MueLu_Aggregates_def.hpp

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#ifndef MUELU_AGGREGATES_DEF_HPP
#define MUELU_AGGREGATES_DEF_HPP

#include <Xpetra_Map.hpp>
#include <Xpetra_Vector.hpp>
#include <Xpetra_MultiVector.hpp>
#include <Xpetra_BlockedMultiVector.hpp>
#include <Xpetra_BlockedVector.hpp>
#include <Xpetra_VectorFactory.hpp>
#include <Xpetra_MultiVectorFactory.hpp>

#include "MueLu_Aggregates_decl.hpp"
#include "MueLu_Graph.hpp"
#include "MueLu_Utilities_decl.hpp" // MueLu_sumAll

namespace MueLu {

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Aggregates<LocalOrdinal, GlobalOrdinal, Node>::Aggregates(const GraphBase & graph) {
    nAggregates_  = 0;
    nGlobalAggregates_ = 0;

    vertex2AggId_ = LOMultiVectorFactory::Build(graph.GetImportMap(), 1);
    vertex2AggId_->putScalar(MUELU_UNAGGREGATED);

    procWinner_ = LOVectorFactory::Build(graph.GetImportMap());
    procWinner_->putScalar(MUELU_UNASSIGNED);

    isRoot_ = Teuchos::ArrayRCP<bool>(graph.GetImportMap()->getLocalNumElements(), false);

    // slow but safe, force TentativePFactory to build column map for P itself
    aggregatesIncludeGhosts_ = true;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Aggregates<LocalOrdinal, GlobalOrdinal, Node>::Aggregates(const RCP<const Map> & map) {
    nAggregates_ = 0;
    nGlobalAggregates_ = 0;

    vertex2AggId_ = LOMultiVectorFactory::Build(map, 1);
    vertex2AggId_->putScalar(MUELU_UNAGGREGATED);

    procWinner_ = LOVectorFactory::Build(map);
    procWinner_->putScalar(MUELU_UNASSIGNED);

    isRoot_ = Teuchos::ArrayRCP<bool>(map->getLocalNumElements(), false);

    // slow but safe, force TentativePFactory to build column map for P itself
    aggregatesIncludeGhosts_ = true;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Teuchos::ArrayRCP<LocalOrdinal>  Aggregates<LocalOrdinal, GlobalOrdinal, Node>::ComputeAggregateSizes(bool forceRecompute) const {

    if (aggregateSizes_ != Teuchos::null && !forceRecompute) {

      return aggregateSizes_;

    } else {

      //invalidate previous sizes.
      aggregateSizes_ = Teuchos::null;

      Teuchos::ArrayRCP<LO> aggregateSizes;
      aggregateSizes = Teuchos::ArrayRCP<LO>(nAggregates_,0);
      int myPid = vertex2AggId_->getMap()->getComm()->getRank();
      Teuchos::ArrayRCP<LO> procWinner   = procWinner_->getDataNonConst(0);
      Teuchos::ArrayRCP<LO> vertex2AggId = vertex2AggId_->getDataNonConst(0);
      LO size = procWinner.size();

      //for (LO i = 0; i < nAggregates_; ++i) aggregateSizes[i] = 0;
      for (LO k = 0; k < size; ++k ) {
        if (procWinner[k] == myPid) aggregateSizes[vertex2AggId[k]]++;
      }

      aggregateSizes_ = aggregateSizes;

      return aggregateSizes;
    }

  } //ComputeAggSizesNodes

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  std::string Aggregates<LocalOrdinal, GlobalOrdinal, Node>::description() const {
    std::ostringstream out;
    out << BaseClass::description();
    if (nGlobalAggregates_ == -1) out << "{nGlobalAggregates = not computed}";
    else                            out << "{nGlobalAggregates = " << nGlobalAggregates_ << "}";
    return out.str();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void Aggregates<LocalOrdinal, GlobalOrdinal, Node>::print(Teuchos::FancyOStream &out, const Teuchos::EVerbosityLevel verbLevel) const {
    MUELU_DESCRIBE;


    if (verbLevel & Statistics1) {
      if (nGlobalAggregates_ == -1) out0 << "Global number of aggregates: not computed " << std::endl;
      else                            out0 << "Global number of aggregates: " << nGlobalAggregates_ << std::endl;
    }

    if(verbLevel == Teuchos::VERB_EXTREME) {
      for(size_t j=0; j <vertex2AggId_->getNumVectors(); j++) {
        auto data = vertex2AggId_->getData(j);
        for(size_t i=0; i<vertex2AggId_->getLocalLength(); i++) {
          out<<i<<" : "<< data[i] <<std::endl;
        }
        out<<std::endl;
      }
    }
    
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  GlobalOrdinal Aggregates<LocalOrdinal, GlobalOrdinal, Node>::GetNumGlobalAggregatesComputeIfNeeded() {
    if (nGlobalAggregates_ != -1) {
      LO nAggregates = GetNumAggregates();
      GO nGlobalAggregates; 
      MueLu_sumAll(vertex2AggId_->getMap()->getComm(), (GO)nAggregates, nGlobalAggregates);
      SetNumGlobalAggregates(nGlobalAggregates); 
    }
    return nGlobalAggregates_;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  const RCP<const Xpetra::Map<LocalOrdinal,GlobalOrdinal, Node> > Aggregates<LocalOrdinal, GlobalOrdinal, Node>::GetMap() const {
    return vertex2AggId_->getMap();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void Aggregates<LocalOrdinal, GlobalOrdinal, Node>::ComputeNodesInAggregate(Array<LO> & aggPtr, Array<LO> & aggNodes, Array<LO> & unaggregated) const {
    LO numAggs  = GetNumAggregates();
    LO numNodes = vertex2AggId_->getLocalLength();
    Teuchos::ArrayRCP<const LO> vertex2AggId = vertex2AggId_->getData(0);
    Teuchos::ArrayRCP<LO> aggSizes = ComputeAggregateSizes(true);
    LO INVALID = Teuchos::OrdinalTraits<LO>::invalid();

    aggPtr.resize(numAggs+1);
    Array<LO> aggCurr(numAggs+1);
    aggNodes.resize(numNodes);
    unaggregated.resize(numNodes);

    LO currNumUnaggregated=0;

    // Construct the "rowptr" and the counter
    aggPtr[0] = 0; 
    for(LO i=0; i<numAggs; i++) {
      aggPtr[i+1] = aggSizes[i] + aggPtr[i];
      aggCurr[i] = aggPtr[i];
    }
                     
    // Stick the nodes in each aggregate's spot
    for(LO i=0; i<numNodes; i++) {
      LO aggregate = vertex2AggId[i];
      if(aggregate !=INVALID) {
        aggNodes[aggCurr[aggregate]] = i;
        aggCurr[aggregate]++;
      }
      else {
        unaggregated[currNumUnaggregated] = i;
        currNumUnaggregated++;
      }
    }
    unaggregated.resize(currNumUnaggregated);

  }


} //namespace MueLu

#endif // MUELU_AGGREGATES_DEF_HPP