Ifpack2_Utilities.hpp

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// @HEADER
// *****************************************************************************
//       Ifpack2: Templated Object-Oriented Algebraic Preconditioner Package
//
// Copyright 2009 NTESS and the Ifpack2 contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef IFPACK2_UTILITIES_HPP
#define IFPACK2_UTILITIES_HPP

#include "Ifpack2_ConfigDefs.hpp"

#include "Teuchos_RefCountPtr.hpp"
#include "Teuchos_ScalarTraits.hpp"

#include "Tpetra_ConfigDefs.hpp"
#include "Tpetra_CrsGraph.hpp"


namespace Ifpack2 {

namespace Details {

template <class graph_type>
Teuchos::RCP<Tpetra::CrsGraph<typename graph_type::local_ordinal_type, typename graph_type::global_ordinal_type, typename graph_type::node_type> >
computeDiagonalGraph(graph_type const& graph) {
  typedef typename graph_type::local_ordinal_type LO;
  typedef typename graph_type::global_ordinal_type GO;
  typedef typename graph_type::node_type NO;
  typedef Tpetra::Map<LO, GO, NO> map_type;
  typedef Tpetra::CrsGraph<LO, GO, NO> crs_graph_type;

  const size_t maxDiagEntPerRow = 1;
  // NOTE (mfh 12 Aug 2014) We could also pass in the column Map
  // here.  However, we still would have to do LID->GID lookups to
  // make sure that we are using the correct diagonal column
  // indices, so it probably wouldn't help much.
  Teuchos::RCP<graph_type> diagonalGraph;
  diagonalGraph              = Teuchos::rcp(new crs_graph_type(graph.getRowMap(), maxDiagEntPerRow));
  const map_type& meshRowMap = *(graph.getRowMap());

  Teuchos::Array<GO> diagGblColInds(maxDiagEntPerRow);

  for (LO lclRowInd = meshRowMap.getMinLocalIndex(); lclRowInd <= meshRowMap.getMaxLocalIndex(); ++lclRowInd) {
    const GO gblRowInd = meshRowMap.getGlobalElement(lclRowInd);
    diagGblColInds[0]  = gblRowInd;
    diagonalGraph->insertGlobalIndices(gblRowInd, diagGblColInds());
  }

  diagonalGraph->fillComplete(graph.getDomainMap(), graph.getRangeMap());
  return diagonalGraph;
}

std::string canonicalize(const std::string& precType);

}  // namespace Details

}  // namespace Ifpack2

#endif  // IFPACK2_UTILITIES_HPP