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Tpetra_Details_DualViewUtil.hpp
1 // @HEADER
2 // *****************************************************************************
3 // Tpetra: Templated Linear Algebra Services Package
4 //
5 // Copyright 2008 NTESS and the Tpetra contributors.
6 // SPDX-License-Identifier: BSD-3-Clause
7 // *****************************************************************************
8 // @HEADER
9 
10 #ifndef TPETRA_DETAILS_DUALVIEWUTIL_HPP
11 #define TPETRA_DETAILS_DUALVIEWUTIL_HPP
12 
13 #include "TpetraCore_config.h"
14 #include "Kokkos_DualView.hpp"
15 #include "Teuchos_ArrayView.hpp"
16 #include <ostream>
17 #include <string>
18 
20 namespace Tpetra {
21 
24 namespace Details {
25 
29 auto view_alloc_no_init (const std::string& label) ->
30  decltype (Kokkos::view_alloc (label, Kokkos::WithoutInitializing));
31 
36 template<class ElementType, class DeviceType>
37 void
39  (Kokkos::DualView<ElementType*, DeviceType>& dv,
40  const typename Kokkos::DualView<ElementType*, DeviceType>::t_host& hostView)
41 {
42  using execution_space = typename DeviceType::execution_space;
43  using dual_view_type = Kokkos::DualView<ElementType*, DeviceType>;
44 
45  if constexpr(Kokkos::SpaceAccessibility<Kokkos::HostSpace, typename DeviceType::memory_space>::accessible) {
46  // DualView only references one View, so we pass in the same View twice
47  dv = dual_view_type (hostView, hostView);
48  } else {
49  typename Kokkos::DualView<ElementType*, DeviceType>::t_dev devView;
50  if (dv.extent (0) == hostView.extent (0))
51  devView = dv.view_device();
52  else
53  devView = Kokkos::create_mirror_view (DeviceType (), hostView);
54  // DEEP_COPY REVIEW - DEVICE-TO-HOSTMIRROR
55  Kokkos::deep_copy (execution_space(), devView, hostView);
56  dv = dual_view_type (devView, hostView);
57  execution_space().fence();
58  }
59 }
60 
61 template<class ElementType, class DeviceType>
62 void
63 makeDualViewFromArrayView (Kokkos::DualView<ElementType*, DeviceType>& dv,
64  const Teuchos::ArrayView<const ElementType>& av,
65  const std::string& label)
66 {
67  using execution_space = typename DeviceType::execution_space;
68  using dual_view_type = Kokkos::DualView<ElementType*, DeviceType>;
69  using host_view_type = typename dual_view_type::t_host;
70  using const_host_view_type = typename host_view_type::const_type;
71 
72  const auto size = av.size ();
73  const ElementType* ptr = (size == 0) ? nullptr : av.getRawPtr ();
74  const_host_view_type inView (ptr, size);
75  host_view_type hostView (view_alloc_no_init (label), size);
76  // DEEP_COPY REVIEW - DEVICE-TO-HOSTMIRROR
77  Kokkos::deep_copy (execution_space(), hostView, inView);
78 
79  makeDualViewFromOwningHostView (dv, hostView);
80 }
81 
82 template<class ElementType, class DeviceType>
83 void
84 makeDualViewFromVector (Kokkos::DualView<ElementType*, DeviceType>& dv,
85  const std::vector<ElementType>& vec,
86  const std::string& label)
87 {
88  using dual_view_type = Kokkos::DualView<ElementType*, DeviceType>;
89  using execution_space = typename DeviceType::execution_space;
90  using host_view_type = typename dual_view_type::t_host;
91  using const_host_view_type = typename host_view_type::const_type;
92 
93  const auto size = vec.size ();
94  const ElementType* ptr = (size == 0) ? nullptr : vec.data ();
95  const_host_view_type inView (ptr, size);
96  host_view_type hostView (view_alloc_no_init (label), size);
97  // DEEP_COPY REVIEW - DEVICE-TO-HOSTMIRROR
98  Kokkos::deep_copy (execution_space(), hostView, inView);
99 
100  makeDualViewFromOwningHostView (dv, hostView);
101 }
102 
103 template<class ElementType, class DeviceType>
104 void
105 printDualView (std::ostream& out,
106  const Kokkos::DualView<ElementType*, DeviceType>& dv,
107  const std::string& name)
108 {
109  out << name << ": ";
110  const size_t size = size_t (dv.extent (0));
111  const auto hostView = dv.view_host ();
112 
113  out << "[";
114  for (size_t k = 0; k < size; ++k) {
115  out << hostView[k];
116  if (k + size_t (1) < size) {
117  out << ",";
118  }
119  }
120  out << "]";
121 }
122 
123 } // namespace Details
124 
125 } // namespace Tpetra
126 
127 #endif // TPETRA_DETAILS_DUALVIEWUTIL_HPP
void deep_copy(MultiVector< DS, DL, DG, DN > &dst, const MultiVector< SS, SL, SG, SN > &src)
Copy the contents of the MultiVector src into dst.
auto view_alloc_no_init(const std::string &label) ->
Use in place of the string label as the first argument of Kokkos::View&#39;s constructor, in case you want to allocate without initializing.
void makeDualViewFromOwningHostView(Kokkos::DualView< ElementType *, DeviceType > &dv, const typename Kokkos::DualView< ElementType *, DeviceType >::t_host &hostView)
Initialize dv such that its host View is hostView.