Tpetra_Details_LocalMap.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_LOCALMAP_HPP
#define TPETRA_DETAILS_LOCALMAP_HPP


#include "Tpetra_Details_FixedHashTable.hpp"
// #include "Tpetra_Details_OrdinalTraits.hpp" // comes in above
// #include "Kokkos_Core.hpp" // comes in above
#include "Tpetra_Details_LocalMap_fwd.hpp"

namespace Tpetra {
namespace Details {

template<class LocalOrdinal, class GlobalOrdinal, class DeviceType>
class LocalMap {
public:
  using local_ordinal_type = LocalOrdinal;

  using global_ordinal_type = GlobalOrdinal;

  using device_type = DeviceType;

  using execution_space = typename device_type::execution_space;

  using memory_space = typename device_type::memory_space;

  KOKKOS_DEFAULTED_FUNCTION LocalMap() = default;

  LocalMap (const ::Tpetra::Details::FixedHashTable<GlobalOrdinal, LocalOrdinal, device_type>& glMap,
            const ::Kokkos::View<const GlobalOrdinal*, ::Kokkos::LayoutLeft, device_type>& lgMap,
            const GlobalOrdinal indexBase,
            const GlobalOrdinal myMinGid,
            const GlobalOrdinal myMaxGid,
            const GlobalOrdinal firstContiguousGid,
            const GlobalOrdinal lastContiguousGid,
            const LocalOrdinal numLocalElements,
            const bool contiguous) :
    glMap_ (glMap),
    lgMap_ (lgMap),
    indexBase_ (indexBase),
    myMinGid_ (myMinGid),
    myMaxGid_ (myMaxGid),
    firstContiguousGid_ (firstContiguousGid),
    lastContiguousGid_ (lastContiguousGid),
    numLocalElements_ (numLocalElements),
    contiguous_ (contiguous)
  {}

  KOKKOS_INLINE_FUNCTION LocalOrdinal getLocalNumElements () const {
    return numLocalElements_;
  }

  KOKKOS_INLINE_FUNCTION GlobalOrdinal getIndexBase () const {
    return indexBase_;
  }

  KOKKOS_INLINE_FUNCTION bool isContiguous () const {
    return contiguous_;
  }

  KOKKOS_INLINE_FUNCTION LocalOrdinal getMinLocalIndex () const {
    return 0;
  }

  KOKKOS_INLINE_FUNCTION LocalOrdinal
  getMaxLocalIndex () const
  {
    if (numLocalElements_ == 0) {
      return ::Tpetra::Details::OrdinalTraits<LocalOrdinal>::invalid ();
    } else { // Local indices are always zero-based.
      return static_cast<LocalOrdinal> (numLocalElements_ - 1);
    }
  }

  KOKKOS_INLINE_FUNCTION GlobalOrdinal getMinGlobalIndex () const {
    return myMinGid_;
  }

  KOKKOS_INLINE_FUNCTION GlobalOrdinal getMaxGlobalIndex () const {
    return myMaxGid_;
  }

  KOKKOS_INLINE_FUNCTION LocalOrdinal
  getLocalElement (const GlobalOrdinal globalIndex) const
  {
    if (contiguous_) {
      if (globalIndex < myMinGid_ || globalIndex > myMaxGid_) {
        return ::Tpetra::Details::OrdinalTraits<LocalOrdinal>::invalid ();
      }
      return static_cast<LocalOrdinal> (globalIndex - myMinGid_);
    }
    else if (globalIndex >= firstContiguousGid_ &&
             globalIndex <= lastContiguousGid_) {
      return static_cast<LocalOrdinal> (globalIndex - firstContiguousGid_);
    }
    else {
      // If the given global index is not in the table, this returns
      // the same value as OrdinalTraits<LocalOrdinal>::invalid().
      return glMap_.get (globalIndex);
    }
  }

  KOKKOS_INLINE_FUNCTION GlobalOrdinal
  getGlobalElement (const LocalOrdinal localIndex) const
  {
    if (localIndex < getMinLocalIndex () || localIndex > getMaxLocalIndex ()) {
      return ::Tpetra::Details::OrdinalTraits<GlobalOrdinal>::invalid ();
    }
    if (isContiguous ()) {
      return getMinGlobalIndex () + localIndex;
    }
    else {
      return lgMap_(localIndex);
    }
  }

private:
  ::Tpetra::Details::FixedHashTable<GlobalOrdinal, LocalOrdinal, device_type> glMap_;
  ::Kokkos::View<const GlobalOrdinal*, ::Kokkos::LayoutLeft, device_type> lgMap_;

  GlobalOrdinal indexBase_          = 0;
  GlobalOrdinal myMinGid_           = Tpetra::Details::OrdinalTraits<GlobalOrdinal>::invalid();
  GlobalOrdinal myMaxGid_           = Tpetra::Details::OrdinalTraits<GlobalOrdinal>::invalid();
  GlobalOrdinal firstContiguousGid_ = Tpetra::Details::OrdinalTraits<GlobalOrdinal>::invalid();
  GlobalOrdinal lastContiguousGid_  = Tpetra::Details::OrdinalTraits<GlobalOrdinal>::invalid();
  LocalOrdinal numLocalElements_    = 0;
  bool contiguous_                  = false;
};

} // namespace Details
} // namespace Tpetra

#endif // TPETRA_DETAILS_LOCALMAP_HPP