MueLu_TopSmootherFactory_def.hpp

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/*
 * MueLu_TopSmootherFactory_def.hpp
 *
 *  Created on: Jan 25, 2016
 *      Author: tawiesn
 */

#ifndef PACKAGES_MUELU_SRC_MUECENTRAL_MUELU_TOPSMOOTHERFACTORY_DEF_HPP_
#define PACKAGES_MUELU_SRC_MUECENTRAL_MUELU_TOPSMOOTHERFACTORY_DEF_HPP_

#include "MueLu_ConfigDefs.hpp"

//#include "MueLu_FactoryManager_fwd.hpp"
#include "MueLu_FactoryManagerBase.hpp"
//#include "MueLu_HierarchyHelpers_fwd.hpp"
#include "MueLu_TopSmootherFactory.hpp"
#include "MueLu_Level_fwd.hpp"
#include "MueLu_SingleLevelFactoryBase.hpp"
//#include "MueLu_SmootherBase_fwd.hpp"
#include "MueLu_SmootherFactory.hpp"
#include "MueLu_SmootherPrototype.hpp"
//#include "MueLu_Hierarchy_fwd.hpp"
//#include "MueLu_HierarchyManager_fwd.hpp"

namespace MueLu {
  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
  TopSmootherFactory<Scalar, LocalOrdinal, GlobalOrdinal, Node>::TopSmootherFactory(RCP<const FactoryManagerBase> parentFactoryManager, const std::string& varName) {
    TEUCHOS_TEST_FOR_EXCEPTION(varName != "CoarseSolver" && varName != "Smoother", Exceptions::RuntimeError, "varName should be either \"CoarseSolver\" or \"Smoother\"");

    if (varName == "CoarseSolver") {
      // For coarsest level, we only need one smoother/solver
      // If a user wants to do something weird there (like, solve coarsest system by using 2 forward
      // GS and 1 backward GS), one can use MergedSmoother
      RCP<const FactoryBase> coarseSolverFactory = parentFactoryManager->GetFactory("CoarseSolver");
      RCP<const SmootherFactory> coarseSmootherFactory = Teuchos::rcp_dynamic_cast<const SmootherFactory>(coarseSolverFactory);
      if (coarseSmootherFactory != Teuchos::null) {
        RCP<SmootherPrototype> preProto;
        RCP<SmootherPrototype> postProto;
        coarseSmootherFactory->GetSmootherPrototypes(preProto, postProto);

        if (preProto == postProto)
          preSmootherFact_  = parentFactoryManager->GetFactory("CoarseSolver");
        else {
          // check whether pre- and/or post-smoothing is desired on coarsest level
          if(preProto != Teuchos::null)
            preSmootherFact_  = parentFactoryManager->GetFactory("CoarseSolver");
          if(postProto != Teuchos::null)
            postSmootherFact_  = parentFactoryManager->GetFactory("CoarseSolver");
        }
      }
      else  // default handling: get default direct solver as presmoother on coarsest level
        preSmootherFact_  = parentFactoryManager->GetFactory("CoarseSolver");

    } else {
      preSmootherFact_  = parentFactoryManager->GetFactory("PreSmoother");
      postSmootherFact_ = parentFactoryManager->GetFactory("PostSmoother");
    }
  }

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

  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
  void TopSmootherFactory<Scalar, LocalOrdinal, GlobalOrdinal, Node>::DeclareInput(Level & level) const {
    if (preSmootherFact_  != Teuchos::null)
      level.DeclareInput("PreSmoother",  preSmootherFact_.get());
    if (postSmootherFact_ != Teuchos::null)
      level.DeclareInput("PostSmoother", postSmootherFact_.get());
  }

  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
  void TopSmootherFactory<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Build(Level & level) const {
    if (preSmootherFact_.is_null() && postSmootherFact_.is_null())
      return;

    // NOTE 1: We need to set at least some keep flag for the smoothers, otherwise it is going to be removed as soon as all requests are released.
    // We choose to set the Final flag for the data. In addition, we allow this data to be retrieved by only using the name by the means
    // of using NoFactory. However, any data set with NoFactory gets UserData flag by default. We don't really want that flag, so we remove it.

    // NOTE 2: some smoother factories are tricky (see comments in MueLu::SmootherFactory
    // Sometimes, we don't know whether the factory is able to generate "PreSmoother" or "PostSmoother"
    // For the SmootherFactory, however, we are able to check that.

    if (!preSmootherFact_.is_null()) {
      // Checking for null is not sufficient, as SmootherFactory(null, something) does not generate "PreSmoother"
      bool isAble = true;
      RCP<const SmootherFactory> s = rcp_dynamic_cast<const SmootherFactory>(preSmootherFact_);
      if (!s.is_null()) {
        RCP<SmootherPrototype> pre, post;
        s->GetSmootherPrototypes(pre, post);
        if (pre.is_null())
          isAble = false;
      } else {
        // We assume that  if presmoother factory is not SmootherFactory, it *is* able to generate "PreSmoother"
      }

      if (isAble) {
        RCP<SmootherBase> Pre  = level.Get<RCP<SmootherBase> >("PreSmoother", preSmootherFact_.get());

        level.Set           ("PreSmoother", Pre, NoFactory::get());

        level.AddKeepFlag   ("PreSmoother", NoFactory::get(), MueLu::Final);
        level.RemoveKeepFlag("PreSmoother", NoFactory::get(), MueLu::UserData);
      }
    }

    if (!postSmootherFact_.is_null()) {
      // Checking for null is not sufficient, as SmootherFactory(something, null) does not generate "PostSmoother"
      bool isAble = true;
      RCP<const SmootherFactory> s = rcp_dynamic_cast<const SmootherFactory>(postSmootherFact_);
      if (!s.is_null()) {
        RCP<SmootherPrototype> pre, post;
        s->GetSmootherPrototypes(pre, post);
        if (post.is_null())
          isAble = false;
      } else {
        // We assume that  if presmoother factory is not SmootherFactory, it *is* able to generate "PreSmoother"
      }

      if (isAble) {
        RCP<SmootherBase> Post = level.Get<RCP<SmootherBase> >("PostSmoother", postSmootherFact_.get());

        level.Set           ("PostSmoother", Post, NoFactory::get());

        level.AddKeepFlag   ("PostSmoother", NoFactory::get(), MueLu::Final);
        level.RemoveKeepFlag("PostSmoother", NoFactory::get(), MueLu::UserData);
      }
    }
  }
}


#endif /* PACKAGES_MUELU_SRC_MUECENTRAL_MUELU_TOPSMOOTHERFACTORY_DEF_HPP_ */