Tpetra parallel linear algebra  Version of the Day
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Pages
Tpetra_Details_get1DConstView.hpp
Go to the documentation of this file.
1 // @HEADER
2 // ***********************************************************************
3 //
4 // Tpetra: Templated Linear Algebra Services Package
5 // Copyright (2008) Sandia Corporation
6 //
7 // Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
8 // the U.S. Government retains certain rights in this software.
9 //
10 // Redistribution and use in source and binary forms, with or without
11 // modification, are permitted provided that the following conditions are
12 // met:
13 //
14 // 1. Redistributions of source code must retain the above copyright
15 // notice, this list of conditions and the following disclaimer.
16 //
17 // 2. Redistributions in binary form must reproduce the above copyright
18 // notice, this list of conditions and the following disclaimer in the
19 // documentation and/or other materials provided with the distribution.
20 //
21 // 3. Neither the name of the Corporation nor the names of the
22 // contributors may be used to endorse or promote products derived from
23 // this software without specific prior written permission.
24 //
25 // THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
26 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
29 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
32 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 //
37 // Questions? Contact Michael A. Heroux (maherou@sandia.gov)
38 //
39 // ************************************************************************
40 // @HEADER
41 
42 #ifndef TPETRA_DETAILS_GET1DCONSTVIEW_HPP
43 #define TPETRA_DETAILS_GET1DCONSTVIEW_HPP
44 
49 
50 #include "Tpetra_ConfigDefs.hpp"
51 #include "Tpetra_Util.hpp"
52 #include "Kokkos_DualView.hpp"
53 #include <Teuchos_Array.hpp>
54 #include <utility>
55 
56 namespace Tpetra {
57 namespace Details {
58 
59 // mfh 28 Apr 2016: Sometimes we have a raw host array, and we need
60 // to make a Kokkos::View out of it that lives in a certain memory
61 // space. We don't want to make a deep copy of the input array if
62 // we don't need to, but if the memory spaces are different, we need
63 // to. The following code does that. The struct is an
64 // implementation detail, and the "free" function
65 // get1DConstViewOfUnmanagedArray is the interface to call.
66 
67 template<class ST, class DT,
68  const bool outputIsHostMemory =
69  std::is_same<typename DT::memory_space, Kokkos::HostSpace>::value>
70 struct Get1DConstViewOfUnmanagedHostArray {};
71 
72 template<class ST, class DT>
73 struct Get1DConstViewOfUnmanagedHostArray<ST, DT, true> {
74  typedef Kokkos::View<const ST*, Kokkos::HostSpace, Kokkos::MemoryUnmanaged> output_view_type;
75 
76  static output_view_type
77  getView (const char /* label */ [], const ST* x_raw, const size_t x_len)
78  {
79  // We can return the input array, wrapped as an unmanaged View.
80  // Ignore the label, since unmanaged Views don't have labels.
81  return output_view_type (x_raw, x_len);
82  }
83 };
84 
85 template<class ST, class DT>
86 struct Get1DConstViewOfUnmanagedHostArray<ST, DT, false> {
87  typedef Kokkos::View<const ST*, Kokkos::HostSpace, Kokkos::MemoryUnmanaged> input_view_type;
88  typedef Kokkos::View<const ST*, DT> output_view_type;
89 
90  static output_view_type
91  getView (const char label[], const ST* x_raw, const size_t x_len)
92  {
93  input_view_type x_in (x_raw, x_len);
94  // The memory spaces are different, so we have to create a new
95  // View which is a deep copy of the input array.
96  //
97  // FIXME (mfh 28 Apr 2016) This needs to be converted to
98  // std::string, else the compiler can't figure out what
99  // constructor we're calling.
100  Kokkos::View<ST*, DT> x_out (std::string (label), x_len);
101  Kokkos::deep_copy (x_out, x_in);
102  return x_out;
103  }
104 };
105 
106 template<class ST, class DT>
107  typename Get1DConstViewOfUnmanagedHostArray<ST, DT>::output_view_type
108 get1DConstViewOfUnmanagedHostArray (const char label[], const ST* x_raw, const size_t x_len)
109 {
110  return Get1DConstViewOfUnmanagedHostArray<ST, DT>::getView (label, x_raw, x_len);
111 }
112 
113 } // namespace Details
114 } // namespace Tpetra
115 
116 #endif // TPETRA_DETAILS_GET1DCONSTVIEW_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.
Stand-alone utility functions and macros.