ChebyshevFilteredEigenSolver.h

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 * Copyright (c) 2021.                                                        *
 * The Regents of the University of Michigan and DFT-EFE developers.          *
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 *   See the Lesser GNU General Public License for more details.              *
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/*
 * @author Avirup Sircar
 */
 
#ifndef dftefeChebyshevFilteredEigenSolver_h
#define dftefeChebyshevFilteredEigenSolver_h
 
#include <utils/MemorySpaceType.h>
#include <linearAlgebra/BlasLapackTypedef.h>
#include <linearAlgebra/LinAlgOpContext.h>
#include <linearAlgebra/Vector.h>
#include <linearAlgebra/MultiVector.h>
#include <linearAlgebra/OperatorContext.h>
#include <linearAlgebra/HermitianIterativeEigenSolver.h>
#include <linearAlgebra/RayleighRitzEigenSolver.h>
#include <linearAlgebra/ChebyshevFilter.h>
#include <memory>
#include <utils/Profiler.h>
#include <linearAlgebra/MultivectorScratch.h>
 
namespace dftefe
{
  namespace linearAlgebra
  {
    enum class OrthogonalizationType
    {
      CHOLESKY_GRAMSCHMIDT,
      MULTIPASS_CGS,
      MULTIPASS_LOWDIN,
    };
 
    template <typename ValueTypeOperator,
              typename ValueTypeOperand,
              utils::MemorySpace memorySpace>
    class ChebyshevFilteredEigenSolver
      : public HermitianIterativeEigenSolver<ValueTypeOperator,
                                             ValueTypeOperand,
                                             memorySpace>
    {
    public:
      using ValueType =
        blasLapack::scalar_type<ValueTypeOperator, ValueTypeOperand>;
      using RealType = blasLapack::real_type<ValueType>;
      using OpContext =
        typename HermitianIterativeEigenSolver<ValueTypeOperator,
                                               ValueTypeOperand,
                                               memorySpace>::OpContext;
 
    public:
      ChebyshevFilteredEigenSolver(
        const double wantedSpectrumLowerBound,
        const double wantedSpectrumUpperBound,
        const double unWantedSpectrumUpperBound,
        const double polynomialDegree,
        const double illConditionTolerance,
        std::shared_ptr<const utils::mpi::MPIPatternP2P<memorySpace>>
                                                      mpiPatternP2P,
        std::shared_ptr<LinAlgOpContext<memorySpace>> linAlgOpContext,
        const ElpaScalapackManager &                  elpaScala,
        bool                  isResidualChebyshevFilter = true,
        const size_type       eigenVectorBatchSize      = 0,
        bool                  isGHEP                    = true,
        OrthogonalizationType orthoType =
          OrthogonalizationType::CHOLESKY_GRAMSCHMIDT,
        bool storeIntermediateSubspaces = false,
        std::shared_ptr<MultivectorScratch<ValueType, memorySpace>> scratch =
          nullptr);
 
      ~ChebyshevFilteredEigenSolver() = default;
 
      void
      reinit(const double wantedSpectrumLowerBound,
             const double wantedSpectrumUpperBound,
             const double unWantedSpectrumUpperBound,
             const double polynomialDegree,
             const double illConditionTolerance,
             std::shared_ptr<const utils::mpi::MPIPatternP2P<memorySpace>>
                                                           mpiPatternP2P,
             std::shared_ptr<LinAlgOpContext<memorySpace>> linAlgOpContext);
 
      EigenSolverError
      solve(const OpContext &                    A,
            std::vector<RealType> &              eigenValues,
            MultiVector<ValueType, memorySpace> &eigenVectors,
            bool                                 computeEigenVectors = false,
            const OpContext &B = IdentityOperatorContext<ValueTypeOperator,
                                                         ValueTypeOperand,
                                                         memorySpace>(),
            const OpContext &BInv =
              IdentityOperatorContext<ValueTypeOperator,
                                      ValueTypeOperand,
                                      memorySpace>()) override;
 
      MultiVector<ValueType, memorySpace> &
      getFilteredSubspace();
 
      MultiVector<ValueType, memorySpace> &
      getOrthogonalizedFilteredSubspace();
 
      void
      printTotalInScopeTimings();
 
    private:
      double                                      d_wantedSpectrumLowerBound;
      double                                      d_wantedSpectrumUpperBound;
      double                                      d_unWantedSpectrumUpperBound;
      double                                      d_polynomialDegree;
      double                                      d_illConditionTolerance;
      MultiVector<ValueTypeOperand, memorySpace> *d_eigenSubspaceGuess;
      const size_type                             d_eigenVecBatchSize;
      const bool                                  d_storeIntermediateSubspaces;
 
      std::shared_ptr<MultiVector<ValueType, memorySpace>> d_filteredSubspace,
        d_filteredSubspaceOrtho;
 
      std::shared_ptr<MultiVector<ValueType, memorySpace>> d_XinBatchSmall,
        d_XinBatch, d_XoutBatchSmall, d_XoutBatch;
 
      std::shared_ptr<MultiVector<ValueType, memorySpace>> d_chfsiScratch1,
        d_chfsiScratch2, d_chfsiResidualScratch1, d_chfsiResidualScratch2;
      std::shared_ptr<MultiVector<ValueType, memorySpace>> d_chfsiScratch1Small,
        d_chfsiScratch2Small, d_chfsiResidualScratch1Small,
        d_chfsiResidualScratch2Small;
 
      std::shared_ptr<
        RayleighRitzEigenSolver<ValueTypeOperator, ValueType, memorySpace>>
        d_rr;
 
      std::shared_ptr<
        OrthonormalizationFunctions<ValueTypeOperator, ValueType, memorySpace>>
        d_ortho;
 
      utils::Profiler<memorySpace> d_p, d_pTotal;
      const bool                   d_isResidualChebyFilter;
      size_type                    d_batchSizeSmall;
 
      std::shared_ptr<const utils::mpi::MPIPatternP2P<memorySpace>>
                            d_mpiPatternP2P;
      bool                  d_printL2Norms;
      OrthogonalizationType d_orthoType;
 
      const ElpaScalapackManager *d_elpaScala;
 
      const bool d_isGHEP;
 
      std::shared_ptr<MultivectorScratch<ValueType, memorySpace>> d_scratch;
 
    }; // end of class ChebyshevFilteredEigenSolver
  }    // end of namespace linearAlgebra
} // end of namespace dftefe
#include <linearAlgebra/ChebyshevFilteredEigenSolver.t.cpp>
#endif // dftefeChebyshevFilteredEigenSolver_h