MueLu_OnePtAggregationAlgorithm_def.hpp

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/*
 * MueLu_OnePtAggregationAlgorithm_def.hpp
 *
 *  Created on: Sep 18, 2012
 *      Author: Tobias Wiesner
 */

#ifndef MUELU_ONEPTAGGREGATIONALGORITHM_DEF_HPP_
#define MUELU_ONEPTAGGREGATIONALGORITHM_DEF_HPP_

#include <Teuchos_Comm.hpp>
#include <Teuchos_CommHelpers.hpp>

#include <Xpetra_Vector.hpp>

#include "MueLu_OnePtAggregationAlgorithm.hpp"

//#include "MueLu_Graph.hpp"
#include "MueLu_GraphBase.hpp"
#include "MueLu_Aggregates.hpp"
#include "MueLu_Exceptions.hpp"
#include "MueLu_Monitor.hpp"

namespace MueLu {

template <class LocalOrdinal, class GlobalOrdinal, class Node>
OnePtAggregationAlgorithm<LocalOrdinal, GlobalOrdinal, Node>::OnePtAggregationAlgorithm(RCP<const FactoryBase> const &/* graphFact */)
{
}

template <class LocalOrdinal, class GlobalOrdinal, class Node>
void OnePtAggregationAlgorithm<LocalOrdinal, GlobalOrdinal, Node>::BuildAggregates(Teuchos::ParameterList const & /* params */, GraphBase const & graph, Aggregates & aggregates, std::vector<unsigned>& aggStat, LO& numNonAggregatedNodes) const {
  Monitor m(*this, "BuildAggregates");

  const LocalOrdinal nRows = graph.GetNodeNumVertices();
  const int myRank = graph.GetComm()->getRank();

  // vertex ids for output
  Teuchos::ArrayRCP<LocalOrdinal> vertex2AggId = aggregates.GetVertex2AggId()->getDataNonConst(0);
  Teuchos::ArrayRCP<LocalOrdinal> procWinner   = aggregates.GetProcWinner()->getDataNonConst(0);

  // some internal variables
  LocalOrdinal nLocalAggregates = aggregates.GetNumAggregates();    // number of local aggregates on current proc
  LocalOrdinal iNode1  = 0;        // current node

  // main loop over all local rows of graph(A)
  while (iNode1 < nRows) {

    if (aggStat[iNode1] == ONEPT) {

      aggregates.SetIsRoot(iNode1);    // mark iNode1 as root node for new aggregate 'ag'
      std::vector<int> aggList;
      aggList.push_back(iNode1);
      int aggIndex = nLocalAggregates++;

      for (size_t k = 0; k < aggList.size(); k++) {
        aggStat[aggList[k]] = IGNORED;
        vertex2AggId[aggList[k]] = aggIndex;
        procWinner[aggList[k]] = myRank;
      }
      numNonAggregatedNodes -= aggList.size();
    }

    iNode1++;
  } // end while

  // update aggregate object
  aggregates.SetNumAggregates(nLocalAggregates);
}

} // end namespace


#endif /* MUELU_ONEPTAGGREGATIONALGORITHM_DEF_HPP_ */