MueLu_UzawaSmoother_def.hpp

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/*
 * MueLu_UzawaSmoother_def.hpp
 *
 *  Created on: 13 May 2014
 *      Author: wiesner
 */

#ifndef MUELU_UZAWASMOOTHER_DEF_HPP_
#define MUELU_UZAWASMOOTHER_DEF_HPP_

#include "Teuchos_ArrayViewDecl.hpp"
#include "Teuchos_ScalarTraits.hpp"

#include "MueLu_ConfigDefs.hpp"

#include <Xpetra_Matrix.hpp>
#include <Xpetra_BlockedCrsMatrix.hpp>
#include <Xpetra_MultiVectorFactory.hpp>
#include <Xpetra_VectorFactory.hpp>

#include "MueLu_UzawaSmoother_decl.hpp"
#include "MueLu_Level.hpp"
#include "MueLu_Utilities.hpp"
#include "MueLu_Monitor.hpp"
#include "MueLu_HierarchyUtils.hpp"
#include "MueLu_SmootherBase.hpp"
#include "MueLu_SubBlockAFactory.hpp"

// include files for default FactoryManager
#include "MueLu_SchurComplementFactory.hpp"
#include "MueLu_DirectSolver.hpp"
#include "MueLu_SmootherFactory.hpp"
#include "MueLu_FactoryManager.hpp"

namespace MueLu {

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::UzawaSmoother()
    : type_("Uzawa"), A_(Teuchos::null)
  {
  }

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

  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
  RCP<const ParameterList> UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::GetValidParameterList() const {
    RCP<ParameterList> validParamList = rcp(new ParameterList());

    validParamList->set< RCP<const FactoryBase> >("A",                  Teuchos::null, "Generating factory of the matrix A");
    validParamList->set< Scalar >                ("Damping factor",     1.0, "Damping/Scaling factor in SIMPLE");
    validParamList->set< LocalOrdinal >          ("Sweeps",             1, "Number of SIMPLE sweeps (default = 1)");

    return validParamList;
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::AddFactoryManager(RCP<const FactoryManagerBase> FactManager, int pos) {
    TEUCHOS_TEST_FOR_EXCEPTION(pos < 0, Exceptions::RuntimeError, "MueLu::UzawaSmoother::AddFactoryManager: parameter \'pos\' must not be negative! error.");

    size_t myPos = Teuchos::as<size_t>(pos);

    if (myPos < FactManager_.size()) {
      // replace existing entris in FactManager_ vector
      FactManager_.at(myPos) = FactManager;
    } else if( myPos == FactManager_.size()) {
      // add new Factory manager in the end of the vector
      FactManager_.push_back(FactManager);
    } else { // if(myPos > FactManager_.size())
      RCP<Teuchos::FancyOStream> out = Teuchos::fancyOStream(Teuchos::rcpFromRef(std::cout));
      *out << "Warning: cannot add new FactoryManager at proper position " << pos << ". The FactoryManager is just appended to the end. Check this!" << std::endl;

      // add new Factory manager in the end of the vector
      FactManager_.push_back(FactManager);
    }

  }


  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::SetVelocityPredictionFactoryManager(RCP<FactoryManager> FactManager) {
    AddFactoryManager(FactManager, 0); // overwrite factory manager for predicting the primary variable
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::SetSchurCompFactoryManager(RCP<FactoryManager> FactManager) {
    AddFactoryManager(FactManager, 1); // overwrite factory manager for SchurComplement
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::DeclareInput(Level &currentLevel) const {
    currentLevel.DeclareInput("A",this->GetFactory("A").get());

    TEUCHOS_TEST_FOR_EXCEPTION(FactManager_.size() != 2, Exceptions::RuntimeError,"MueLu::UzawaSmoother::DeclareInput: You have to declare two FactoryManagers with a \"Smoother\" object: One for predicting the primary variable and one for the SchurComplement system. The smoother for the SchurComplement system needs a SchurComplementFactory as input for variable \"A\". make sure that you use the same proper damping factors for omega both in the SchurComplementFactory and in the SIMPLE smoother!");

    // loop over all factory managers for the subblocks of blocked operator A
    std::vector<Teuchos::RCP<const FactoryManagerBase> >::const_iterator it;
    for(it = FactManager_.begin(); it!=FactManager_.end(); ++it) {
      SetFactoryManager currentSFM  (rcpFromRef(currentLevel),   *it);

      // request "Smoother" for current subblock row.
      currentLevel.DeclareInput("PreSmoother",(*it)->GetFactory("Smoother").get());
    }
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Setup(Level &currentLevel) {

    FactoryMonitor m(*this, "Setup blocked Uzawa Smoother", currentLevel);

    if (SmootherPrototype::IsSetup() == true)
      this->GetOStream(Warnings0) << "MueLu::UzawaSmoother::Setup(): Setup() has already been called";

    // extract blocked operator A from current level
    A_ = Factory::Get<RCP<Matrix> > (currentLevel, "A");

    RCP<BlockedCrsMatrix> bA = Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(A_);
    TEUCHOS_TEST_FOR_EXCEPTION(bA == Teuchos::null, Exceptions::BadCast, "MueLu::UzawaSmoother::Setup: input matrix A is not of type BlockedCrsMatrix! error.");

    // store map extractors
    rangeMapExtractor_ = bA->getRangeMapExtractor();
    domainMapExtractor_ = bA->getDomainMapExtractor();

    // Store the blocks in local member variables
    F_ = bA->getMatrix(0, 0);
    G_ = bA->getMatrix(0, 1);
    D_ = bA->getMatrix(1, 0);
    Z_ = bA->getMatrix(1, 1);

    // Set the Smoother
    // carefully switch to the SubFactoryManagers (defined by the users)
    {
      RCP<const FactoryManagerBase> velpredictFactManager = FactManager_.at(0);
      SetFactoryManager currentSFM  (rcpFromRef(currentLevel), velpredictFactManager);
      velPredictSmoo_ = currentLevel.Get< RCP<SmootherBase> >("PreSmoother",velpredictFactManager->GetFactory("Smoother").get());
    }
    {
      RCP<const FactoryManagerBase> schurFactManager = FactManager_.at(1);
      SetFactoryManager currentSFM  (rcpFromRef(currentLevel), schurFactManager);
      schurCompSmoo_ = currentLevel.Get< RCP<SmootherBase> >("PreSmoother", schurFactManager->GetFactory("Smoother").get());
    }

    SmootherPrototype::IsSetup(true);
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Apply(MultiVector& X, const MultiVector& B, bool InitialGuessIsZero) const
  {
    TEUCHOS_TEST_FOR_EXCEPTION(SmootherPrototype::IsSetup() == false, Exceptions::RuntimeError, "MueLu::UzawaSmoother::Apply(): Setup() has not been called");

    Teuchos::RCP<Teuchos::FancyOStream> fos = Teuchos::getFancyOStream(Teuchos::rcpFromRef(std::cout));

    SC zero = Teuchos::ScalarTraits<SC>::zero(), one = Teuchos::ScalarTraits<SC>::one();

    // The following boolean flags catch the case where we need special transformation
    // for the GIDs when calling the subsmoothers.
    RCP<BlockedCrsMatrix> bA00 = Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(F_);
    RCP<BlockedCrsMatrix> bA11 = Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(Z_);
    bool bFThyraSpecialTreatment = false;
    bool bZThyraSpecialTreatment = false;
    if (bA00 != Teuchos::null) {
      if(bA00->Rows() == 1 && bA00->Cols() == 1 && rangeMapExtractor_->getThyraMode() == true) bFThyraSpecialTreatment = true;
    }
    if (bA11 != Teuchos::null) {
      if(bA11->Rows() == 1 && bA11->Cols() == 1 && rangeMapExtractor_->getThyraMode() == true) bZThyraSpecialTreatment = true;
    }

    // extract parameters from internal parameter list
    const ParameterList & pL = Factory::GetParameterList();
    LocalOrdinal nSweeps = pL.get<LocalOrdinal>("Sweeps");
    Scalar omega = pL.get<Scalar>("Damping factor");

    // wrap current solution vector in RCP
    RCP<MultiVector> rcpX = Teuchos::rcpFromRef(X);

    // create residual vector
    // contains current residual of current solution X with rhs B
    RCP<MultiVector> residual = MultiVectorFactory::Build(B.getMap(), B.getNumVectors());

    // incrementally improve solution vector X
    for (LocalOrdinal run = 0; run < nSweeps; ++run) {
      // 1) calculate current residual
      residual->update(one,B,zero); // residual = B
      A_->apply(*rcpX, *residual, Teuchos::NO_TRANS, -one, one);

      // split residual vector
      Teuchos::RCP<MultiVector> r1 = rangeMapExtractor_->ExtractVector(residual, 0);
      Teuchos::RCP<MultiVector> r2 = rangeMapExtractor_->ExtractVector(residual, 1);

      // 2) solve F * \Delta \tilde{x}_1 = r_1
      //    start with zero guess \Delta \tilde{x}_1
      RCP<MultiVector> xtilde1 = MultiVectorFactory::Build(F_->getRowMap(),X.getNumVectors(),true);

      // Special handling if SchurComplement operator was a 1x1 blocked operator in Thyra mode
      // Then, we have to translate the Xpetra offset GIDs to plain Thyra GIDs and vice versa
      if(bFThyraSpecialTreatment == true) {
        RCP<MultiVector> xtilde1_thyra = domainMapExtractor_->getVector(0, X.getNumVectors(), true);
        RCP<MultiVector> r1_thyra = rangeMapExtractor_->getVector(0, B.getNumVectors(), true);
        // transform vector
        for(size_t k=0; k < r1->getNumVectors(); k++) {
          Teuchos::ArrayRCP<const Scalar> xpetraVecData  = r1->getData(k);
          Teuchos::ArrayRCP<Scalar> thyraVecData = r1_thyra->getDataNonConst(k);
          for(size_t i=0; i < r1->getLocalLength(); i++) {
            thyraVecData[i] = xpetraVecData[i];
          }
        }

        velPredictSmoo_->Apply(*xtilde1_thyra,*r1_thyra);

        for(size_t k=0; k < xtilde1_thyra->getNumVectors(); k++) {
          Teuchos::ArrayRCP<Scalar> xpetraVecData  = xtilde1->getDataNonConst(k);
          Teuchos::ArrayRCP<const Scalar> thyraVecData = xtilde1_thyra->getData(k);
          for(size_t i=0; i < xtilde1_thyra->getLocalLength(); i++) {
            xpetraVecData[i] = thyraVecData[i];
          }
        }
      } else {
        velPredictSmoo_->Apply(*xtilde1,*r1);
      }

      // 3) calculate rhs for SchurComp equation
      //    r_2 - D \Delta \tilde{x}_1
      RCP<MultiVector> schurCompRHS = MultiVectorFactory::Build(Z_->getRowMap(),B.getNumVectors());
      D_->apply(*xtilde1,*schurCompRHS);
      schurCompRHS->update(one,*r2,-one);

      // 4) solve SchurComp equation
      //    start with zero guess \Delta \tilde{x}_2
      RCP<MultiVector> xtilde2 = MultiVectorFactory::Build(Z_->getRowMap(),X.getNumVectors(),true);

      // Special handling if SchurComplement operator was a 1x1 blocked operator in Thyra mode
      // Then, we have to translate the Xpetra offset GIDs to plain Thyra GIDs and vice versa
      if(bZThyraSpecialTreatment == true) {
        RCP<MultiVector> xtilde2_thyra = domainMapExtractor_->getVector(1, X.getNumVectors(), true);
        RCP<MultiVector> schurCompRHS_thyra = rangeMapExtractor_->getVector(1, B.getNumVectors(), true);
        // transform vector
        for(size_t k=0; k < schurCompRHS->getNumVectors(); k++) {
          Teuchos::ArrayRCP<const Scalar> xpetraVecData  = schurCompRHS->getData(k);
          Teuchos::ArrayRCP<Scalar> thyraVecData = schurCompRHS_thyra->getDataNonConst(k);
          for(size_t i=0; i < schurCompRHS->getLocalLength(); i++) {
            thyraVecData[i] = xpetraVecData[i];
          }
        }

        schurCompSmoo_->Apply(*xtilde2_thyra,*schurCompRHS_thyra);

        for(size_t k=0; k < xtilde2_thyra->getNumVectors(); k++) {
          Teuchos::ArrayRCP<Scalar> xpetraVecData  = xtilde2->getDataNonConst(k);
          Teuchos::ArrayRCP<const Scalar> thyraVecData = xtilde2_thyra->getData(k);
          for(size_t i=0; i < xtilde2_thyra->getLocalLength(); i++) {
            xpetraVecData[i] = thyraVecData[i];
          }
        }
      } else {
        schurCompSmoo_->Apply(*xtilde2,*schurCompRHS);
      }

      // 5) extract parts of solution vector X
      Teuchos::RCP<MultiVector> x1 = domainMapExtractor_->ExtractVector(rcpX, 0);
      Teuchos::RCP<MultiVector> x2 = domainMapExtractor_->ExtractVector(rcpX, 1);

      // 6) update solution vector with increments xhat1 and xhat2
      //    rescale increment for x2 with omega_
      x1->update(omega,*xtilde1,one); // x1 = x1_old + omega xtilde1
      x2->update(omega,*xtilde2,one); // x2 = x2_old + omega xtilde2

      // write back solution in global vector X
      domainMapExtractor_->InsertVector(x1, 0, rcpX);
      domainMapExtractor_->InsertVector(x2, 1, rcpX);
    }
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  RCP<MueLu::SmootherPrototype<Scalar, LocalOrdinal, GlobalOrdinal, Node> >
  UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Copy() const {
    return rcp( new UzawaSmoother(*this) );
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  std::string UzawaSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::description() const {
    std::ostringstream out;
    out << SmootherPrototype::description();
    out << "{type = " << type_ << "}";
    return out.str();
  }

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

    if (verbLevel & Parameters0) {
      out0 << "Prec. type: " << type_ << /*" Sweeps: " << nSweeps_ << " damping: " << omega_ <<*/ std::endl;
    }

    if (verbLevel & Debug) {
      out0 << "IsSetup: " << Teuchos::toString(SmootherPrototype::IsSetup()) << std::endl;
    }
  }

} // namespace MueLu


#endif /* MUELU_UZAWASMOOTHER_DEF_HPP_ */