eigen_chebyshev.F90

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!! Copyright (C) 2023. A Buccheri.
!!
!! This Source Code Form is subject to the terms of the Mozilla Public
!! License, v. 2.0. If a copy of the MPL was not distributed with this
!! file, You can obtain one at https://mozilla.org/MPL/2.0/.
!!
#include "global.h"
 
module eigen_chebyshev_oct_m
  use batch_oct_m
  use batch_ops_oct_m
  use comm_oct_m
  use debug_oct_m
  use chebyshev_filter_bounds_oct_m
  use chebyshev_filter_oracle_oct_m
  use global_oct_m
  use hamiltonian_elec_oct_m
  use hamiltonian_elec_base_oct_m
  use, intrinsic :: iso_fortran_env
  use lalg_adv_oct_m
  use loct_oct_m
  use mesh_oct_m
  use mesh_batch_oct_m
  use mesh_function_oct_m
  use messages_oct_m
  use mpi_oct_m
  use namespace_oct_m
  use profiling_oct_m
  use states_elec_oct_m
  use states_elec_calc_oct_m
  use subspace_oct_m
  use wfs_elec_oct_m
 
  implicit none
  private
 
  type eigen_chebyshev_t
    integer  :: n_lanczos
    integer :: degree
    real(real64) :: bound_mixing
    !                                  !< for approximation of the spectral filter''s lower bound:
    !                                  !< lower_bound = bm * min(e_approx) + (bm - 1) * max(eig_approx)
    !                                  !< such that bm = 0 => lower_bound = max(eig_approx)
    !                                  !<           bm = 1 => lower_bound = min(eig_approx)
    integer :: n_iter
    logical :: optimize_degree
 
    real(real64),    allocatable :: dlanczos_state(:,:,:)
    !                                                        this converges faster than a random state at each step
    complex(real64), allocatable :: zlanczos_state(:,:,:)
    logical :: known_lower_bound = .false.
  contains
    final :: finalize
  end type eigen_chebyshev_t
 
  type(eigen_chebyshev_t) :: default_chebyshev_params = eigen_chebyshev_t(-1, 15, m_half, 5, .true.)
 
  type batch_pointer_t
    private
    type(wfs_elec_t), pointer :: batch
  end type batch_pointer_t
 
  public :: &
    eigen_chebyshev_t, &
    default_chebyshev_params, &
    dchebyshev_filter_solver, zchebyshev_filter_solver, &
    dchebyshev_filter, &
    zchebyshev_filter
 
contains
 
  subroutine finalize(this)
    type(eigen_chebyshev_t), intent(inout) :: this
 
    safe_deallocate_a(this%dlanczos_state)
    safe_deallocate_a(this%zlanczos_state)
 
  end subroutine finalize
 
 
#include "real.F90"
#include "eigen_chebyshev_inc.F90"
#include "undef.F90"
 
#include "complex.F90"
#include "eigen_chebyshev_inc.F90"
#include "undef.F90"
 
end module eigen_chebyshev_oct_m