Tpetra_Details_getGraphOffRankOffsets_def.hpp

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// @HEADER
// *****************************************************************************
//          Tpetra: Templated Linear Algebra Services Package
//
// Copyright 2008 NTESS and the Tpetra contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef TPETRA_DETAILS_GETGRAPHOFFRANKOFFSETS_DEF_HPP
#define TPETRA_DETAILS_GETGRAPHOFFRANKOFFSETS_DEF_HPP


#include "Tpetra_Details_OrdinalTraits.hpp"
#include "Tpetra_Map.hpp"
#include "KokkosSparse_findRelOffset.hpp"

namespace Tpetra {
namespace Details {
namespace Impl {

template<class LO,
         class GO,
         class Node,
         class OffsetType>
GetGraphOffRankOffsets<LO, GO, Node, OffsetType>::
GetGraphOffRankOffsets (const offsets_type& OffRankOffsets,
                        const local_map_type& lclColMap,
                        const local_map_type& lclDomMap,
                        const row_offsets_type& ptr,
                        const lcl_col_inds_type& ind) :
  OffRankOffsets_ (OffRankOffsets),
  lclColMap_ (lclColMap),
  lclDomMap_ (lclDomMap),
  ptr_ (ptr),
  ind_ (ind)
{
  typedef typename device_type::execution_space execution_space;
  typedef Kokkos::RangePolicy<execution_space, LO> policy_type;

  lclNumRows_ = ptr.extent(0)-1;
  policy_type range (0, ptr.extent(0));
  Kokkos::parallel_for (range, *this);
}

template<class LO,
         class GO,
         class Node,
         class OffsetType>
KOKKOS_FUNCTION void
GetGraphOffRankOffsets<LO, GO, Node, OffsetType>::
operator() (const LO& lclRowInd) const
{
  const LO INVALID =
    Tpetra::Details::OrdinalTraits<LO>::invalid ();

  if (lclRowInd == lclNumRows_)
    OffRankOffsets_[lclRowInd] = ptr_[lclRowInd];
  else {
    // TODO: use parallel reduce
    size_t offset = ptr_[lclRowInd+1];
    for (size_t j = ptr_[lclRowInd]; j < ptr_[lclRowInd+1]; j++) {
      const LO lclColInd = ind_[j];
      const GO gblColInd = lclColMap_.getGlobalElement (lclColInd);
      const LO lclDomInd = lclDomMap_.getLocalElement (gblColInd);
      if ((lclDomInd == INVALID) && (j < offset))
        offset = j;
    }
    OffRankOffsets_[lclRowInd] = offset;
  }
}

} // namespace Impl
} // namespace Details
} // namespace Tpetra

// Explicit template instantiation macro for
// Tpetra::Details::Impl::GetGraphOffRankOffsets.  NOT FOR USERS!!!  Must
// be used inside the Tpetra namespace.
#define TPETRA_DETAILS_IMPL_GETGRAPHOFFRANKOFFSETS_INSTANT( LO, GO, NODE ) \
  template class Details::Impl::GetGraphOffRankOffsets< LO, GO, NODE::device_type >;

#endif // TPETRA_DETAILS_GETGRAPHOFFRANKOFFSETS_DEF_HPP