Tpetra_Import.hpp

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// 
//          Tpetra: Templated Linear Algebra Services Package
//                 Copyright (2008) Sandia Corporation
// 
// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
// license for use of this work by or on behalf of the U.S. Government.
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// Lesser General Public License for more details.
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// You should have received a copy of the GNU Lesser General Public
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// Questions? Contact Michael A. Heroux (maherou@sandia.gov) 
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#ifndef TPETRA_IMPORT_HPP
#define TPETRA_IMPORT_HPP

#include <Kokkos_DefaultNode.hpp>
#include <Teuchos_Describable.hpp>
#include <Teuchos_as.hpp>
#include "Tpetra_Map.hpp"
#include "Tpetra_Util.hpp"
#include "Tpetra_ImportExportData.hpp"
#include "Tpetra_Distributor.hpp"
#include <iterator>

namespace Tpetra {


  template <class LocalOrdinal, class GlobalOrdinal = LocalOrdinal, class Node = Kokkos::DefaultNode::DefaultNodeType>
  class Import: public Teuchos::Describable {

  public:



    Import(const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & source, 
           const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & target);

    Import(const Import<LocalOrdinal,GlobalOrdinal,Node> & import);

    ~Import();




    size_t getNumSameIDs() const;

    size_t getNumPermuteIDs() const;

    Teuchos::ArrayView<const LocalOrdinal> getPermuteFromLIDs() const;

    Teuchos::ArrayView<const LocalOrdinal> getPermuteToLIDs() const;

    size_t getNumRemoteIDs() const;

    Teuchos::ArrayView<const LocalOrdinal> getRemoteLIDs() const;

    size_t getNumExportIDs() const;

    Teuchos::ArrayView<const LocalOrdinal> getExportLIDs() const;

    Teuchos::ArrayView<const int> getExportImageIDs() const;

    const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & getSourceMap() const;

    const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & getTargetMap() const;

    Distributor & getDistributor() const;

    Import<LocalOrdinal,GlobalOrdinal,Node>& operator = (const Import<LocalOrdinal,GlobalOrdinal,Node> & Source);




    virtual void print(std::ostream& os) const;


  private:

    Teuchos::RCP<ImportExportData<LocalOrdinal,GlobalOrdinal,Node> > ImportData_;
    Teuchos::RCP<Teuchos::Array<GlobalOrdinal> > remoteGIDs_;

    // subfunctions used by constructor
    //==============================================================================
    // sets up numSameIDs_, numPermuteIDs_, and numRemoteIDs_
    // these variables are already initialized to 0 by the ImportExportData ctr.
    // also sets up permuteToLIDs_, permuteFromLIDs_, and remoteLIDs_
    void setupSamePermuteRemote();
    void setupExport();
  };

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Import<LocalOrdinal,GlobalOrdinal,Node>::Import(const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & source, 
                                                  const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & target) {
    ImportData_ = Teuchos::rcp(new ImportExportData<LocalOrdinal,GlobalOrdinal,Node>(source, target));
    // call subfunctions
    setupSamePermuteRemote();
    if( source->isDistributed()) {
      setupExport();
    }
    // don't need remoteGIDs_ anymore
    remoteGIDs_ = Teuchos::null;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Import<LocalOrdinal,GlobalOrdinal,Node>::Import(const Import<LocalOrdinal,GlobalOrdinal,Node> & import)
  : ImportData_(import.ImportData_)
  {}

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Import<LocalOrdinal,GlobalOrdinal,Node>::~Import() 
  {}

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  size_t Import<LocalOrdinal,GlobalOrdinal,Node>::getNumSameIDs() const {
    return ImportData_->numSameIDs_;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  size_t Import<LocalOrdinal,GlobalOrdinal,Node>::getNumPermuteIDs() const {
    return ImportData_->permuteFromLIDs_.size();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Teuchos::ArrayView<const LocalOrdinal> 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getPermuteFromLIDs() const {
    return ImportData_->permuteFromLIDs_();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Teuchos::ArrayView<const LocalOrdinal>
  Import<LocalOrdinal,GlobalOrdinal,Node>::getPermuteToLIDs() const {
    return ImportData_->permuteToLIDs_();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  size_t Import<LocalOrdinal,GlobalOrdinal,Node>::getNumRemoteIDs() const {
    return ImportData_->remoteLIDs_.size();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Teuchos::ArrayView<const LocalOrdinal> 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getRemoteLIDs() const {
    return ImportData_->remoteLIDs_();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  size_t Import<LocalOrdinal,GlobalOrdinal,Node>::getNumExportIDs() const {
    return ImportData_->exportLIDs_.size();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Teuchos::ArrayView<const LocalOrdinal> 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getExportLIDs() const {
    return ImportData_->exportLIDs_();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Teuchos::ArrayView<const int> 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getExportImageIDs() const {
    return ImportData_->exportImageIDs_();
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getSourceMap() const {
    return ImportData_->source_;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  const Teuchos::RCP<const Map<LocalOrdinal,GlobalOrdinal,Node> > & 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getTargetMap() const {
    return ImportData_->target_;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Distributor & 
  Import<LocalOrdinal,GlobalOrdinal,Node>::getDistributor() const {
    return ImportData_->distributor_;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  Import<LocalOrdinal,GlobalOrdinal,Node>& 
  Import<LocalOrdinal,GlobalOrdinal,Node>::operator=(const Import<LocalOrdinal,GlobalOrdinal,Node> & Source) {
    ImportData_ = Source.ImportData_;
    return *this;
  }

  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void Import<LocalOrdinal,GlobalOrdinal,Node>::print(std::ostream& os) const {
    using std::endl;
    Teuchos::ArrayView<const LocalOrdinal> av;
    Teuchos::ArrayView<const int> avi;
    const Teuchos::RCP<const Teuchos::Comm<int> > & comm = getSourceMap()->getComm();
    int myImageID = comm->getRank();
    int numImages = comm->getSize();
    for (int imageCtr = 0; imageCtr < numImages; ++imageCtr) {
      if(myImageID == imageCtr) {
        os << endl;
        if(myImageID == 0) { // this is the root node (only output this info once)
          os << "Import Data Members:" << endl;
        }
        os << "Image ID       : " << myImageID << endl;
        os << "permuteFromLIDs: {"; av = getPermuteFromLIDs(); std::copy(av.begin(),av.end(),std::ostream_iterator<LocalOrdinal>(os," ")); os << " }" << endl;
        os << "permuteToLIDs  : {"; av = getPermuteToLIDs();   std::copy(av.begin(),av.end(),std::ostream_iterator<LocalOrdinal>(os," ")); os << " }" << endl;
        os << "remoteLIDs     : {"; av = getRemoteLIDs();      std::copy(av.begin(),av.end(),std::ostream_iterator<LocalOrdinal>(os," ")); os << " }" << endl;
        os << "exportLIDs     : {"; av = getExportLIDs();      std::copy(av.begin(),av.end(),std::ostream_iterator<LocalOrdinal>(os," ")); os << " }" << endl;
        os << "exportImageIDs : {"; avi = getExportImageIDs();  std::copy(avi.begin(),avi.end(),std::ostream_iterator<int>(os," ")); os << " }" << endl;
        os << "numSameIDs     : " << getNumSameIDs() << endl;
        os << "numPermuteIDs  : " << getNumPermuteIDs() << endl;
        os << "numRemoteIDs   : " << getNumRemoteIDs() << endl;
        os << "numExportIDs   : " << getNumExportIDs() << endl;
      }
      // Do a few global ops to give I/O a chance to complete
      comm->barrier();
      comm->barrier();
      comm->barrier();
    }
    if (myImageID == 0) {
      os << "\nSource Map: " << endl; 
    }
    os << *getSourceMap();
    if (myImageID == 0) {
      os << "\nTarget Map: " << endl; 
    }
    os << *getTargetMap();
  }


  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void Import<LocalOrdinal,GlobalOrdinal,Node>::setupSamePermuteRemote() {
    const Map<LocalOrdinal,GlobalOrdinal,Node> & source = *getSourceMap();
    const Map<LocalOrdinal,GlobalOrdinal,Node> & target = *getTargetMap();
    Teuchos::ArrayView<const GlobalOrdinal> sourceGIDs = source.getNodeElementList();
    Teuchos::ArrayView<const GlobalOrdinal> targetGIDs = target.getNodeElementList();

    // -- compute numSameIDs_ ---
    // go through GID lists of source and target. if the ith GID on both is the same, 
    // increment numSameIDs_ and try the next. as soon as you come to a pair that don't
    // match, give up.
    typename Teuchos::ArrayView<const GlobalOrdinal>::iterator sourceIter = sourceGIDs.begin(),
                                                         targetIter = targetGIDs.begin();
    while( sourceIter != sourceGIDs.end() && targetIter != targetGIDs.end() && *sourceIter == *targetIter )
    {
      ++ImportData_->numSameIDs_;
      ++sourceIter;
      ++targetIter;
    }
    // targetIter should now point to the GID of the first non-same entry or the end of targetGIDs

    // -- compute numPermuteIDs and numRemoteIDs --
    // -- fill permuteToLIDs_, permuteFromLIDs_, remoteGIDs_, and remoteLIDs_ --
    // go through remaining entries in targetGIDs. if source owns that GID, 
    // increment numPermuteIDs_, and add entries to permuteToLIDs_ and permuteFromLIDs_.
    // otherwise increment numRemoteIDs_ and add entries to remoteLIDs_ and remoteGIDs_.
    remoteGIDs_ = Teuchos::rcp( new Teuchos::Array<GlobalOrdinal>() );
    for (; targetIter != targetGIDs.end(); ++targetIter) {
      if (source.isNodeGlobalElement(*targetIter)) {
        // both source and target list this GID (*targetIter)
        // determine the LIDs for this GID on both Maps and add them to the permutation lists
        ImportData_->permuteToLIDs_.push_back(target.getLocalElement(*targetIter));
        ImportData_->permuteFromLIDs_.push_back(source.getLocalElement(*targetIter));
      }
      else {
        // this GID is on another processor; store it, along with its destination LID on this processor
        remoteGIDs_->push_back(*targetIter);
        ImportData_->remoteLIDs_.push_back(target.getLocalElement(*targetIter));
      }
    }

    TEST_FOR_EXCEPTION( (getNumRemoteIDs() > 0) && !source.isDistributed(), std::runtime_error, 
        Teuchos::typeName(*this) << "::setupSamePermuteRemote(): Target has remote LIDs but Source is not distributed globally.");
  }


  template <class LocalOrdinal, class GlobalOrdinal, class Node>
  void Import<LocalOrdinal,GlobalOrdinal,Node>::setupExport() {
    const Map<LocalOrdinal,GlobalOrdinal,Node> & source = *getSourceMap();

    // create remoteImageID list: for each entry remoteGIDs[i],
    // remoteImageIDs[i] will contain the ImageID of the image that owns that GID.
    // check for GIDs that exist in target but not in source: we see this if getRemoteIndexList returns true
    Teuchos::ArrayView<GlobalOrdinal> remoteGIDs = (*remoteGIDs_)();
    Teuchos::Array<int> remoteImageIDs(remoteGIDs.size());
    TEST_FOR_EXCEPTION( source.getRemoteIndexList(remoteGIDs, remoteImageIDs()) == IDNotPresent, std::runtime_error,
        "Tpetra::Import::setupExport(): Target has GIDs not found in Source.");

    // sort remoteImageIDs in ascending order
    // apply same permutation to remoteGIDs_
    sort2(remoteImageIDs.begin(), remoteImageIDs.end(), remoteGIDs.begin());

    // call Distributor.createFromRecvs()
    // takes in remoteGIDs and remoteImageIDs_
    // returns exportLIDs_, exportImageIDs_ 
    Teuchos::ArrayRCP<GlobalOrdinal> exportGIDs;
    ImportData_->distributor_.createFromRecvs(remoteGIDs().getConst(), remoteImageIDs, exportGIDs, ImportData_->exportImageIDs_);
    // -- exportGIDs and exportImageIDs_ allocated by createFromRecvs (the former contains GIDs, we will convert to LIDs below) --

    // convert exportGIDs from GIDs to LIDs
    if (exportGIDs != Teuchos::null) {
      ImportData_->exportLIDs_ = Teuchos::arcp<LocalOrdinal>(exportGIDs.size());
    }
    typename Teuchos::ArrayRCP<LocalOrdinal>::iterator dst = ImportData_->exportLIDs_.begin();
    typename Teuchos::ArrayRCP<GlobalOrdinal>::const_iterator src = exportGIDs.begin();
    while (src != exportGIDs.end())
    {
      (*dst++) = source.getLocalElement(*src++);
    }
  }

} // namespace Tpetra

#endif // TPETRA_IMPORT_HPP