MueLu_SimpleSmoother_def.hpp

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#ifndef MUELU_SIMPLESMOOTHER_DEF_HPP_
#define MUELU_SIMPLESMOOTHER_DEF_HPP_
 
#include "Teuchos_ArrayViewDecl.hpp"
#include "Teuchos_ScalarTraits.hpp"
 
#include "MueLu_ConfigDefs.hpp"
 
#include <Xpetra_Matrix.hpp>
#include <Xpetra_CrsMatrixWrap.hpp>
#include <Xpetra_BlockedCrsMatrix.hpp>
#include <Xpetra_MultiVectorFactory.hpp>
#include <Xpetra_VectorFactory.hpp>
#include <Xpetra_ReorderedBlockedCrsMatrix.hpp>
 
#include "MueLu_SimpleSmoother_decl.hpp"
#include "MueLu_Level.hpp"
#include "MueLu_Utilities.hpp"
#include "MueLu_Monitor.hpp"
#include "MueLu_HierarchyUtils.hpp"
#include "MueLu_SmootherBase.hpp"
 
// include files for default FactoryManager
#include "MueLu_SchurComplementFactory.hpp"
#include "MueLu_FactoryManager.hpp"
 
namespace MueLu {
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::SimpleSmoother()
    : type_("SIMPLE"), A_(Teuchos::null) {}
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::~SimpleSmoother() {}
 
  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
  RCP<const ParameterList> SimpleSmoother<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)");
    validParamList->set<bool>("UseSIMPLEC", false, "Use SIMPLEC instead of SIMPLE (default = false)");
 
    return validParamList;
  }

  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::AddFactoryManager(RCP<const FactoryManagerBase> FactManager, int pos) {
    TEUCHOS_TEST_FOR_EXCEPTION(pos < 0, Exceptions::RuntimeError, "MueLu::SimpleSmoother::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 SimpleSmoother<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 SimpleSmoother<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 SimpleSmoother<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::SimpleSmoother::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 SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Setup(Level &currentLevel) {
 
    FactoryMonitor m(*this, "Setup blocked SIMPLE Smoother", currentLevel);
 
    if (SmootherPrototype::IsSetup() == true)
      this->GetOStream(Warnings0) << "MueLu::SimpleSmoother::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::SimpleSmoother::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);
 
    const ParameterList & pL = Factory::GetParameterList();
    bool bSIMPLEC = pL.get<bool>("UseSIMPLEC");
 
    // Create the inverse of the diagonal of F
    // TODO add safety check for zeros on diagonal of F!
    RCP<Vector> diagFVector = VectorFactory::Build(F_->getRowMap());
    if(!bSIMPLEC) {
      F_->getLocalDiagCopy(*diagFVector);       // extract diagonal of F
    } else {
      /*const RCP<const Map> rowmap = F_->getRowMap();
      size_t locSize = rowmap->getLocalNumElements();
      Teuchos::ArrayRCP<SC> diag = diagFVector->getDataNonConst(0);
      Teuchos::ArrayView<const LO> cols;
      Teuchos::ArrayView<const SC> vals;
      for (size_t i=0; i<locSize; ++i) { // loop over rows
        F_->getLocalRowView(i,cols,vals);
        Scalar absRowSum = Teuchos::ScalarTraits<Scalar>::zero();
        for (LO j=0; j<cols.size(); ++j) { // loop over cols
          absRowSum += Teuchos::ScalarTraits<Scalar>::magnitude(vals[j]);
        }
        diag[i] = absRowSum;
      }*/
      // TODO this does not work if F_ is nested!
      diagFVector = Utilities::GetLumpedMatrixDiagonal(*F_);
    }
    diagFinv_ = Utilities::GetInverse(diagFVector);
 
    // check whether diagFinv_ is a blocked vector with only 1 block
    RCP<BlockedVector> bdiagFinv = Teuchos::rcp_dynamic_cast<BlockedVector>(diagFinv_);
    if(bdiagFinv.is_null() == false && bdiagFinv->getBlockedMap()->getNumMaps() == 1) {
      RCP<Vector> nestedVec = bdiagFinv->getMultiVector(0,bdiagFinv->getBlockedMap()->getThyraMode())->getVectorNonConst(0);
      diagFinv_.swap(nestedVec);
    }
 
    // 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 SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Apply(MultiVector& X, const MultiVector& B, bool InitialGuessIsZero) const
  {
    TEUCHOS_TEST_FOR_EXCEPTION(SmootherPrototype::IsSetup() == false, Exceptions::RuntimeError,
        "MueLu::SimpleSmoother::Apply(): Setup() has not been called");
#if 0
    // TODO simplify this debug check
    RCP<MultiVector> rcpDebugX = Teuchos::rcpFromRef(X);
    RCP<const MultiVector> rcpDebugB = Teuchos::rcpFromRef(B);
    RCP<BlockedMultiVector> rcpBDebugX = Teuchos::rcp_dynamic_cast<BlockedMultiVector>(rcpDebugX);
    RCP<const BlockedMultiVector> rcpBDebugB = Teuchos::rcp_dynamic_cast<const BlockedMultiVector>(rcpDebugB);
    if(rcpBDebugB.is_null() == false) {
      //TEUCHOS_TEST_FOR_EXCEPTION(A_->getRangeMap()->isSameAs(*(B.getMap())) == false, Exceptions::RuntimeError, "MueLu::SimpleSmoother::Apply(): The map of RHS vector B is not the same as range map of the blocked operator A. Please check the map of B and A.");
    } else {
      //TEUCHOS_TEST_FOR_EXCEPTION(bA->getFullRangeMap()->isSameAs(*(B.getMap())) == false, Exceptions::RuntimeError, "MueLu::SimpleSmoother::Apply(): The map of RHS vector B is not the same as range map of the blocked operator A. Please check the map of B and A.");
    }
    if(rcpBDebugX.is_null() == false) {
      //TEUCHOS_TEST_FOR_EXCEPTION(A_->getDomainMap()->isSameAs(*(X.getMap())) == false, Exceptions::RuntimeError, "MueLu::SimpleSmoother::Apply(): The map of the solution vector X is not the same as domain map of the blocked operator A. Please check the map of X and A.");
    } else {
      //TEUCHOS_TEST_FOR_EXCEPTION(bA->getFullDomainMap()->isSameAs(*(X.getMap())) == false, Exceptions::RuntimeError, "MueLu::SimpleSmoother::Apply(): The map of the solution vector X is not the same as domain map of the blocked operator A. Please check the map of X and A.");
    }
#endif
 
    const SC zero = Teuchos::ScalarTraits<SC>::zero();
    const SC one = Teuchos::ScalarTraits<SC>::one();
 
    // extract parameters from internal parameter list
    const ParameterList & pL = Factory::GetParameterList();
    LocalOrdinal nSweeps = pL.get<LocalOrdinal>("Sweeps");
    Scalar omega = pL.get<Scalar>("Damping factor");
 
    // The boolean flags check whether we use Thyra or Xpetra style GIDs
    bool bRangeThyraMode = rangeMapExtractor_->getThyraMode(); //  && (Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(F_) == Teuchos::null);
    bool bDomainThyraMode = domainMapExtractor_->getThyraMode(); // && (Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(F_) == Teuchos::null);
 
    //RCP<Teuchos::FancyOStream> fancy = Teuchos::fancyOStream(Teuchos::rcpFromRef(std::cout));
 
    // wrap current solution vector in RCP
    RCP<MultiVector> rcpX = Teuchos::rcpFromRef(X);
    RCP<const MultiVector> rcpB = Teuchos::rcpFromRef(B);
 
    // make sure that both rcpX and rcpB are BlockedMultiVector objects
    bool bCopyResultX = false;
    bool bReorderX = false;
    bool bReorderB = false;
    RCP<BlockedCrsMatrix> bA = Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(A_);
    MUELU_TEST_FOR_EXCEPTION(bA.is_null() == true, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::Apply(): A_ must be a BlockedCrsMatrix");
    RCP<BlockedMultiVector> bX = Teuchos::rcp_dynamic_cast<BlockedMultiVector>(rcpX);
    RCP<const BlockedMultiVector> bB = Teuchos::rcp_dynamic_cast<const BlockedMultiVector>(rcpB);
 
    // check the type of operator
    RCP<Xpetra::ReorderedBlockedCrsMatrix<Scalar,LocalOrdinal,GlobalOrdinal,Node> > rbA =
            Teuchos::rcp_dynamic_cast<Xpetra::ReorderedBlockedCrsMatrix<Scalar,LocalOrdinal,GlobalOrdinal,Node> >(bA);
 
    if(rbA.is_null() == false) {
      // A is a ReorderedBlockedCrsMatrix and thus uses nested maps, retrieve BlockedCrsMatrix and use plain blocked
      // map for the construction of the blocked multivectors
 
      // check type of X vector
      if (bX.is_null() == true) {
        RCP<MultiVector> vectorWithBlockedMap = Teuchos::rcp(new BlockedMultiVector(rbA->getBlockedCrsMatrix()->getBlockedDomainMap(), rcpX));
        rcpX.swap(vectorWithBlockedMap);
        bCopyResultX = true;
        bReorderX = true;
      }
 
      // check type of B vector
      if (bB.is_null() == true) {
        RCP<const MultiVector> vectorWithBlockedMap = Teuchos::rcp(new BlockedMultiVector(rbA->getBlockedCrsMatrix()->getBlockedRangeMap(), rcpB));
        rcpB.swap(vectorWithBlockedMap);
        bReorderB = true;
      }
    }
    else {
      // A is a BlockedCrsMatrix and uses a plain blocked map
      if (bX.is_null() == true) {
        RCP<MultiVector> vectorWithBlockedMap = Teuchos::rcp(new BlockedMultiVector(bA->getBlockedDomainMap(), rcpX));
        rcpX.swap(vectorWithBlockedMap);
        bCopyResultX = true;
      }
 
      if(bB.is_null() == true) {
        RCP<const MultiVector> vectorWithBlockedMap = Teuchos::rcp(new BlockedMultiVector(bA->getBlockedRangeMap(),rcpB));
        rcpB.swap(vectorWithBlockedMap);
      }
    }
 
    // we now can guarantee that X and B are blocked multi vectors
    bX = Teuchos::rcp_dynamic_cast<BlockedMultiVector>(rcpX);
    bB = Teuchos::rcp_dynamic_cast<const BlockedMultiVector>(rcpB);
 
    // Finally we can do a reordering of the blocked multivectors if A is a ReorderedBlockedCrsMatrix
    if(rbA.is_null() == false) {
 
      Teuchos::RCP<const Xpetra::BlockReorderManager > brm = rbA->getBlockReorderManager();
 
      // check type of X vector
      if(bX->getBlockedMap()->getNumMaps() != bA->getDomainMapExtractor()->NumMaps() || bReorderX) {
        // X is a blocked multi vector but incompatible to the reordered blocked operator A
        Teuchos::RCP<MultiVector> reorderedBlockedVector = buildReorderedBlockedMultiVector(brm, bX);
        rcpX.swap(reorderedBlockedVector);
      }
 
      if(bB->getBlockedMap()->getNumMaps() != bA->getRangeMapExtractor()->NumMaps() || bReorderB) {
        // B is a blocked multi vector but incompatible to the reordered blocked operator A
        Teuchos::RCP<const MultiVector> reorderedBlockedVector = buildReorderedBlockedMultiVector(brm, bB);
        rcpB.swap(reorderedBlockedVector);
      }
    }
 
    // Throughout the rest of the algorithm rcpX and rcpB are used for solution vector and RHS
 
    // create residual vector
    // contains current residual of current solution X with rhs B
    RCP<MultiVector> residual = MultiVectorFactory::Build(rcpB->getMap(), rcpB->getNumVectors());
    RCP<BlockedMultiVector> bresidual = Teuchos::rcp_dynamic_cast<BlockedMultiVector>(residual);
    RCP<MultiVector> r1 = bresidual->getMultiVector(0,bRangeThyraMode);
    RCP<MultiVector> r2 = bresidual->getMultiVector(1,bRangeThyraMode);
 
    // helper vector 1
    RCP<MultiVector> xtilde = MultiVectorFactory::Build(rcpX->getMap(), rcpX->getNumVectors());
    RCP<BlockedMultiVector> bxtilde = Teuchos::rcp_dynamic_cast<BlockedMultiVector>(xtilde);
    RCP<MultiVector> xtilde1 = bxtilde->getMultiVector(0, bDomainThyraMode);
    RCP<MultiVector> xtilde2 = bxtilde->getMultiVector(1, bDomainThyraMode);
 
    // helper vector 2
    RCP<MultiVector> xhat = MultiVectorFactory::Build(rcpX->getMap(), rcpX->getNumVectors());
    RCP<BlockedMultiVector> bxhat = Teuchos::rcp_dynamic_cast<BlockedMultiVector>(xhat);
    RCP<MultiVector> xhat1 = bxhat->getMultiVector(0, bDomainThyraMode);
    RCP<MultiVector> xhat2 = bxhat->getMultiVector(1, bDomainThyraMode);
 
 
    // incrementally improve solution vector X
    for (LocalOrdinal run = 0; run < nSweeps; ++run) {
      // 1) calculate current residual
      residual->update(one, *rcpB, zero); // residual = B
      if(InitialGuessIsZero == false || run > 0)
        A_->apply(*rcpX, *residual, Teuchos::NO_TRANS, -one, one);
 
      // 2) solve F * \Delta \tilde{x}_1 = r_1
      //    start with zero guess \Delta \tilde{x}_1
      xtilde1->putScalar(zero);
      xtilde2->putScalar(zero);
      velPredictSmoo_->Apply(*xtilde1, *r1);
 
      // 3) calculate rhs for SchurComp equation
      //    r_2 - D \Delta \tilde{x}_1
      RCP<MultiVector> schurCompRHS = rangeMapExtractor_->getVector(1, rcpB->getNumVectors(), bRangeThyraMode);
      D_->apply(*xtilde1, *schurCompRHS);
 
      schurCompRHS->update(one, *r2, -one);
 
      // 4) solve SchurComp equation
      //    start with zero guess \Delta \tilde{x}_2
      schurCompSmoo_->Apply(*xtilde2, *schurCompRHS);
 
      // 5) scale xtilde2 with omega
      //    store this in xhat2
      xhat2->update(omega, *xtilde2, zero);
 
      // 6) calculate xhat1
      RCP<MultiVector> xhat1_temp = domainMapExtractor_->getVector(0, rcpX->getNumVectors(), bDomainThyraMode);
      G_->apply(*xhat2, *xhat1_temp); // store result temporarely in xtilde1_temp
 
      xhat1->elementWiseMultiply(one/*/omega*/, *diagFinv_, *xhat1_temp, zero);
      xhat1->update(one, *xtilde1, -one);
 
      rcpX->update(one, *bxhat, one);
    }
 
    if (bCopyResultX == true) {
      RCP<const MultiVector> Xmerged = bX->Merge();
      X.update(one, *Xmerged, zero);
    }
 
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  RCP<MueLu::SmootherPrototype<Scalar, LocalOrdinal, GlobalOrdinal, Node> >
  SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Copy () const {
    return rcp( new SimpleSmoother(*this) );
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  std::string SimpleSmoother<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 SimpleSmoother<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;
    }
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  size_t SimpleSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::getNodeSmootherComplexity() const {
    // FIXME: This is a placeholder
    return Teuchos::OrdinalTraits<size_t>::invalid();
  }
 
 
} // namespace MueLu
 
 
#endif /* MUELU_SIMPLESMOOTHER_DEF_HPP_ */