MueLu_BlockedGaussSeidelSmoother_def.hpp

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#ifndef MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_DEF_HPP_
#define MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_DEF_HPP_
 
#include "Teuchos_ArrayViewDecl.hpp"
#include "Teuchos_ScalarTraits.hpp"
 
#include "MueLu_ConfigDefs.hpp"
 
#include <Xpetra_BlockReorderManager.hpp>
#include <Xpetra_Matrix.hpp>
#include <Xpetra_BlockedCrsMatrix.hpp>
#include <Xpetra_ReorderedBlockedCrsMatrix.hpp>
#include <Xpetra_ReorderedBlockedMultiVector.hpp>
#include <Xpetra_MultiVectorFactory.hpp>
 
#include "MueLu_BlockedGaussSeidelSmoother_decl.hpp"
#include "MueLu_Level.hpp"
#include "MueLu_Monitor.hpp"
#include "MueLu_HierarchyUtils.hpp"
#include "MueLu_SmootherBase.hpp"
 
namespace MueLu {
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::BlockedGaussSeidelSmoother()
    : type_("blocked GaussSeidel"), A_(Teuchos::null)
  {
    FactManager_.reserve(10); // TODO fix me!
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::~BlockedGaussSeidelSmoother() {}
 
  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
  RCP<const ParameterList> BlockedGaussSeidelSmoother<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 BGS");
    validParamList->set< LocalOrdinal >          ("Sweeps",             1, "Number of BGS sweeps (default = 1)");
 
    return validParamList;
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::AddFactoryManager(RCP<const FactoryManagerBase> FactManager, int pos) {
    TEUCHOS_TEST_FOR_EXCEPTION(pos < 0, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::AddFactoryManager: parameter \'pos\' must not be negative! error.");
 
    size_t myPos = Teuchos::as<size_t>(pos);
 
    if (myPos < FactManager_.size()) {
      // replace existing entries in FactManager_ vector
      FactManager_.at(myPos) = FactManager;
    } else if(myPos == FactManager_.size()) {
      // append new Factory manager at 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 BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::DeclareInput(Level &currentLevel) const {
    //this->Input(currentLevel, "A");
    // TODO: check me: why is this->Input not freeing properly A in release mode?
    currentLevel.DeclareInput("A",this->GetFactory("A").get());
 
    // 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());
 
      // request "A" for current subblock row (only needed for Thyra mode)
      currentLevel.DeclareInput("A",(*it)->GetFactory("A").get());
    }
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Setup(Level &currentLevel) {
 
    RCP<Teuchos::FancyOStream> out = Teuchos::fancyOStream(Teuchos::rcpFromRef(std::cout));
 
    FactoryMonitor m(*this, "Setup blocked Gauss-Seidel Smoother", currentLevel);
    if (SmootherPrototype::IsSetup() == true) this->GetOStream(Warnings0) << "MueLu::BlockedGaussSeidelSmoother::Setup(): Setup() has already been called";
 
    // extract blocked operator A from current level
    A_ = Factory::Get< RCP<Matrix> >(currentLevel, "A"); // A needed for extracting map extractors
    RCP<BlockedCrsMatrix> bA = Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(A_);
    TEUCHOS_TEST_FOR_EXCEPTION(bA==Teuchos::null, Exceptions::BadCast, "MueLu::BlockedPFactory::Build: input matrix A is not of type BlockedCrsMatrix! error.");
 
    // plausibility check
    TEUCHOS_TEST_FOR_EXCEPTION(bA->Rows() != FactManager_.size(), Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::Setup: number of block rows of A is " << bA->Rows() << " and does not match number of SubFactoryManagers " << FactManager_.size() << ". error.");
    TEUCHOS_TEST_FOR_EXCEPTION(bA->Cols() != FactManager_.size(), Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::Setup: number of block cols of A is " << bA->Cols() << " and does not match number of SubFactoryManagers " << FactManager_.size() << ". error.");
 
    // store map extractors
    rangeMapExtractor_  = bA->getRangeMapExtractor();
    domainMapExtractor_ = bA->getDomainMapExtractor();
 
    // 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);
 
      // extract Smoother for current block row (BGS ordering)
      RCP<const SmootherBase> Smoo = currentLevel.Get< RCP<SmootherBase> >("PreSmoother",(*it)->GetFactory("Smoother").get());
      Inverse_.push_back(Smoo);
 
      // store whether subblock matrix is blocked or not!
      RCP<Matrix> Aii = currentLevel.Get< RCP<Matrix> >("A",(*it)->GetFactory("A").get());
      bIsBlockedOperator_.push_back(Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(Aii)!=Teuchos::null);
    }
 
    SmootherPrototype::IsSetup(true);
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  void BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Apply(MultiVector &X, const MultiVector& B, bool InitialGuessIsZero) const
  {
    TEUCHOS_TEST_FOR_EXCEPTION(SmootherPrototype::IsSetup() == false, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::Apply(): Setup() has not been called");
 
#if 0 // def HAVE_MUELU_DEBUG
    // 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);
    //RCP<BlockedCrsMatrix> bA = Teuchos::rcp_dynamic_cast<BlockedCrsMatrix>(A_);
    if(rcpBDebugB.is_null() == false) {
      //this->GetOStream(Runtime1) << "BlockedGaussSeidel: B is a BlockedMultiVector of size " << B.getMap()->getGlobalNumElements() << " with " << rcpBDebugB->getBlockedMap()->getNumMaps() << " blocks." << std::endl;
      //TEUCHOS_TEST_FOR_EXCEPTION(A_->getRangeMap()->isSameAs(*(B.getMap())) == false, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::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 {
      //this->GetOStream(Runtime1) << "BlockedGaussSeidel: B is a MultiVector of size " << B.getMap()->getGlobalNumElements() << std::endl;
      //TEUCHOS_TEST_FOR_EXCEPTION(bA->getFullRangeMap()->isSameAs(*(B.getMap())) == false, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::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) {
      //this->GetOStream(Runtime1) << "BlockedGaussSeidel: X is a BlockedMultiVector of size " << X.getMap()->getGlobalNumElements() << " with " << rcpBDebugX->getBlockedMap()->getNumMaps() << " blocks." << std::endl;
      //TEUCHOS_TEST_FOR_EXCEPTION(A_->getDomainMap()->isSameAs(*(X.getMap())) == false, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::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 {
      //this->GetOStream(Runtime1) << "BlockedGaussSeidel: X is a MultiVector of size " << X.getMap()->getGlobalNumElements() << std::endl;
      //TEUCHOS_TEST_FOR_EXCEPTION(bA->getFullDomainMap()->isSameAs(*(X.getMap())) == false, Exceptions::RuntimeError, "MueLu::BlockedGaussSeidelSmoother::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
    SC zero = Teuchos::ScalarTraits<SC>::zero(), one = Teuchos::ScalarTraits<SC>::one();
 
    // Input variables used for the rest of the algorithm
    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
 
    RCP<MultiVector> residual = MultiVectorFactory::Build(rcpB->getMap(), rcpB->getNumVectors());
    RCP<MultiVector> tempres = MultiVectorFactory::Build(rcpB->getMap(), rcpB->getNumVectors());
 
    // extract parameters from internal parameter list
    const ParameterList & pL = Factory::GetParameterList();
    LocalOrdinal nSweeps = pL.get<LocalOrdinal>("Sweeps");
    Scalar omega = pL.get<Scalar>("Damping factor");
 
 
    // Clear solution from previos V cycles in case it is still stored
    if( InitialGuessIsZero==true )
      rcpX->putScalar(Teuchos::ScalarTraits<Scalar>::zero());
 
 
    // outer Richardson loop
    for (LocalOrdinal run = 0; run < nSweeps; ++run) {
      // one BGS sweep
      // loop over all block rows
      for(size_t i = 0; i<Inverse_.size(); i++) {
 
        // calculate block residual r = B-A*X
        // note: A_ is the full blocked operator
        residual->update(1.0,*rcpB,0.0); // r = B
        if(InitialGuessIsZero == false || i > 0 || run > 0)
          bA->bgs_apply(*rcpX, *residual, i, Teuchos::NO_TRANS, -1.0, 1.0);
 
        // extract corresponding subvectors from X and residual
        bool bRangeThyraMode =  rangeMapExtractor_->getThyraMode();
        bool bDomainThyraMode = domainMapExtractor_->getThyraMode();
        Teuchos::RCP<MultiVector> Xi = domainMapExtractor_->ExtractVector(rcpX, i, bDomainThyraMode);
        Teuchos::RCP<MultiVector> ri = rangeMapExtractor_->ExtractVector(residual, i, bRangeThyraMode);
        Teuchos::RCP<MultiVector> tXi = domainMapExtractor_->getVector(i, X.getNumVectors(), bDomainThyraMode);
 
        // apply solver/smoother
        Inverse_.at(i)->Apply(*tXi, *ri, false);
 
        // update vector
        Xi->update(omega,*tXi,1.0);  // X_{i+1} = X_i + omega \Delta X_i
 
      }
    }
 
    if (bCopyResultX == true) {
      RCP<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> > BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Copy() const {
    return rcp( new BlockedGaussSeidelSmoother(*this) );
  }
 
  template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
  std::string BlockedGaussSeidelSmoother<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 BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::print(Teuchos::FancyOStream &out, const VerbLevel verbLevel) const {
    MUELU_DESCRIBE;
 
    // extract parameters from internal parameter list
    const ParameterList & pL = Factory::GetParameterList();
    LocalOrdinal nSweeps = pL.get<LocalOrdinal>("Sweeps");
    Scalar omega = pL.get<Scalar>("Damping factor");
 
    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 BlockedGaussSeidelSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::getNodeSmootherComplexity() const {
    // FIXME: This is a placeholder
    return Teuchos::OrdinalTraits<size_t>::invalid();
  }
 
} // namespace MueLu
 
#endif /* MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_DEF_HPP_ */