MueLu_BlockedGaussSeidelSmoother_def.hpp

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// @HEADER
// *****************************************************************************
//        MueLu: A package for multigrid based preconditioning
//
// Copyright 2012 NTESS and the MueLu contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#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_ */