Thyra_BelosLinearOpWithSolveFactory_def.hpp

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//         Stratimikos: Thyra-based strategies for linear solvers
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#ifndef THYRA_BELOS_LINEAR_OP_WITH_SOLVE_FACTORY_HPP
#define THYRA_BELOS_LINEAR_OP_WITH_SOLVE_FACTORY_HPP
 
 
#include "Thyra_BelosLinearOpWithSolveFactory_decl.hpp"
#include "Thyra_BelosLinearOpWithSolve.hpp"
#include "Thyra_ScaledAdjointLinearOpBase.hpp"
 
#include "BelosBlockGmresSolMgr.hpp"
#include "BelosPseudoBlockGmresSolMgr.hpp"
#include "BelosBlockCGSolMgr.hpp"
#include "BelosPseudoBlockCGSolMgr.hpp"
#include "BelosPseudoBlockStochasticCGSolMgr.hpp"
#include "BelosGCRODRSolMgr.hpp"
#include "BelosRCGSolMgr.hpp"
#include "BelosMinresSolMgr.hpp"
#include "BelosTFQMRSolMgr.hpp"
#include "BelosBiCGStabSolMgr.hpp"
#include "BelosFixedPointSolMgr.hpp"
 
#include "BelosThyraAdapter.hpp"
#include "Teuchos_VerboseObjectParameterListHelpers.hpp"
#include "Teuchos_StandardParameterEntryValidators.hpp"
#include "Teuchos_ParameterList.hpp"
#include "Teuchos_dyn_cast.hpp"
#include "Teuchos_ValidatorXMLConverterDB.hpp"
#include "Teuchos_StandardValidatorXMLConverters.hpp"
 
 
namespace Thyra {
 
 
// Parameter names for Parameter List
 
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::SolverType_name = "Solver Type";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::SolverType_default = "Pseudo Block GMRES";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::SolverTypes_name = "Solver Types";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::BlockGMRES_name = "Block GMRES";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::PseudoBlockGMRES_name = "Pseudo Block GMRES";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::BlockCG_name = "Block CG";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::PseudoBlockCG_name = "Pseudo Block CG";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::PseudoBlockStochasticCG_name = "Pseudo Block Stochastic CG";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::GCRODR_name = "GCRODR";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::RCG_name = "RCG";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::MINRES_name = "MINRES";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::TFQMR_name = "TFQMR";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::BiCGStab_name = "BiCGStab";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::FixedPoint_name = "Fixed Point";
template<class Scalar>
const std::string BelosLinearOpWithSolveFactory<Scalar>::ConvergenceTestFrequency_name = "Convergence Test Frequency";
 
namespace {
const std::string LeftPreconditionerIfUnspecified_name = "Left Preconditioner If Unspecified";
}
 
// Constructors/initializers/accessors
 
 
template<class Scalar>
BelosLinearOpWithSolveFactory<Scalar>::BelosLinearOpWithSolveFactory()
  :solverType_(SOLVER_TYPE_PSEUDO_BLOCK_GMRES),
   convergenceTestFrequency_(1)
{
  updateThisValidParamList();
}
 
 
template<class Scalar>
BelosLinearOpWithSolveFactory<Scalar>::BelosLinearOpWithSolveFactory(
  const RCP<PreconditionerFactoryBase<Scalar> > &precFactory
  )
  :solverType_(SOLVER_TYPE_PSEUDO_BLOCK_GMRES)
{
  this->setPreconditionerFactory(precFactory, "");
}
 
 
// Overridden from LinearOpWithSolveFactoryBase
 
 
template<class Scalar>
bool BelosLinearOpWithSolveFactory<Scalar>::acceptsPreconditionerFactory() const
{
  return true;
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::setPreconditionerFactory(
  const RCP<PreconditionerFactoryBase<Scalar> > &precFactory,
  const std::string &precFactoryName
  )
{
  TEUCHOS_TEST_FOR_EXCEPT(!precFactory.get());
  RCP<const Teuchos::ParameterList>
    precFactoryValidPL = precFactory->getValidParameters();
  const std::string _precFactoryName =
    ( precFactoryName != ""
      ? precFactoryName
      : ( precFactoryValidPL.get() ? precFactoryValidPL->name() : "GENERIC PRECONDITIONER FACTORY" )
      );
  precFactory_ = precFactory;
  precFactoryName_ = _precFactoryName;
  updateThisValidParamList();
}
 
 
template<class Scalar>
RCP<PreconditionerFactoryBase<Scalar> >
BelosLinearOpWithSolveFactory<Scalar>::getPreconditionerFactory() const
{
  return precFactory_;
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::unsetPreconditionerFactory(
  RCP<PreconditionerFactoryBase<Scalar> > *precFactory,
  std::string *precFactoryName
  )
{
  if(precFactory) *precFactory = precFactory_;
  if(precFactoryName) *precFactoryName = precFactoryName_;
  precFactory_ = Teuchos::null;
  precFactoryName_ = "";
  updateThisValidParamList();
}
 
 
template<class Scalar>
bool BelosLinearOpWithSolveFactory<Scalar>::isCompatible(
  const LinearOpSourceBase<Scalar> &fwdOpSrc
  ) const
{
  if(precFactory_.get())
    return precFactory_->isCompatible(fwdOpSrc);
  return true; // Without a preconditioner, we are compatible with all linear operators!
}
 
 
template<class Scalar>
RCP<LinearOpWithSolveBase<Scalar> >
BelosLinearOpWithSolveFactory<Scalar>::createOp() const
{
  return Teuchos::rcp(new BelosLinearOpWithSolve<Scalar>());
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::initializeOp(
  const RCP<const LinearOpSourceBase<Scalar> > &fwdOpSrc,
  LinearOpWithSolveBase<Scalar> *Op,
  const ESupportSolveUse supportSolveUse
  ) const
{
  using Teuchos::null;
  initializeOpImpl(fwdOpSrc,null,null,false,Op,supportSolveUse);
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::initializeAndReuseOp(
  const RCP<const LinearOpSourceBase<Scalar> > &fwdOpSrc,
  LinearOpWithSolveBase<Scalar> *Op
  ) const
{
  using Teuchos::null;
  initializeOpImpl(fwdOpSrc,null,null,true,Op,SUPPORT_SOLVE_UNSPECIFIED);
}
 
 
template<class Scalar>
bool BelosLinearOpWithSolveFactory<Scalar>::supportsPreconditionerInputType(
  const EPreconditionerInputType precOpType
  ) const
{
  if(precFactory_.get())
    return true;
  return (precOpType==PRECONDITIONER_INPUT_TYPE_AS_OPERATOR);
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::initializePreconditionedOp(
  const RCP<const LinearOpSourceBase<Scalar> > &fwdOpSrc,
  const RCP<const PreconditionerBase<Scalar> > &prec,
  LinearOpWithSolveBase<Scalar> *Op,
  const ESupportSolveUse supportSolveUse
  ) const
{
  using Teuchos::null;
  initializeOpImpl(fwdOpSrc,null,prec,false,Op,supportSolveUse);
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::initializeApproxPreconditionedOp(
  const RCP<const LinearOpSourceBase<Scalar> > &fwdOpSrc,
  const RCP<const LinearOpSourceBase<Scalar> > &approxFwdOpSrc,
  LinearOpWithSolveBase<Scalar> *Op,
  const ESupportSolveUse supportSolveUse
  ) const
{
  using Teuchos::null;
  initializeOpImpl(fwdOpSrc,approxFwdOpSrc,null,false,Op,supportSolveUse);
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::uninitializeOp(
  LinearOpWithSolveBase<Scalar> *Op,
  RCP<const LinearOpSourceBase<Scalar> > *fwdOpSrc,
  RCP<const PreconditionerBase<Scalar> > *prec,
  RCP<const LinearOpSourceBase<Scalar> > *approxFwdOpSrc,
  ESupportSolveUse *supportSolveUse
  ) const
{
#ifdef TEUCHOS_DEBUG
  TEUCHOS_TEST_FOR_EXCEPT(Op==NULL);
#endif
  BelosLinearOpWithSolve<Scalar>
    &belosOp = Teuchos::dyn_cast<BelosLinearOpWithSolve<Scalar> >(*Op);
  RCP<const LinearOpSourceBase<Scalar> > 
    _fwdOpSrc = belosOp.extract_fwdOpSrc();
  RCP<const PreconditionerBase<Scalar> >
    _prec = ( belosOp.isExternalPrec() ? belosOp.extract_prec() : Teuchos::null );
  // Note: above we only extract the preconditioner if it was passed in
  // externally.  Otherwise, we need to hold on to it so that we can reuse it
  // in the next initialization.
  RCP<const LinearOpSourceBase<Scalar> >
    _approxFwdOpSrc = belosOp.extract_approxFwdOpSrc();
  ESupportSolveUse
    _supportSolveUse = belosOp.supportSolveUse();
  if(fwdOpSrc) *fwdOpSrc = _fwdOpSrc;
  if(prec) *prec = _prec;
  if(approxFwdOpSrc) *approxFwdOpSrc = _approxFwdOpSrc;
  if(supportSolveUse) *supportSolveUse = _supportSolveUse;
}
 
 
// Overridden from ParameterListAcceptor
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::setParameterList(
  RCP<Teuchos::ParameterList> const& paramList
  )
{
  TEUCHOS_TEST_FOR_EXCEPT(paramList.get()==NULL);
  paramList->validateParametersAndSetDefaults(*this->getValidParameters(), 1);
  paramList_ = paramList;
  solverType_ =
    Teuchos::getIntegralValue<EBelosSolverType>(*paramList_, SolverType_name);
  convergenceTestFrequency_ =
    Teuchos::getParameter<int>(*paramList_, ConvergenceTestFrequency_name);
  Teuchos::readVerboseObjectSublist(&*paramList_,this);
}
 
 
template<class Scalar>
RCP<Teuchos::ParameterList>
BelosLinearOpWithSolveFactory<Scalar>::getNonconstParameterList()
{
  return paramList_;
}
 
 
template<class Scalar>
RCP<Teuchos::ParameterList>
BelosLinearOpWithSolveFactory<Scalar>::unsetParameterList()
{
  RCP<Teuchos::ParameterList> _paramList = paramList_;
  paramList_ = Teuchos::null;
  return _paramList;
}
 
 
template<class Scalar>
RCP<const Teuchos::ParameterList>
BelosLinearOpWithSolveFactory<Scalar>::getParameterList() const
{
  return paramList_;
}
 
 
template<class Scalar>
RCP<const Teuchos::ParameterList>
BelosLinearOpWithSolveFactory<Scalar>::getValidParameters() const
{
  return thisValidParamList_;
}
 
 
// Public functions overridden from Teuchos::Describable
 
 
template<class Scalar>
std::string BelosLinearOpWithSolveFactory<Scalar>::description() const
{
  std::ostringstream oss;
  oss << "Thyra::BelosLinearOpWithSolveFactory";
  //oss << "{";
  // ToDo: Fill this in some!
  //oss << "}";
  return oss.str();
}
 
 
// private
 
 
template<class Scalar>
RCP<const Teuchos::ParameterList>
BelosLinearOpWithSolveFactory<Scalar>::generateAndGetValidParameters()
{
  using Teuchos::as;
  using Teuchos::tuple;
  using Teuchos::setStringToIntegralParameter;
Teuchos::ValidatorXMLConverterDB::addConverter(
  Teuchos::DummyObjectGetter<
    Teuchos::StringToIntegralParameterEntryValidator<EBelosSolverType> 
  >::getDummyObject(),
  Teuchos::DummyObjectGetter<Teuchos::StringToIntegralValidatorXMLConverter<
    EBelosSolverType> >::getDummyObject());
 
  typedef MultiVectorBase<Scalar> MV_t;
  typedef LinearOpBase<Scalar> LO_t;
  static RCP<Teuchos::ParameterList> validParamList;
  if(validParamList.get()==NULL) {
    validParamList = Teuchos::rcp(new Teuchos::ParameterList("BelosLinearOpWithSolveFactory"));
    setStringToIntegralParameter<EBelosSolverType>(
      SolverType_name, SolverType_default,
      "Type of linear solver algorithm to use.",
      tuple<std::string>(
        "Block GMRES",
        "Pseudo Block GMRES",
        "Block CG",
        "Pseudo Block CG",
        "Pseudo Block Stochastic CG",
        "GCRODR",
        "RCG",
        "MINRES",
        "TFQMR",
        "BiCGStab",
        "Fixed Point"
        ),
      tuple<std::string>(
        "Block GMRES solver for nonsymmetric linear systems.  It can also solve "
        "single right-hand side systems, and can also perform Flexible GMRES "
        "(where the preconditioner may change at every iteration, for example "
        "for inner-outer iterations), by setting options in the \"Block GMRES\" "
        "sublist.",
 
        "GMRES solver for nonsymmetric linear systems, that performs single "
        "right-hand side solves on multiple right-hand sides at once.  It "
        "exploits operator multivector multiplication in order to amortize "
        "global communication costs.  Individual linear systems are deflated "
        "out as they are solved.",
 
        "Block CG solver for symmetric (Hermitian in complex arithmetic) "
        "positive definite linear systems.  It can also solve single "
        "right-hand-side systems.",
 
        "CG solver that performs single right-hand side CG on multiple right-hand "
        "sides at once.  It exploits operator multivector multiplication in order "
        "to amortize global communication costs.  Individual linear systems are "
        "deflated out as they are solved.",
 
        "stochastic CG solver that performs single right-hand side CG on multiple right-hand "
        "sides at once.  It exploits operator multivector multiplication in order "
        "to amortize global communication costs.  Individual linear systems are "
        "deflated out as they are solved. [EXPERIMENTAL]",
 
        "Variant of GMRES that performs subspace recycling to accelerate "
        "convergence for sequences of solves with related linear systems.  "
  "Individual linear systems are deflated out as they are solved.  "
  "The current implementation only supports real-valued Scalar types.",
 
        "CG solver for symmetric (Hermitian in complex arithmetic) positive "
        "definite linear systems, that performs subspace recycling to "
        "accelerate convergence for sequences of related linear systems.",
 
        "MINRES solver for symmetric indefinite linear systems.  It performs "
        "single-right-hand-side solves on multiple right-hand sides sequentially.",
 
        "TFQMR (Transpose-Free QMR) solver for nonsymmetric linear systems.",
 
        "BiCGStab solver for nonsymmetric linear systems.",
 
        "Fixed point iteration"
        ),
      tuple<EBelosSolverType>(
        SOLVER_TYPE_BLOCK_GMRES,
        SOLVER_TYPE_PSEUDO_BLOCK_GMRES,
        SOLVER_TYPE_BLOCK_CG,
        SOLVER_TYPE_PSEUDO_BLOCK_CG,
        SOLVER_TYPE_PSEUDO_BLOCK_STOCHASTIC_CG,
        SOLVER_TYPE_GCRODR,
        SOLVER_TYPE_RCG,
        SOLVER_TYPE_MINRES,
        SOLVER_TYPE_TFQMR,
        SOLVER_TYPE_BICGSTAB,
        SOLVER_TYPE_FIXEDPOINT
        ),
      &*validParamList
      );
    validParamList->set(ConvergenceTestFrequency_name, as<int>(1),
      "Number of linear solver iterations to skip between applying"
      " user-defined convergence test.");
    validParamList->set(
      LeftPreconditionerIfUnspecified_name, false,
      "If the preconditioner does not specify if it is left or right, and this\n"
      "option is set to true, put the preconditioner on the left side.\n"
      "Historically, preconditioning is on the right. Some solvers may not\n"
      "support left preconditioning.");
    Teuchos::ParameterList
      &solverTypesSL = validParamList->sublist(SolverTypes_name);
    {
      Belos::BlockGmresSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(BlockGMRES_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::PseudoBlockGmresSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(PseudoBlockGMRES_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::BlockCGSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(BlockCG_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::PseudoBlockCGSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(PseudoBlockCG_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::PseudoBlockStochasticCGSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(PseudoBlockStochasticCG_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::GCRODRSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(GCRODR_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::RCGSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(RCG_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::MinresSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(MINRES_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::TFQMRSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(TFQMR_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::BiCGStabSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(BiCGStab_name).setParameters(
        *mgr.getValidParameters()
        );
    }
    {
      Belos::FixedPointSolMgr<Scalar,MV_t,LO_t> mgr;
      solverTypesSL.sublist(FixedPoint_name).setParameters(
        *mgr.getValidParameters()
        );
    }
  }
  return validParamList;
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::updateThisValidParamList()
{
  thisValidParamList_ = Teuchos::rcp(
    new Teuchos::ParameterList(*generateAndGetValidParameters())
    );
  Teuchos::setupVerboseObjectSublist(&*thisValidParamList_);
}
 
 
template<class Scalar>
void BelosLinearOpWithSolveFactory<Scalar>::initializeOpImpl(
  const RCP<const LinearOpSourceBase<Scalar> > &fwdOpSrc,
  const RCP<const LinearOpSourceBase<Scalar> > &approxFwdOpSrc,
  const RCP<const PreconditionerBase<Scalar> > &prec_in,
  const bool reusePrec,
  LinearOpWithSolveBase<Scalar> *Op,
  const ESupportSolveUse supportSolveUse
  ) const
{
 
  using Teuchos::rcp;
  using Teuchos::set_extra_data;
  typedef Teuchos::ScalarTraits<Scalar> ST;
  typedef MultiVectorBase<Scalar> MV_t;
  typedef LinearOpBase<Scalar> LO_t;
 
  const RCP<Teuchos::FancyOStream> out = this->getOStream();
  const Teuchos::EVerbosityLevel verbLevel = this->getVerbLevel();
  Teuchos::OSTab tab(out);
  if(out.get() && static_cast<int>(verbLevel) > static_cast<int>(Teuchos::VERB_LOW))
    *out << "\nEntering Thyra::BelosLinearOpWithSolveFactory<"<<ST::name()<<">::initializeOpImpl(...) ...\n";
 
  // These lines are changing the verbosity of the preconditioner, which has its own verbose object list,
  // so I am commenting these out, as it is not the job of the linear solver to dictate preconditioner verbosity.
  //typedef Teuchos::VerboseObjectTempState<PreconditionerFactoryBase<Scalar> > VOTSPF;
  //VOTSPF precFactoryOutputTempState(precFactory_,out,verbLevel);
  
  TEUCHOS_TEST_FOR_EXCEPT(Op==NULL);
  TEUCHOS_TEST_FOR_EXCEPT(fwdOpSrc.get()==NULL);
  TEUCHOS_TEST_FOR_EXCEPT(fwdOpSrc->getOp().get()==NULL);
  RCP<const LinearOpBase<Scalar> >
    fwdOp = fwdOpSrc->getOp(),
    approxFwdOp = ( approxFwdOpSrc.get() ? approxFwdOpSrc->getOp() : Teuchos::null );
 
  //
  // Get the BelosLinearOpWithSolve interface
  //
 
  BelosLinearOpWithSolve<Scalar>
    *belosOp = &Teuchos::dyn_cast<BelosLinearOpWithSolve<Scalar> >(*Op);
 
  //
  // Get/Create the preconditioner
  //
 
  RCP<PreconditionerBase<Scalar> > myPrec = Teuchos::null;
  RCP<const PreconditionerBase<Scalar> > prec = Teuchos::null;
  if(prec_in.get()) {
    // Use an externally defined preconditioner
    prec = prec_in;
  }
  else {
    // Try and generate a preconditioner on our own
    if(precFactory_.get()) {
      myPrec =
        ( !belosOp->isExternalPrec()
          ? Teuchos::rcp_const_cast<PreconditionerBase<Scalar> >(belosOp->extract_prec())
          : Teuchos::null
          );
      bool hasExistingPrec = false;
      if(myPrec.get()) {
        hasExistingPrec = true;
        // ToDo: Get the forward operator and validate that it is the same
        // operator that is used here!
      }
      else {
        hasExistingPrec = false;
        myPrec = precFactory_->createPrec();
      }
      if( hasExistingPrec && reusePrec ) {
        // Just reuse the existing preconditioner again!
      }
      else {
        // Update the preconditioner
        if(approxFwdOp.get())
          precFactory_->initializePrec(approxFwdOpSrc,&*myPrec);
        else
          precFactory_->initializePrec(fwdOpSrc,&*myPrec);
      }
      prec = myPrec;
    }
  }
 
  //
  // Uninitialize the current solver object
  //
 
  bool oldIsExternalPrec = false;
  RCP<Belos::LinearProblem<Scalar,MV_t,LO_t> > oldLP = Teuchos::null;
  RCP<Belos::SolverManager<Scalar,MV_t,LO_t> > oldIterSolver = Teuchos::null;
  RCP<const LinearOpSourceBase<Scalar> > oldFwdOpSrc = Teuchos::null;
  RCP<const LinearOpSourceBase<Scalar> > oldApproxFwdOpSrc = Teuchos::null;   
  ESupportSolveUse oldSupportSolveUse = SUPPORT_SOLVE_UNSPECIFIED;
 
  belosOp->uninitialize( &oldLP, NULL, &oldIterSolver, &oldFwdOpSrc,
    NULL, &oldIsExternalPrec, &oldApproxFwdOpSrc, &oldSupportSolveUse );
 
  //
  // Create the Belos linear problem
  // NOTE:  If one exists already, reuse it.
  //
 
  typedef Belos::LinearProblem<Scalar,MV_t,LO_t> LP_t;
  RCP<LP_t> lp;
  if (oldLP != Teuchos::null) {
    lp = oldLP;
  }
  else {
    lp = rcp(new LP_t());
  }
 
  //
  // Set the operator
  //
 
  lp->setOperator(fwdOp);
 
  //
  // Set the preconditioner
  //
 
  if(prec.get()) {
    RCP<const LinearOpBase<Scalar> > unspecified = prec->getUnspecifiedPrecOp();
    RCP<const LinearOpBase<Scalar> > left = prec->getLeftPrecOp();
    RCP<const LinearOpBase<Scalar> > right = prec->getRightPrecOp();
    TEUCHOS_TEST_FOR_EXCEPTION(
      !( left.get() || right.get() || unspecified.get() ), std::logic_error
      ,"Error, at least one preconditoner linear operator objects must be set!"
      );
    if (nonnull(unspecified)) {
      if (paramList_->get<bool>(LeftPreconditionerIfUnspecified_name, false))
        lp->setLeftPrec(unspecified);
      else
        lp->setRightPrec(unspecified);
    }
    else if (nonnull(left)) {
      lp->setLeftPrec(left);
    }
    else if (nonnull(right)) {
      lp->setRightPrec(right);
    }
    else {
      // Set a left, right or split preconditioner
      TEUCHOS_TEST_FOR_EXCEPTION(
        nonnull(left) && nonnull(right),std::logic_error
        ,"Error, we can not currently handle split preconditioners!"
        );
    }
  }
  if(myPrec.get()) {
    set_extra_data<RCP<PreconditionerBase<Scalar> > >(myPrec,"Belos::InternalPrec",
      Teuchos::inOutArg(lp), Teuchos::POST_DESTROY, false);
  }
  else if(prec.get()) {
    set_extra_data<RCP<const PreconditionerBase<Scalar> > >(prec,"Belos::ExternalPrec",
      Teuchos::inOutArg(lp), Teuchos::POST_DESTROY, false);
  }
 
  //
  // Generate the parameter list.
  //
 
  typedef Belos::SolverManager<Scalar,MV_t,LO_t> IterativeSolver_t;
  RCP<IterativeSolver_t> iterativeSolver = Teuchos::null;
  RCP<Teuchos::ParameterList> solverPL = Teuchos::rcp( new Teuchos::ParameterList() );
  
  switch(solverType_) {
    case SOLVER_TYPE_BLOCK_GMRES: 
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &gmresPL = solverTypesPL.sublist(BlockGMRES_name);
        solverPL = Teuchos::rcp( &gmresPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      } 
      else {
        iterativeSolver = rcp(new Belos::BlockGmresSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_PSEUDO_BLOCK_GMRES:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &pbgmresPL = solverTypesPL.sublist(PseudoBlockGMRES_name);
        solverPL = Teuchos::rcp( &pbgmresPL, false );
      }
      // 
      // Create the solver
      // 
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::PseudoBlockGmresSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_BLOCK_CG:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &cgPL = solverTypesPL.sublist(BlockCG_name);
        solverPL = Teuchos::rcp( &cgPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::BlockCGSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_PSEUDO_BLOCK_CG:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &pbcgPL = solverTypesPL.sublist(PseudoBlockCG_name);
        solverPL = Teuchos::rcp( &pbcgPL, false );
      }
      // 
      // Create the solver
      // 
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::PseudoBlockCGSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_PSEUDO_BLOCK_STOCHASTIC_CG:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &pbcgPL = solverTypesPL.sublist(PseudoBlockStochasticCG_name);
        solverPL = Teuchos::rcp( &pbcgPL, false );
      }
      // 
      // Create the solver
      // 
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::PseudoBlockStochasticCGSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_GCRODR:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &gcrodrPL = solverTypesPL.sublist(GCRODR_name);
        solverPL = Teuchos::rcp( &gcrodrPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      } 
      else {
        iterativeSolver = rcp(new Belos::GCRODRSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_RCG:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &rcgPL = solverTypesPL.sublist(RCG_name);
        solverPL = Teuchos::rcp( &rcgPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      } 
      else {
        iterativeSolver = rcp(new Belos::RCGSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_MINRES:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &minresPL = solverTypesPL.sublist(MINRES_name);
        solverPL = Teuchos::rcp( &minresPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::MinresSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_TFQMR:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &minresPL = solverTypesPL.sublist(TFQMR_name);
        solverPL = Teuchos::rcp( &minresPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::TFQMRSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_BICGSTAB:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &bicgstabPL = solverTypesPL.sublist(BiCGStab_name);
        solverPL = Teuchos::rcp( &bicgstabPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::BiCGStabSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
    case SOLVER_TYPE_FIXEDPOINT:
    {
      // Set the PL
      if(paramList_.get()) {
        Teuchos::ParameterList &solverTypesPL = paramList_->sublist(SolverTypes_name);
        Teuchos::ParameterList &fixedPointPL = solverTypesPL.sublist(FixedPoint_name);
        solverPL = Teuchos::rcp( &fixedPointPL, false );
      }
      // Create the solver
      if (oldIterSolver != Teuchos::null) {
        iterativeSolver = oldIterSolver;
        iterativeSolver->setProblem( lp );
        iterativeSolver->setParameters( solverPL );
      }
      else {
        iterativeSolver = rcp(new Belos::FixedPointSolMgr<Scalar,MV_t,LO_t>(lp,solverPL));
      }
      break;
    }
 
    default:
    {
      TEUCHOS_TEST_FOR_EXCEPT(true);
    }
  }
 
  //
  // Initialize the LOWS object
  //
 
  belosOp->initialize(
    lp, solverPL, iterativeSolver,
    fwdOpSrc, prec, myPrec.get()==NULL, approxFwdOpSrc,
    supportSolveUse, convergenceTestFrequency_
    );
  belosOp->setOStream(out);
  belosOp->setVerbLevel(verbLevel);
#ifdef TEUCHOS_DEBUG
  if(paramList_.get()) {
    // Make sure we read the list correctly
    paramList_->validateParameters(*this->getValidParameters(),1); // Validate 0th and 1st level deep
  }
#endif
  if(out.get() && static_cast<int>(verbLevel) > static_cast<int>(Teuchos::VERB_LOW))
    *out << "\nLeaving Thyra::BelosLinearOpWithSolveFactory<"<<ST::name()<<">::initializeOpImpl(...) ...\n";
  
}
 
 
} // namespace Thyra
 
 
#endif // THYRA_BELOS_LINEAR_OP_WITH_SOLVE_FACTORY_HPP