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