BelosGmresPolySolMgr.hpp

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// @HEADER
// *****************************************************************************
//                 Belos: Block Linear Solvers Package
//
// Copyright 2004-2016 NTESS and the Belos contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER
//

#ifndef BELOS_GMRES_POLY_SOLMGR_HPP
#define BELOS_GMRES_POLY_SOLMGR_HPP


#include "BelosConfigDefs.hpp"
#include "BelosTypes.hpp"

#include "BelosLinearProblem.hpp"
#include "BelosSolverManager.hpp"
#include "BelosGmresPolyOp.hpp"
#include "BelosSolverFactory_Generic.hpp"
#include "BelosOrthoManagerFactory.hpp"
#include "Teuchos_as.hpp"
#ifdef BELOS_TEUCHOS_TIME_MONITOR
#include "Teuchos_TimeMonitor.hpp"
#endif

namespace Belos {



class GmresPolySolMgrLinearProblemFailure : public BelosError {public:
  GmresPolySolMgrLinearProblemFailure(const std::string& what_arg) : BelosError(what_arg)
    {}};

class GmresPolySolMgrPolynomialFailure : public BelosError {public:
  GmresPolySolMgrPolynomialFailure(const std::string& what_arg) : BelosError(what_arg)
    {}};

//
//

template<class ScalarType, class MV, class OP>
class GmresPolySolMgr : public SolverManager<ScalarType,MV,OP> {
private:

  typedef typename Teuchos::ScalarTraits<ScalarType>::magnitudeType MagnitudeType;

  typedef Teuchos::ScalarTraits<MagnitudeType> MTS;
  typedef Belos::GmresPolyOp<ScalarType,MV,OP> gmres_poly_t;
  typedef Belos::GmresPolyMv<ScalarType,MV>    gmres_poly_mv_t;

public:



  GmresPolySolMgr();

  GmresPolySolMgr( const Teuchos::RCP<LinearProblem<ScalarType,MV,OP> > &problem,
    const Teuchos::RCP<Teuchos::ParameterList> &pl );

  virtual ~GmresPolySolMgr() {};

  Teuchos::RCP<SolverManager<ScalarType, MV, OP> > clone () const override {
    return Teuchos::rcp(new GmresPolySolMgr<ScalarType,MV,OP>);
  }



  const LinearProblem<ScalarType,MV,OP>& getProblem() const override {
    return *problem_;
  }

  Teuchos::RCP<const Teuchos::ParameterList> getValidParameters() const override;

  Teuchos::RCP<const Teuchos::ParameterList> getCurrentParameters() const override { return params_; }

    MagnitudeType achievedTol() const override {
      return achievedTol_;
    }

  Teuchos::Array<Teuchos::RCP<Teuchos::Time> > getTimers() const {
    return Teuchos::tuple(timerPoly_);
  }

  int getNumIters() const override {
    return numIters_;
  }

  bool isLOADetected() const override { return loaDetected_; }




  void setProblem( const Teuchos::RCP<LinearProblem<ScalarType,MV,OP> > &problem ) override { problem_ = problem; }

  void setParameters( const Teuchos::RCP<Teuchos::ParameterList> &params ) override;



  void reset( const ResetType type ) override {
    if ((type & Belos::Problem) && ! problem_.is_null ()) {
      problem_->setProblem ();
      poly_Op_ = Teuchos::null;
      poly_dim_ = 0;  // Rebuild the GMRES polynomial
    }
  }



  ReturnType solve() override;



  std::string description() const override;


private:

  // Linear problem.
  Teuchos::RCP<LinearProblem<ScalarType,MV,OP> > problem_;

  // Output manager.
  Teuchos::RCP<std::ostream> outputStream_;

  // Current parameter list.
  Teuchos::RCP<Teuchos::ParameterList> params_;
  Teuchos::RCP<Teuchos::ParameterList> outerParams_;

  // Default solver values.
  static constexpr int maxDegree_default_ = 25;
  static constexpr int verbosity_default_ = Belos::Errors;
  static constexpr const char * label_default_ = "Belos";
  static constexpr const char * outerSolverType_default_ = "";
  static constexpr const char * polyType_default_ = "Arnoldi";
  static constexpr const char * orthoType_default_ = "ICGS";
  static constexpr bool addRoots_default_ = true;
  static constexpr bool dampPoly_default_ = false;
  static constexpr bool randomRHS_default_ = true; 

  // Current solver values.
  MagnitudeType polyTol_, achievedTol_;
  int maxDegree_, numIters_;
  int verbosity_;
  bool hasOuterSolver_;
  bool randomRHS_;
  bool damp_;
  bool addRoots_;
  std::string polyType_;
  std::string outerSolverType_;
  std::string orthoType_;

  // Polynomial storage
  int poly_dim_;
  Teuchos::RCP<gmres_poly_t> poly_Op_;

  // Timers.
  std::string label_;
  Teuchos::RCP<Teuchos::Time> timerPoly_;

  // Internal state variables.
  bool isSet_;
  bool loaDetected_;

  mutable Teuchos::RCP<const Teuchos::ParameterList> validPL_;
};


template<class ScalarType, class MV, class OP>
GmresPolySolMgr<ScalarType,MV,OP>::GmresPolySolMgr () :
  outputStream_ (Teuchos::rcpFromRef(std::cout)),
  polyTol_ (DefaultSolverParameters::polyTol),
  achievedTol_(MTS::zero()),
  maxDegree_ (maxDegree_default_),
  numIters_ (0),
  verbosity_ (verbosity_default_),
  hasOuterSolver_ (false),
  randomRHS_ (randomRHS_default_),
  damp_ (dampPoly_default_),
  addRoots_ (addRoots_default_),
  polyType_ (polyType_default_),
  outerSolverType_ (outerSolverType_default_),
  orthoType_ (orthoType_default_),
  poly_dim_ (0),
  label_ (label_default_),
  isSet_ (false),
  loaDetected_ (false)
{}


template<class ScalarType, class MV, class OP>
GmresPolySolMgr<ScalarType,MV,OP>::
GmresPolySolMgr (const Teuchos::RCP<LinearProblem<ScalarType,MV,OP> > &problem,
                 const Teuchos::RCP<Teuchos::ParameterList> &pl) :
  problem_ (problem),
  outputStream_ (Teuchos::rcpFromRef(std::cout)),
  polyTol_ (DefaultSolverParameters::polyTol),
  maxDegree_ (maxDegree_default_),
  numIters_ (0),
  verbosity_ (verbosity_default_),
  hasOuterSolver_ (false),
  randomRHS_ (randomRHS_default_),
  damp_ (dampPoly_default_),
  addRoots_ (addRoots_default_),
  polyType_ (polyType_default_),
  outerSolverType_ (outerSolverType_default_),
  orthoType_ (orthoType_default_),
  poly_dim_ (0),
  label_ (label_default_),
  isSet_ (false),
  loaDetected_ (false)
{
  TEUCHOS_TEST_FOR_EXCEPTION(
    problem_.is_null (), std::invalid_argument,
    "Belos::GmresPolySolMgr: The given linear problem is null.  "
    "Please call this constructor with a nonnull LinearProblem argument, "
    "or call the constructor that does not take a LinearProblem.");

  // If the input parameter list is null, then the parameters take
  // default values.
  if (! pl.is_null ()) {
    setParameters (pl);
  }
}


template<class ScalarType, class MV, class OP>
Teuchos::RCP<const Teuchos::ParameterList>
GmresPolySolMgr<ScalarType,MV,OP>::getValidParameters() const
{
  if (validPL_.is_null ()) {
    Teuchos::RCP<Teuchos::ParameterList> pl = Teuchos::parameterList ();

    // The static_cast is to resolve an issue with older clang versions which
    // would cause the constexpr to link fail. With c++17 the problem is resolved.
    pl->set("Polynomial Type", static_cast<const char *>(polyType_default_),
      "The type of GMRES polynomial that is used as a preconditioner: Roots, Arnoldi, or Gmres.");
    pl->set("Polynomial Tolerance", static_cast<MagnitudeType>(DefaultSolverParameters::polyTol),
      "The relative residual tolerance that used to construct the GMRES polynomial.");
    pl->set("Maximum Degree", static_cast<int>(maxDegree_default_),
      "The maximum degree allowed for any GMRES polynomial.");
    pl->set("Outer Solver", static_cast<const char *>(outerSolverType_default_),
      "The outer solver that this polynomial is used to precondition.");
    pl->set("Outer Solver Params", Teuchos::ParameterList(),
      "Parameter list for the outer solver.");
    pl->set("Verbosity", static_cast<int>(verbosity_default_),
      "What type(s) of solver information should be outputted\n"
      "to the output stream.");
    pl->set("Output Stream", Teuchos::rcpFromRef(std::cout),
      "A reference-counted pointer to the output stream where all\n"
      "solver output is sent.");
    pl->set("Timer Label", static_cast<const char *>(label_default_),
      "The string to use as a prefix for the timer labels.");
    pl->set("Orthogonalization", static_cast<const char *>(orthoType_default_),
      "The type of orthogonalization to use to generate polynomial: DGKS, ICGS, or IMGS.");
    pl->set("Random RHS", static_cast<bool>(randomRHS_default_),
      "Add roots to polynomial for stability.");
    pl->set("Add Roots", static_cast<bool>(addRoots_default_),
      "Add roots to polynomial for stability.");
    pl->set("Damp Poly", static_cast<bool>(dampPoly_default_),
      "Damp polynomial for ill-conditioned problems.");
    validPL_ = pl;
  }
  return validPL_;
}


template<class ScalarType, class MV, class OP>
void GmresPolySolMgr<ScalarType,MV,OP>::
setParameters (const Teuchos::RCP<Teuchos::ParameterList>& params)
{
  // Create the internal parameter list if ones doesn't already exist.
  if (params_.is_null ()) {
    params_ = Teuchos::parameterList (*getValidParameters ());
  }
  else {
    params->validateParameters (*getValidParameters (),0);
  }

  // Check which Gmres polynomial to use
  if (params->isParameter("Polynomial Type")) {
    polyType_ = params->get("Polynomial Type", polyType_default_);
  }

  // Update the outer solver in our list.
  params_->set("Polynomial Type", polyType_);

  // Check if there is an outer solver for this Gmres Polynomial
  if (params->isParameter("Outer Solver")) {
    outerSolverType_ = params->get("Outer Solver", outerSolverType_default_);
  }

  // Update the outer solver in our list.
  params_->set("Outer Solver", outerSolverType_);

  // Check if there is a parameter list for the outer solver
  if (params->isSublist("Outer Solver Params")) {
    outerParams_ = Teuchos::parameterList( params->get<Teuchos::ParameterList>("Outer Solver Params") );
  }   

  // Check for maximum polynomial degree
  if (params->isParameter("Maximum Degree")) {
    maxDegree_ = params->get("Maximum Degree",maxDegree_default_);
  }

  // Update parameter in our list.
  params_->set("Maximum Degree", maxDegree_);

  // Check to see if the timer label changed.
  if (params->isParameter("Timer Label")) {
    std::string tempLabel = params->get("Timer Label", label_default_);

    // Update parameter in our list and solver timer
    if (tempLabel != label_) {
      label_ = tempLabel;
#ifdef BELOS_TEUCHOS_TIME_MONITOR
      std::string polyLabel = label_ + ": GmresPolyOp creation time";
      timerPoly_ = Teuchos::TimeMonitor::getNewCounter(polyLabel);
#endif
    }
  }

  // Update timer label
  params_->set("Timer Label", label_);

  // Check if the orthogonalization changed.
  if (params->isParameter("Orthogonalization")) {
    std::string tempOrthoType = params->get("Orthogonalization",orthoType_default_);
    OrthoManagerFactory<ScalarType, MV, OP> factory;
    // Ensure that the specified orthogonalization type is valid.
    if (! factory.isValidName (tempOrthoType)) {
      std::ostringstream os;
      os << "Belos::GCRODRSolMgr: Invalid orthogonalization name \""
         << tempOrthoType << "\".  The following are valid options "
         << "for the \"Orthogonalization\" name parameter: ";
      factory.printValidNames (os);
      throw std::invalid_argument (os.str());
    }
    if (tempOrthoType != orthoType_) {
      orthoType_ = tempOrthoType;
    }
  }

  params_->set("Orthogonalization", orthoType_);

  // Check for a change in verbosity level
  if (params->isParameter("Verbosity")) {
    if (Teuchos::isParameterType<int>(*params,"Verbosity")) {
      verbosity_ = params->get("Verbosity", verbosity_default_);
    } else {
      verbosity_ = (int)Teuchos::getParameter<Belos::MsgType>(*params,"Verbosity");
    }
  }

  // Update parameter in our list.
  params_->set("Verbosity", verbosity_);

  // output stream
  if (params->isParameter("Output Stream")) {
    outputStream_ = Teuchos::getParameter<Teuchos::RCP<std::ostream> >(*params,"Output Stream");
  }

  // Update parameter in our list.
  params_->set("Output Stream", outputStream_);

  // Convergence
  // Check for polynomial convergence tolerance
  if (params->isParameter("Polynomial Tolerance")) {
    if (params->isType<MagnitudeType> ("Polynomial Tolerance")) {
      polyTol_ = params->get ("Polynomial Tolerance",
                              static_cast<MagnitudeType> (DefaultSolverParameters::polyTol));
    }
    else {
      polyTol_ = params->get ("Polynomial Tolerance", DefaultSolverParameters::polyTol);
    }
  }

  // Update parameter in our list and residual tests.
  params_->set("Polynomial Tolerance", polyTol_);

  // Check for maximum polynomial degree
  if (params->isParameter("Random RHS")) {
    randomRHS_ = params->get("Random RHS",randomRHS_default_);
  }

  // Update parameter in our list.
  params_->set("Random RHS", randomRHS_);
  
  
  // Check for polynomial damping
  if (params->isParameter("Damped Poly")) {
    damp_ = params->get("Damped Poly",dampPoly_default_);
  }
  // Update parameter in our list.
  params_->set("Damped Poly", damp_);

  // Check: Should we add roots for stability if needed?
  if (params->isParameter("Add Roots")) {
    addRoots_ = params->get("Add Roots",addRoots_default_);
  }

  // Update parameter in our list.
  params_->set("Add Roots", addRoots_);

  // Create the timers if we need to.
#ifdef BELOS_TEUCHOS_TIME_MONITOR
  if (timerPoly_ == Teuchos::null) {
    std::string polyLabel = label_ + ": GmresPolyOp creation time";
    timerPoly_ = Teuchos::TimeMonitor::getNewCounter(polyLabel);
  }
#endif

  // Check if we are going to perform an outer solve.
  if (outerSolverType_ != "") { 
    hasOuterSolver_ = true;
  }

  // Inform the solver manager that the current parameters were set.
  isSet_ = true;
}


template<class ScalarType, class MV, class OP>
ReturnType GmresPolySolMgr<ScalarType,MV,OP>::solve ()
{
  using Teuchos::RCP;
  using Teuchos::rcp;
  using Teuchos::rcp_const_cast;

  // Assume convergence is achieved if user does not require strict convergence.
  ReturnType ret = Belos::Converged;

  // Set the current parameters if they were not set before.  NOTE:
  // This may occur if the user generated the solver manager with the
  // default constructor and then didn't set any parameters using
  // setParameters().
  if (! isSet_) {
    setParameters (Teuchos::parameterList (*getValidParameters ()));
  }

  TEUCHOS_TEST_FOR_EXCEPTION(
    problem_.is_null (), GmresPolySolMgrLinearProblemFailure,
    "Belos::GmresPolySolMgr::solve: The linear problem has not been set yet, "
    "or was set to null.  Please call setProblem() with a nonnull input before "
    "calling solve().");

  TEUCHOS_TEST_FOR_EXCEPTION(
    ! problem_->isProblemSet (), GmresPolySolMgrLinearProblemFailure,
    "Belos::GmresPolySolMgr::solve: The linear problem is not ready.  Please "
    "call setProblem() on the LinearProblem object before calling solve().");

  // If the GMRES polynomial has not been constructed for this
  // (nmatrix, preconditioner) pair, generate it.
  if (!poly_dim_ && maxDegree_) {
#ifdef BELOS_TEUCHOS_TIME_MONITOR
    Teuchos::TimeMonitor slvtimer(*timerPoly_);
#endif
    poly_Op_ = Teuchos::rcp( new gmres_poly_t( problem_, params_ ) );
    poly_dim_ = poly_Op_->polyDegree();

    TEUCHOS_TEST_FOR_EXCEPTION( !poly_dim_, GmresPolySolMgrPolynomialFailure,
      "Belos::GmresPolyOp: Failed to generate polynomial that satisfied requirements.");
  }


  // Solve the linear system using the polynomial
  if (hasOuterSolver_  && maxDegree_) {

    // Then the polynomial will be used as an operator for an outer solver.
    // Use outer solver parameter list passed in a sublist.
    Belos::GenericSolverFactory<ScalarType, MultiVec<ScalarType>, Operator<ScalarType> > factory;
    RCP<SolverManager<ScalarType, MultiVec<ScalarType>, Operator<ScalarType> > > solver = factory.create( outerSolverType_, outerParams_ );
    TEUCHOS_TEST_FOR_EXCEPTION( solver == Teuchos::null, std::invalid_argument,
      "Belos::GmresPolySolMgr::solve(): Selected solver is not valid.");

    // Create a copy of the linear problem that uses the polynomial as a preconditioner.
    // The original initial solution and right-hand side are thinly wrapped in the gmres_poly_mv_t
    RCP<gmres_poly_mv_t> new_lhs = rcp( new gmres_poly_mv_t( problem_->getLHS() ) );
    RCP<gmres_poly_mv_t> new_rhs = rcp( new gmres_poly_mv_t( rcp_const_cast<MV>( problem_->getRHS() ) ) );
    RCP<gmres_poly_t> A = rcp( new gmres_poly_t( problem_ ) );  // This just performs problem_->applyOp
    RCP<LinearProblem<ScalarType,MultiVec<ScalarType>,Operator<ScalarType> > > newProblem =
      rcp( new LinearProblem<ScalarType,MultiVec<ScalarType>,Operator<ScalarType> >( A, new_lhs, new_rhs ) );
    std::string solverLabel = label_ + ": Hybrid Gmres";
    newProblem->setLabel(solverLabel); 

    // If the preconditioner is left preconditioner, use Gmres poly as a left preconditioner.
    if (problem_->getLeftPrec() != Teuchos::null)
      newProblem->setLeftPrec( poly_Op_ );
    else 
      newProblem->setRightPrec( poly_Op_ );
    // Set the initial residual vector, if it has already been set in the original problem.
    // Don't set the preconditioned residual vector, because it is not the GmresPoly preconditioned residual vector.
    if (problem_->getInitResVec() != Teuchos::null)
      newProblem->setInitResVec( rcp( new gmres_poly_mv_t( rcp_const_cast<MV>( problem_->getInitResVec() ) ) ) );
    newProblem->setProblem();

    solver->setProblem( newProblem );
    
    ret = solver->solve();
    numIters_ = solver->getNumIters();
    loaDetected_ = solver->isLOADetected();
    achievedTol_ = solver->achievedTol();

  } // if (hasOuterSolver_ && maxDegree_)
  else if (hasOuterSolver_) {

    // There is no polynomial, just create the outer solver with the outerSolverType_ and outerParams_.
    Belos::SolverFactory<ScalarType, MV, OP> factory;
    RCP<SolverManager<ScalarType, MV, OP> > solver = factory.create( outerSolverType_, outerParams_ );
    TEUCHOS_TEST_FOR_EXCEPTION( solver == Teuchos::null, std::invalid_argument,
      "Belos::GmresPolySolMgr::solve(): Selected solver is not valid.");

    solver->setProblem( problem_ );
    
    ret = solver->solve();
    numIters_ = solver->getNumIters();
    loaDetected_ = solver->isLOADetected();
    achievedTol_ = solver->achievedTol();

  }
  else if (maxDegree_) {

    // Apply the polynomial to the current linear system
    poly_Op_->ApplyPoly( *problem_->getRHS(), *problem_->getLHS() );
    achievedTol_ = MTS::one();

  }

  return ret;
}


template<class ScalarType, class MV, class OP>
std::string GmresPolySolMgr<ScalarType,MV,OP>::description () const
{
  std::ostringstream out;

  out << "\"Belos::GmresPolySolMgr\": {"
      << "ScalarType: " << Teuchos::TypeNameTraits<ScalarType>::name ()
      << ", Poly Degree: " << poly_dim_
      << ", Poly Max Degree: " << maxDegree_
      << ", Poly Tol: " << polyTol_;
  out << "}";
  return out.str ();
}

} // namespace Belos

#endif // BELOS_GMRES_POLY_SOLMGR_HPP