Tpetra parallel linear algebra Version of the Day
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Tpetra_Details_getEntryOnHost.hpp
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41
42#ifndef TPETRA_DETAILS_GETENTRYONHOST_HPP
43#define TPETRA_DETAILS_GETENTRYONHOST_HPP
44
50
51#include "TpetraCore_config.h"
52#include "Kokkos_Core.hpp"
53
54namespace Tpetra {
55namespace Details {
56
57template<class ViewType,
58 class IndexType>
59typename ViewType::non_const_value_type
60getEntryOnHost (const ViewType& x,
61 const IndexType ind)
62{
63 using execution_space = typename ViewType::execution_space;
64 static_assert (ViewType::Rank == 1, "x must be a rank-1 Kokkos::View.");
65 // Get a 0-D subview of the entry of the array, and copy to host scalar.
66 typename ViewType::non_const_value_type val;
67 // DEEP_COPY REVIEW - DEVICE-TO-VALUE
68 Kokkos::deep_copy(execution_space(), val, Kokkos::subview(x, ind));
69 return val;
70}
71
72template<class ViewType,
73 class IndexType>
74typename ViewType::HostMirror::const_type
75getEntriesOnHost (const ViewType& x,
76 const IndexType ind,
77 const int count)
78{
79 static_assert (ViewType::Rank == 1, "x must be a rank-1 Kokkos::View.");
80 // Get a 1-D subview of the entry of the array, and copy to host.
81 auto subview = Kokkos::subview(x, Kokkos::make_pair(ind, ind + count));
82 return Kokkos::create_mirror_view_and_copy(typename ViewType::HostMirror::memory_space(), subview);
83}
84
85} // namespace Details
86} // namespace Tpetra
87
88#endif // TPETRA_DETAILS_GETENTRYONHOST_HPP
Implementation details of Tpetra.
Namespace Tpetra contains the class and methods constituting the Tpetra library.