MueLu_RepartitionInterface_def.hpp

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/*
 * MueLu_RepartitionInterface_def.hpp
 *
 *  Created on: 5 Sep 2013
 *      Author: wiesner
 */

#ifndef MUELU_REPARTITIONINTERFACE_DEF_HPP_
#define MUELU_REPARTITIONINTERFACE_DEF_HPP_

#include "MueLu_RepartitionInterface_decl.hpp"

#include "MueLu_Level.hpp"
#include "MueLu_Exceptions.hpp"
#include "MueLu_Monitor.hpp"
#include "MueLu_Graph.hpp"
#include "MueLu_AmalgamationFactory.hpp"
#include "MueLu_AmalgamationInfo.hpp"
#include "MueLu_Utilities.hpp"


namespace MueLu {

 template <class LocalOrdinal, class GlobalOrdinal, class Node>
 RCP<const ParameterList> RepartitionInterface<LocalOrdinal, GlobalOrdinal, Node>::GetValidParameterList() const {
    RCP<ParameterList> validParamList = rcp(new ParameterList());
    validParamList->set< RCP<const FactoryBase> >("A",                    Teuchos::null, "Factory of the matrix A");
    validParamList->set< RCP<const FactoryBase> >("number of partitions", Teuchos::null, "Instance of RepartitionHeuristicFactory.");
    validParamList->set< RCP<const FactoryBase> >("AmalgamatedPartition", Teuchos::null, "(advanced) Factory generating the AmalgamatedPartition (e.g. an IsorropiaInterface)");

    return validParamList;
  }


  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void RepartitionInterface<LocalOrdinal, GlobalOrdinal, Node>::DeclareInput(Level & currentLevel) const {
    Input(currentLevel, "A");
    Input(currentLevel, "number of partitions");
    Input(currentLevel, "AmalgamatedPartition");
  } //DeclareInput()

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void RepartitionInterface<LocalOrdinal, GlobalOrdinal, Node>::Build(Level &level) const {
    FactoryMonitor m(*this, "Build", level);

    RCP<Matrix>      A                                  = Get< RCP<Matrix> >     (level, "A");
    RCP<Xpetra::Vector<GO, LO, GO, NO> > amalgPartition = Get< RCP<Xpetra::Vector<GO, LO, GO, NO> > >(level, "AmalgamatedPartition");
    int numParts                                        = Get<int>(level, "number of partitions");

    RCP<const Map> rowMap        = A->getRowMap();

    // standard case: use matrix info and amalgamated rebalancing info to create "Partition" vector
    RCP<const Teuchos::Comm< int > > comm = A->getRowMap()->getComm();

    // Short cut: if we only need one partition, then create a dummy partition vector
    if (numParts == 1 || numParts == -1) {
      // Single processor, decomposition is trivial: all zeros
      RCP<Xpetra::Vector<GO,LO,GO,NO> > decomposition = Xpetra::VectorFactory<GO, LO, GO, NO>::Build(rowMap, true);
      Set(level, "Partition", decomposition);
      return;
    }/* else if (numParts == -1) {
      // No repartitioning
      RCP<Xpetra::Vector<GO,LO,GO,NO> > decomposition = Teuchos::null; //Xpetra::VectorFactory<GO, LO, GO, NO>::Build(rowMap, true);
      //decomposition->putScalar(Teuchos::as<Scalar>(comm->getRank()));
      Set(level, "Partition", decomposition);
      return;
    }*/

    ArrayRCP<GO> amalgPartitionData = amalgPartition->getDataNonConst(0);
    RCP<const Map> nodeMap       = amalgPartition->getMap();

    // extract amalgamation information from matrix A
    LO blockdim = 1;                          // block dim for fixed size blocks
    LO blockid          = -1;  // block id in strided map
    LO nStridedOffset   = 0;   // DOF offset for strided block id "blockid" (default = 0)
    LO stridedblocksize = blockdim; // size of strided block id "blockid" (default = fullblocksize, only if blockid!=-1 stridedblocksize <= fullblocksize)

    // 1) check for blocking/striding information
    //    fill above variables
    if(A->IsView("stridedMaps") &&
       Teuchos::rcp_dynamic_cast<const StridedMap>(A->getRowMap("stridedMaps")) != Teuchos::null) {
      Xpetra::viewLabel_t oldView = A->SwitchToView("stridedMaps"); // note: "stridedMaps are always non-overlapping (correspond to range and domain maps!)
      RCP<const StridedMap> strMap = Teuchos::rcp_dynamic_cast<const StridedMap>(A->getRowMap());
      TEUCHOS_TEST_FOR_EXCEPTION(strMap == Teuchos::null,Exceptions::BadCast,"MueLu::RepartitionInterface::Build: cast to strided row map failed.");
      blockdim = strMap->getFixedBlockSize();
      blockid  = strMap->getStridedBlockId();
      if (blockid > -1) {
        std::vector<size_t> stridingInfo = strMap->getStridingData();
        for (size_t j = 0; j < Teuchos::as<size_t>(blockid); j++)
          nStridedOffset += stridingInfo[j];
        stridedblocksize = Teuchos::as<LocalOrdinal>(stridingInfo[blockid]);

      } else {
        stridedblocksize = blockdim;
      }
      oldView = A->SwitchToView(oldView);
      //GetOStream(Statistics0, -1) << "RepartitionInterface::Build():" << " found blockdim=" << blockdim << " from strided maps (blockid=" << blockid << ", strided block size=" << stridedblocksize << "). offset=" << offset << std::endl;
    } else GetOStream(Statistics0, -1) << "RepartitionInterface::Build(): no striding information available. Use blockdim=1 with offset=0" << std::endl;

    // vector which stores final (unamalgamated) repartitioning
    RCP<Xpetra::Vector<GO, LO, GO, NO> > decomposition = Xpetra::VectorFactory<GO, LO, GO, NO>::Build(rowMap, false);
    ArrayRCP<GO> decompEntries = decomposition->getDataNonConst(0);

    TEUCHOS_TEST_FOR_EXCEPTION(Teuchos::as<int>(nodeMap->getNodeNumElements())*stridedblocksize != Teuchos::as<int>(rowMap->getNodeNumElements()), Exceptions::RuntimeError, "Inconsistency between nodeMap and dofMap: we are supporting block maps only. No support for general strided maps, yet!");

    //RCP<std::map<GO,std::vector<GO> > > nodegid2dofgids = amalgInfo->GetGlobalAmalgamationParams();

    // fill vector with information about partitioning
    // TODO: we assume simple block maps here
    // TODO: adapt this to usage of nodegid2dofgids
    for(size_t i = 0; i < nodeMap->getNodeNumElements(); i++) {
      // not fully sure about this. We're filling local ids in the decomposition vector with
      // the results stored in array. The decomposition vector is created using the rowMap of A

      // transform local node id to global node id.
      //GO gNodeId = nodeMap->getGlobalElement(i);

      // extract global DOF ids that belong to gNodeId
      /*std::vector<GlobalOrdinal> DOFs = (*nodegid2dofgids)[gNodeId];
      for(size_t j=0; j<stridedblocksize; j++) {
        decompEntries[i*stridedblocksize + j] = myRank;
      }*/
      for (LO j = 0; j < stridedblocksize/*DOFs.size()*/; j++) {
        // transform global DOF ids to local DOF ids using rowMap
        // note: The vector decomposition is based on rowMap
        //LO lDofId = rowMap->getLocalElement(DOFs[j]);     // -> i doubt that we need this!

        // put the same domain id to all DOFs of the same node
        decompEntries[i*stridedblocksize + j] = amalgPartitionData[i];
        //decompEntries[lDofId] = amalgPartitionData[i];
      }

    }

    Set(level, "Partition", decomposition);

  } //Build()



} //namespace MueLu


#endif /* MUELU_REPARTITIONINTERFACE_DEF_HPP_ */