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>
 
namespace dftefe
{
  namespace linearAlgebra
  {
    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,
        MultiVector<ValueTypeOperand, memorySpace> &eigenSubspaceGuess,
        const size_type                             eigenVectorBlockSize = 0);
 
      ~ChebyshevFilteredEigenSolver() = default;
 
      void
      reinit(const double wantedSpectrumLowerBound,
             const double wantedSpectrumUpperBound,
             const double unWantedSpectrumUpperBound,
             const double polynomialDegree,
             const double illConditionTolerance,
             MultiVector<ValueTypeOperand, memorySpace> &eigenSubspaceGuess,
             const size_type                             eigenVectorBlockSize);
 
      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();
 
    private:
      double                                      d_wantedSpectrumLowerBound;
      double                                      d_wantedSpectrumUpperBound;
      double                                      d_unWantedSpectrumUpperBound;
      double                                      d_polynomialDegree;
      double                                      d_illConditionTolerance;
      MultiVector<ValueTypeOperand, memorySpace> *d_eigenSubspaceGuess;
      size_type                                   d_eigenVectorBlockSize;
 
      std::shared_ptr<MultiVector<ValueType, memorySpace>>
        d_filteredSubspaceOrtho;
      std::shared_ptr<MultiVector<ValueType, memorySpace>> d_filteredSubspace;
 
      std::shared_ptr<
        RayleighRitzEigenSolver<ValueTypeOperator, ValueType, memorySpace>>
        d_rr;
 
    }; // end of class ChebyshevFilteredEigenSolver
  }    // end of namespace linearAlgebra
} // end of namespace dftefe
#include <linearAlgebra/ChebyshevFilteredEigenSolver.t.cpp>
#endif // dftefeChebyshevFilteredEigenSolver_h