propagator_beeman.F90

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!! Copyright (C)  2020 N. Tancogne-Dejean
!!
!! This program is free software; you can redistribute it and/or modify
!! it under the terms of the GNU General Public License as published by
!! the Free Software Foundation; either version 2, or (at your option)
!! any later version.
!!
!! This program is distributed in the hope that it will be useful,
!! but WITHOUT ANY WARRANTY; without even the implied warranty of
!! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
!! GNU General Public License for more details.
!!
!! You should have received a copy of the GNU General Public License
!! along with this program; if not, write to the Free Software
!! Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
!! 02110-1301, USA.
!!
 
#include "global.h"
 
module propagator_beeman_oct_m
  use, intrinsic :: iso_fortran_env
  use algorithm_oct_m
  use debug_oct_m
  use global_oct_m
  use propagator_oct_m
 
  implicit none
 
  private
  public ::                            &
    propagator_beeman_t
 
  type, extends(propagator_t) :: propagator_beeman_t
    private
  end type propagator_beeman_t
 
  interface propagator_beeman_t
    procedure propagator_beeman_constructor
  end interface propagator_beeman_t
 
  !# doc_start beeman_propagation_operations
  ! Specific beeman propagation operations identifiers
  character(len=ALGO_LABEL_LEN), public, parameter ::  &
    BEEMAN_START       = 'BEEMAN_START',               &
    beeman_finish      = 'BEEMAN_FINISH',              &
    beeman_compute_acc = 'BEEMAN_COMPUTE_ACC',         &
    beeman_predict_pos = 'BEEMAN_PREDICT_POS',         &
    beeman_predict_vel = 'BEEMAN_PREDICT_VEL',         &
    beeman_correct_pos = 'BEEMAN_CORRECT_POS',         &
    beeman_correct_vel = 'BEEMAN_CORRECT_VEL'
 
  ! Specific beeman propagation operations
  type(algorithmic_operation_t), public, parameter :: &
    OP_BEEMAN_START       = algorithmic_operation_t(beeman_start,       'Starting Beeman propagation'),               &
    op_beeman_finish      = algorithmic_operation_t(beeman_finish,      'Finishing Beeman propagation'),              &
    op_beeman_compute_acc = algorithmic_operation_t(beeman_compute_acc, 'Propagation step - Computing acceleration'), &
    op_beeman_predict_pos = algorithmic_operation_t(beeman_predict_pos, 'Prediction step  - Computing position'),     &
    op_beeman_predict_vel = algorithmic_operation_t(beeman_predict_vel, 'Prediction step  - Computing velocity'),     &
    op_beeman_correct_pos = algorithmic_operation_t(beeman_correct_pos, 'Correction step  - Computing position'),     &
    op_beeman_correct_vel = algorithmic_operation_t(beeman_correct_vel, 'Correction step  - Computing velocity')
  !# doc_end
 
contains
 
  ! ---------------------------------------------------------
  function propagator_beeman_constructor(dt, predictor_corrector) result(this)
    real(real64),        intent(in)    :: dt
    logical,             intent(in)    :: predictor_corrector
    type(propagator_beeman_t), pointer :: this
 
    push_sub(propagator_beeman_constructor)
 
    allocate(this)
 
    this%predictor_corrector = predictor_corrector
 
    this%start_operation = op_beeman_start
    this%final_operation = op_beeman_finish
 
    if (predictor_corrector) then
 
      call this%add_operation(op_store_current_status)
      call this%add_operation(op_beeman_predict_pos)
      call this%add_operation(op_update_couplings)
      call this%add_operation(op_start_scf_loop)
      call this%add_operation(op_update_interactions)
      call this%add_operation(op_beeman_compute_acc)
      call this%add_operation(op_beeman_correct_pos)
      call this%add_operation(op_beeman_correct_vel)
      call this%add_operation(op_end_scf_loop)
      call this%add_operation(op_iteration_done)
      call this%add_operation(op_rewind_algorithm)
 
      this%max_scf_count = 2 !From Wikipedia
      this%scf_tol = 1e-6_real64 !At the moment arbitrary
 
    else
 
      call this%add_operation(op_beeman_predict_pos)
      call this%add_operation(op_update_couplings)
      call this%add_operation(op_update_interactions)
      call this%add_operation(op_beeman_compute_acc)
      call this%add_operation(op_beeman_predict_vel)
      call this%add_operation(op_iteration_done)
      call this%add_operation(op_rewind_algorithm)
 
    end if
 
    ! Beeman has only one algorithmic step
    this%algo_steps = 1
 
    this%dt = dt
 
    pop_sub(propagator_beeman_constructor)
  end function propagator_beeman_constructor
 
end module propagator_beeman_oct_m
 
 
!! Local Variables:
!! mode: f90
!! coding: utf-8
!! End: