MueLu_InterfaceAggregationAlgorithm_def.hpp

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/*
 * MueLu_OnePtAggregationAlgorithm_def.hpp
 *
 *  Created on: Sep 18, 2012
 *      Author: Tobias Wiesner
 */
 
#ifndef MUELU_INTERFACEAGGREGATIONALGORITHM_DEF_HPP_
#define MUELU_INTERFACEAGGREGATIONALGORITHM_DEF_HPP_
 
#include <Teuchos_Comm.hpp>
#include <Teuchos_CommHelpers.hpp>
 
#include <Xpetra_Vector.hpp>
 
#include "MueLu_InterfaceAggregationAlgorithm_decl.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>
InterfaceAggregationAlgorithm<LocalOrdinal, GlobalOrdinal, Node>::InterfaceAggregationAlgorithm(RCP<const FactoryBase> const &/* graphFact */)
{
}
 
template <class LocalOrdinal, class GlobalOrdinal, class Node>
void InterfaceAggregationAlgorithm<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 numLocalAggregates = aggregates.GetNumAggregates();    // number of local aggregates on current proc
 
  // main loop over all local rows of graph(A)
  for(int iNode1 = 0; iNode1 < nRows; ++iNode1) {
 
    if (aggStat[iNode1] == INTERFACE) {
 
      aggregates.SetIsRoot(iNode1);    // mark iNode1 as root node for new aggregate 'agg'
      int aggIndex = numLocalAggregates;
      std::vector<int> aggList;
      aggList.push_back(iNode1);
      ArrayView<const LO> neighOfINode = graph.getNeighborVertices(iNode1);
 
      for(int j = 0; j < neighOfINode.size(); ++j) {
        LO neigh = neighOfINode[j];
        if(neigh != iNode1 && graph.isLocalNeighborVertex(neigh)) {
          if(aggStat[neigh] != AGGREGATED && aggStat[neigh] != INTERFACE &&
             aggStat[neigh] != IGNORED) {
            aggList.push_back(neigh);
          }
        }
      }
 
      for (size_t k = 0; k < aggList.size(); k++) {
        aggStat[aggList[k]]      = AGGREGATED;
        vertex2AggId[aggList[k]] = aggIndex;
        procWinner[aggList[k]]   = myRank;
      }
      ++numLocalAggregates;
      numNonAggregatedNodes -= aggList.size();
    }
 
  } // end for
 
  // update aggregate object
  aggregates.SetNumAggregates(numLocalAggregates);
}
 
} // end namespace
 
 
#endif /* MUELU_INTERFACEAGGREGATIONALGORITHM_DEF_HPP_ */