propagator.F90

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!! Copyright (C)  2019 N. Tancogne-Dejean
!! Copyright (C)  2020 M. Oliveira
!!
!! 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_oct_m
  use algorithm_oct_m
  use clock_oct_m
  use debug_oct_m
  use global_oct_m
  use iteration_counter_oct_m
  use messages_oct_m
  use namespace_oct_m
  use system_oct_m
 
  implicit none
 
  private
  public ::                       &
    propagator_t
 
  type, extends(algorithm_t), abstract :: propagator_t
    private
    class(system_t), pointer, public :: system
 
    type(algorithm_iterator_t) :: scf_start
 
    real(real64), public :: dt
    real(real64), public :: final_time = m_zero                    
 
    ! Options related to predictor-corrector propagators
    logical, public :: inside_scf = .false.                 
    logical, public :: predictor_corrector = .false.
    integer, public :: scf_count
    integer, public :: max_scf_count
    integer, public :: accumulated_loop_ticks
    real(real64), public   :: scf_tol
  contains
    ! Below are the list of operations that needs to be implemented
    procedure :: do_operation => propagator_do_operation       
    procedure :: finished => propagator_finished               
    procedure :: init_iteration_counters => propagator_init_iteration_counters         
    procedure :: save_scf_start => propagator_save_scf_start   
    procedure :: rewind_scf_loop => propagator_rewind_scf_loop 
  end type propagator_t
 
  !# doc_start general_propagation_operations
  ! Known propagation operations
  character(len=ALGO_LABEL_LEN), public, parameter ::   &
    START_SCF_LOOP       = 'START_SCF_LOOP',            &
    end_scf_loop         = 'END_SCF_LOOP',              &
    store_current_status = 'STORE_CURRENT_STATUS'
 
  type(algorithmic_operation_t), public, parameter :: &
    OP_START_SCF_LOOP       = algorithmic_operation_t(start_scf_loop,       'Starting SCF loop'),         &
    op_end_scf_loop         = algorithmic_operation_t(end_scf_loop,         'End of SCF iteration'),      &
    op_store_current_status = algorithmic_operation_t(store_current_status, 'Store current status')
  !# doc_end
 
 
contains
 
  logical function propagator_do_operation(this, operation) result(done)
    class(propagator_t),           intent(inout) :: this
    type(algorithmic_operation_t), intent(in)    :: operation
 
    done = .true.
 
    select case (operation%id)
    case (update_interactions)
      ! Update the accumulated loop ticks before executing this generic operation
      this%accumulated_loop_ticks = this%accumulated_loop_ticks + 1
      done = .false.
 
    case (start_scf_loop)
      assert(this%predictor_corrector)
 
      call this%save_scf_start()
      this%inside_scf = .true.
      this%accumulated_loop_ticks = 0
 
      if (debug%info) then
        write(message(1), '(a,i3,a)') "Debug: -- SCF iter ", this%scf_count, " for '" + trim(this%system%namespace%get()) + "'"
        call messages_info(1, namespace=this%system%namespace)
      end if
 
    case (end_scf_loop)
      ! Here we first check if we did the maximum number of steps.
      ! Otherwise, we need check the tolerance
      if (this%scf_count == this%max_scf_count) then
        if (debug%info) then
          message(1) = "Debug: -- Max SCF Iter reached for '" + trim(this%system%namespace%get()) + "'"
          call messages_info(1, namespace=this%system%namespace)
        end if
        this%inside_scf = .false.
        call this%next()
      else
        ! We reset the pointer to the beginning of the scf loop
        if (this%system%is_tolerance_reached(this%scf_tol)) then
          if (debug%info) then
            message(1) = "Debug: -- SCF tolerance reached for '" + trim(this%system%namespace%get()) + "'"
            call messages_info(1, namespace=this%system%namespace)
          end if
          this%inside_scf = .false.
          call this%next()
        else
          ! We rewind the instruction stack
          call this%rewind_scf_loop()
 
          ! We reset the clocks
          call this%system%reset_iteration_counters(this%accumulated_loop_ticks)
          this%accumulated_loop_ticks = 0
          if (debug%info) then
            write(message(1), '(a,i3,a,a)') "Debug: -- SCF iter ", this%scf_count, " for '" + trim(this%system%namespace%get()), "'"
            call messages_info(1, namespace=this%system%namespace)
          end if
        end if
      end if
 
    case default
      done = .false.
    end select
 
  end function propagator_do_operation
 
  ! ---------------------------------------------------------
  logical function propagator_finished(this)
    class(propagator_t), intent(in) :: this
 
    type(iteration_counter_t) :: clock_
 
    clock_ = this%system%iteration + 1
    propagator_finished = clock_%value() > this%final_time
 
  end function propagator_finished
 
  ! ---------------------------------------------------------
  subroutine propagator_init_iteration_counters(this)
    class(propagator_t), intent(inout) :: this
 
    this%iteration = clock_t(time_step=this%dt/this%algo_steps)
    this%system%iteration = clock_t(time_step=this%dt)
 
  end subroutine propagator_init_iteration_counters
 
  !
  subroutine propagator_save_scf_start(this)
    class(propagator_t), intent(inout) :: this
 
    push_sub(propagator_save_scf_start)
 
    this%scf_start = this%iter
    call this%next()
    this%scf_count = 0
 
    pop_sub(propagator_save_scf_start)
  end subroutine propagator_save_scf_start
 
  ! ---------------------------------------------------------
  !
  subroutine propagator_rewind_scf_loop(this)
    class(propagator_t), intent(inout) :: this
 
    push_sub(propagator_rewind_scf_loop)
 
    this%iter = this%scf_start
    call this%next()
    this%scf_count = this%scf_count + 1
 
    pop_sub(propagator_rewind_scf_loop)
  end subroutine propagator_rewind_scf_loop
 
end module propagator_oct_m
 
 
!! Local Variables:
!! mode: f90
!! coding: utf-8
!! End: