,46 @@
+//@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
+
+#pragma once
+
+#include <Kokkos_Core.hpp>
+
+struct contig {};
+struct noncontig {};
+
+template <typename T, int RANK>
+struct ViewBuilder;
+
+template <typename T>
+struct ViewBuilder<T, 1> {
+  static auto view(noncontig, const std::string &name, int e0) {
+    // this is C-style layout, i.e. v(0,0) is next to v(0,1)
+    Kokkos::View<T **, Kokkos::LayoutRight> v(name, e0, 2);
+    return Kokkos::subview(v, Kokkos::ALL, 1);  // take column 1
+  }
+
+  static auto view(contig, const std::string &name, int e0) { return Kokkos::View<T *>(name, e0); }
+};
+
+template <typename T>
+struct ViewBuilder<T, 2> {
+  static auto view(noncontig, const std::string &name, int e0, int e1) {
+    Kokkos::View<T ***, Kokkos::LayoutRight> v(name, e0, e1, 2);
+    return Kokkos::subview(v, Kokkos::ALL, Kokkos::ALL, 1);
+  }
+
+  static auto view(contig, const std::string &name, int e0, int e1) { return Kokkos::View<T **>(name, e0, e1); }
+};