Ifpack2_ILUT_decl.hpp

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// @HEADER
// *****************************************************************************
//       Ifpack2: Templated Object-Oriented Algebraic Preconditioner Package
//
// Copyright 2009 NTESS and the Ifpack2 contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER


#ifndef IFPACK2_ILUT_DECL_HPP
#define IFPACK2_ILUT_DECL_HPP

#include "KokkosSparse_par_ilut.hpp"

#include "Ifpack2_Preconditioner.hpp"
#include "Ifpack2_Details_CanChangeMatrix.hpp"
#include "Tpetra_CrsMatrix_decl.hpp"
#include "Ifpack2_LocalSparseTriangularSolver_decl.hpp"

#include <string>
#include <sstream>
#include <iostream>
#include <cmath>
#include <type_traits>

namespace Teuchos {
class ParameterList;  // forward declaration
}

namespace Ifpack2 {

template <class MatrixType>
class ILUT : virtual public Ifpack2::Preconditioner<typename MatrixType::scalar_type,
                                                    typename MatrixType::local_ordinal_type,
                                                    typename MatrixType::global_ordinal_type,
                                                    typename MatrixType::node_type>,
             virtual public Ifpack2::Details::CanChangeMatrix<Tpetra::RowMatrix<typename MatrixType::scalar_type,
                                                                                typename MatrixType::local_ordinal_type,
                                                                                typename MatrixType::global_ordinal_type,
                                                                                typename MatrixType::node_type> > {
 public:


  typedef typename MatrixType::scalar_type scalar_type;

  typedef typename MatrixType::local_ordinal_type local_ordinal_type;

  typedef typename MatrixType::global_ordinal_type global_ordinal_type;

  typedef typename MatrixType::node_type node_type;

  typedef typename Teuchos::ScalarTraits<scalar_type>::magnitudeType magnitude_type;

  typedef Tpetra::RowMatrix<scalar_type,
                            local_ordinal_type,
                            global_ordinal_type,
                            node_type>
      row_matrix_type;

  typedef typename row_matrix_type::global_inds_host_view_type global_inds_host_view_type;
  typedef typename row_matrix_type::local_inds_host_view_type local_inds_host_view_type;
  typedef typename row_matrix_type::values_host_view_type values_host_view_type;

  typedef typename row_matrix_type::nonconst_global_inds_host_view_type nonconst_global_inds_host_view_type;
  typedef typename row_matrix_type::nonconst_local_inds_host_view_type nonconst_local_inds_host_view_type;
  typedef typename row_matrix_type::nonconst_values_host_view_type nonconst_values_host_view_type;

  static_assert(std::is_same<MatrixType, row_matrix_type>::value, "Ifpack2::ILUT: The template parameter MatrixType must be a Tpetra::RowMatrix specialization.  Please don't use Tpetra::CrsMatrix (a subclass of Tpetra::RowMatrix) here anymore.  The constructor can take either a RowMatrix or a CrsMatrix just fine.");

  typedef Tpetra::CrsMatrix<scalar_type,
                            local_ordinal_type,
                            global_ordinal_type,
                            node_type>
      crs_matrix_type;

  typedef typename crs_matrix_type::local_matrix_device_type local_matrix_device_type;
  typedef typename local_matrix_device_type::StaticCrsGraphType::row_map_type lno_row_view_t;
  typedef Tpetra::CrsGraph<local_ordinal_type, global_ordinal_type, node_type> crs_graph_type;
  typedef typename crs_graph_type::local_graph_device_type local_graph_device_type;
  typedef typename local_graph_device_type::array_layout array_layout;
  typedef typename local_graph_device_type::device_type device_type;
  typedef typename local_graph_device_type::size_type usize_type;
  // KokkosKernels requires unsigned
  // typedef typename Kokkos::View<size_type*, array_layout, device_type> lno_row_view_t;
  typedef typename Kokkos::View<usize_type*, array_layout, device_type> lno_urow_view_t;
  typedef typename local_matrix_device_type::StaticCrsGraphType::entries_type lno_nonzero_view_t;
  // typedef typename Kokkos::View<lno_nonzero_view_t*, array_layout, device_type> static_graph_entries_t;
  typedef typename Kokkos::View<typename local_matrix_device_type::non_const_ordinal_type*, array_layout, device_type> static_graph_entries_t;
  typedef typename local_matrix_device_type::values_type scalar_nonzero_view_t;
  // typedef typename Kokkos::View<scalar_nonzero_view_t*, array_layout, device_type> local_matrix_values_t;
  typedef typename Kokkos::View<typename local_matrix_device_type::non_const_value_type*, array_layout, device_type> local_matrix_values_t;
  typedef typename local_matrix_device_type::StaticCrsGraphType::device_type::memory_space TemporaryMemorySpace;
  typedef typename local_matrix_device_type::StaticCrsGraphType::device_type::memory_space PersistentMemorySpace;
  typedef typename local_matrix_device_type::StaticCrsGraphType::device_type::execution_space HandleExecSpace;
  typedef typename KokkosKernels::Experimental::KokkosKernelsHandle<typename lno_row_view_t::const_value_type, typename lno_nonzero_view_t::const_value_type, typename scalar_nonzero_view_t::value_type,
                                                                    HandleExecSpace, TemporaryMemorySpace, PersistentMemorySpace>
      kk_handle_type;

  typedef Tpetra::Map<local_ordinal_type,
                      global_ordinal_type,
                      node_type>
      map_type;


  explicit ILUT(const Teuchos::RCP<const row_matrix_type>& A);

  virtual ~ILUT() = default;



  void setParameters(const Teuchos::ParameterList& params);

  void initialize();

  inline bool isInitialized() const {
    return IsInitialized_;
  }


  void compute();

  inline bool isComputed() const {
    return IsComputed_;
  }



  virtual void
  setMatrix(const Teuchos::RCP<const row_matrix_type>& A);



  void
  apply(const Tpetra::MultiVector<scalar_type, local_ordinal_type, global_ordinal_type, node_type>& X,
        Tpetra::MultiVector<scalar_type, local_ordinal_type, global_ordinal_type, node_type>& Y,
        Teuchos::ETransp mode = Teuchos::NO_TRANS,
        scalar_type alpha     = Teuchos::ScalarTraits<scalar_type>::one(),
        scalar_type beta      = Teuchos::ScalarTraits<scalar_type>::zero()) const;

  Teuchos::RCP<const map_type> getDomainMap() const;

  Teuchos::RCP<const map_type> getRangeMap() const;

  bool hasTransposeApply() const;



  Teuchos::RCP<const Teuchos::Comm<int> > getComm() const;

  Teuchos::RCP<const row_matrix_type> getMatrix() const;

  Teuchos::RCP<const crs_matrix_type> getL() const { return L_; }

  Teuchos::RCP<const crs_matrix_type> getU() const { return U_; }

  int getNumInitialize() const;

  int getNumCompute() const;

  int getNumApply() const;

  double getInitializeTime() const;

  double getComputeTime() const;

  double getApplyTime() const;

  size_t getNodeSmootherComplexity() const;

  inline double getLevelOfFill() const {
    return LevelOfFill_;
  }

  inline magnitude_type getAbsoluteThreshold() const {
    return (Athresh_);
  }

  inline magnitude_type getRelativeThreshold() const {
    return (Rthresh_);
  }

  inline magnitude_type getRelaxValue() const {
    return (RelaxValue_);
  }

  inline magnitude_type getDropTolerance() const {
    return (DropTolerance_);
  }

  global_size_t getGlobalNumEntries() const;

  size_t getLocalNumEntries() const;



  std::string description() const;

  void describe(Teuchos::FancyOStream& out, const Teuchos::EVerbosityLevel verbLevel = Teuchos::Describable::verbLevel_default) const;


 private:
  typedef Tpetra::MultiVector<scalar_type, local_ordinal_type, global_ordinal_type, node_type> MV;
  typedef Teuchos::ScalarTraits<scalar_type> STS;
  typedef Teuchos::ScalarTraits<magnitude_type> STM;
  typedef typename Teuchos::Array<local_ordinal_type>::size_type size_type;

  ILUT(const ILUT<MatrixType>& RHS);

  void allocateSolvers();

  ILUT<MatrixType>& operator=(const ILUT<MatrixType>& RHS);

  static Teuchos::RCP<const row_matrix_type>
  makeLocalFilter(const Teuchos::RCP<const row_matrix_type>& A);

  // \name The matrix and its incomplete LU factors

  Teuchos::RCP<const row_matrix_type> A_;
  Teuchos::RCP<const row_matrix_type> A_local_;
  lno_row_view_t A_local_rowmap_;
  lno_nonzero_view_t A_local_entries_;
  scalar_nonzero_view_t A_local_values_;
  Teuchos::RCP<crs_matrix_type> L_;
  lno_urow_view_t L_rowmap_;
  lno_urow_view_t U_rowmap_;
  lno_urow_view_t L_rowmap_orig_;
  lno_urow_view_t U_rowmap_orig_;
  Teuchos::RCP<LocalSparseTriangularSolver<row_matrix_type> > L_solver_;
  Teuchos::RCP<crs_matrix_type> U_;
  Teuchos::RCP<LocalSparseTriangularSolver<row_matrix_type> > U_solver_;

  // \name Parameters (set by setParameters())

  magnitude_type Athresh_;     
  magnitude_type Rthresh_;     
  magnitude_type RelaxValue_;  
  double LevelOfFill_;         
  magnitude_type DropTolerance_;
  // See https://kokkos-kernels.readthedocs.io/en/latest/developer/apidocs/sparse.html#par-ilut
  // for more information on the following options.
  mutable struct par_ilut_option_struct {
    int max_iter;
    magnitude_type residual_norm_delta_stop;
    int team_size;
    int vector_size;
    double fill_in_limit;  // Note: par_ilut declares this as float
    bool verbose;
  } par_ilut_options_;

  // \name Other internal data

  double InitializeTime_;
  double ComputeTime_;
  mutable double ApplyTime_;
  int NumInitialize_;
  int NumCompute_;
  mutable int NumApply_;
  bool IsInitialized_;
  bool IsComputed_;

  bool useKokkosKernelsParILUT_;
  Teuchos::RCP<kk_handle_type> KernelHandle_;

};  // class ILUT

}  // namespace Ifpack2

#endif /* IFPACK2_ILUT_HPP */