slepc.h

// Copyright (C) 2005-2018 Garth N. Wells
//
// This file is part of DOLFINx (https://www.fenicsproject.org)
//
// SPDX-License-Identifier:    LGPL-3.0-or-later
 
#pragma once
 
#ifdef HAS_SLEPC
 
#include <complex>
#include <dolfinx/common/MPI.h>
#include <petscmat.h>
#include <petscvec.h>
#include <slepceps.h>
#include <string>
#include <string_view>
 
namespace dolfinx::la
{

class SLEPcEigenSolver
{
public:
  explicit SLEPcEigenSolver(MPI_Comm comm);

  SLEPcEigenSolver(EPS eps, bool inc_ref_count);
 
  // Copy constructor (deleted)
  SLEPcEigenSolver(const SLEPcEigenSolver&) = delete;

  SLEPcEigenSolver(SLEPcEigenSolver&& solver) noexcept;

  ~SLEPcEigenSolver();
 
  // Assignment operator (deleted)
  SLEPcEigenSolver& operator=(const SLEPcEigenSolver&) = delete;

  SLEPcEigenSolver& operator=(SLEPcEigenSolver&& solver) noexcept;

  void set_operators(const Mat A, const Mat B);

  [[nodiscard(
      "check the converged reason - positive on convergence, negative on "
      "divergence")]] EPSConvergedReason
  solve();

  std::complex<PetscReal> get_eigenvalue(PetscInt i) const;

  void get_eigenpair(PetscScalar& lr, PetscScalar& lc, Vec r, Vec c,
                     PetscInt i) const;

  void set_options_prefix(std::string_view options_prefix);

  std::string get_options_prefix() const;

  void set_from_options() const;

  EPS eps() const;

  MPI_Comm comm() const;
 
private:
  // SLEPc solver pointer
  EPS _eps;
};
} // namespace dolfinx::la
#endif