ensemble.F90

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!! Copyright (C) 2024 S. de la Pena, M. Lueders
!!
!! 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 ensemble_oct_m
 
  use algorithm_oct_m
  use debug_oct_m
  use global_oct_m
  use interactions_factory_abst_oct_m
  use interaction_partner_oct_m
  use io_oct_m
  use messages_oct_m
  use mpi_oct_m
  use multisystem_basic_oct_m
  use multisystem_oct_m
  use namespace_oct_m
  use system_factory_abst_oct_m
  use system_oct_m
  use parser_oct_m
  use profiling_oct_m
 
  implicit none
 
  private
  public ::               &
    ensemble_t
 
  type, extends(multisystem_t) :: ensemble_t
    private
    integer                   :: nreplica
    !                                        !!
    !                                        !! This is the number of replicas in, planned for a calculation.
    !                                        !! The actual number of replicas in one run is determined by
    !                                        !! last-first+1.
    !                                        !!
    !                                        !! The total number of replicas can be different can differ if
    !                                        !! further runs have been added to improve the convergence.
    integer                   :: first
    integer                   :: last
    real(real64), allocatable :: weights(:)
 
  contains
    procedure :: create_interactions => ensemble_create_interactions
    procedure :: add_partners_to_list => ensemble_add_partners_to_list
    final :: ensemble_finalizer
  end type ensemble_t
 
  interface ensemble_t
    procedure ensemble_constructor
  end interface ensemble_t
 
contains
 
  ! ---------------------------------------------------------
  !
  recursive function ensemble_constructor(namespace, n_replicas, first, last, system_factory, names, types, calc_mode_id, grp) &
    result(sys)
    type(namespace_t),                  intent(in) :: namespace
    integer,                            intent(in) :: n_replicas
    class(system_factory_abst_t),       intent(in) :: system_factory
    integer,                            intent(in) :: first
    integer,                            intent(in) :: last
    character(len=128),                 intent(in) :: names(:)
    integer,                            intent(in) :: types(:)
    integer,                            intent(in) :: calc_mode_id
    type(mpi_grp_t),                    intent(in) :: grp
    class(ensemble_t), pointer    :: sys
 
    integer                  :: ireplica
    class(system_t), pointer :: replica
    character(len=128)       :: replica_name
 
    push_sub(ensemble_constructor)
 
    allocate(sys)
    sys%namespace = namespace
    sys%nreplica = n_replicas
    sys%first = max(1, first)
    sys%last = min(n_replicas, last)
 
 
    ! No interaction directly supported by this system (but classes that extend it can add their own)
    allocate(sys%supported_interactions(0))
    allocate(sys%supported_interactions_as_partner(0))
 
    do ireplica = sys%first, sys%last
      write(replica_name, '(I8.8)') ireplica
 
      ! Be aware that we need to use `sys%namespace` here. Passing only `namespace` leads to an error,
      ! as `namespace` seems to be deleted when the routine exits.
      !
      replica => multisystem_basic_t(namespace_t(replica_name, parent=sys%namespace), names, types, &
        system_factory, calc_mode_id, grp)
 
      call sys%list%add(replica)
 
    end do
 
    ! Initialize weights to uniform distribution
 
    safe_allocate(sys%weights(1:sys%nreplica))
    sys%weights = 1.0_real64/sys%nreplica
 
    pop_sub(ensemble_constructor)
  end function ensemble_constructor
 
  recursive subroutine ensemble_finalizer(this)
    type(ensemble_t), intent(inout) :: this
 
    push_sub(ensemble_finalizer)
 
    call ensemble_end(this)
 
    pop_sub(ensemble_finalizer)
  end subroutine ensemble_finalizer
 
  recursive subroutine ensemble_end(this)
    type(ensemble_t), intent(inout) :: this
 
    push_sub(ensemble_end)
 
    safe_deallocate_a(this%weights)
    call multisystem_end(this)
 
    pop_sub(ensemble_end)
  end subroutine ensemble_end
 
  ! ---------------------------------------------------------
  !
  recursive subroutine ensemble_create_interactions(this, interaction_factory, available_partners)
    class(ensemble_t),                   intent(inout) :: this
    class(interactions_factory_abst_t),  intent(in)    :: interaction_factory
    class(partner_list_t),       target, intent(in)    :: available_partners
 
    type(system_iterator_t) :: iter
    class(system_t), pointer :: subsystem
    type(partner_list_t) :: partners
 
    push_sub(ensemble_create_interactions)
 
    ! Create interactions of the ensemble container
    call system_create_interactions(this, interaction_factory, available_partners)
 
    ! Create the subsystems interactions
    call iter%start(this%list)
    do while (iter%has_next())
      subsystem => iter%get_next()
      ! partners = available_partners
      ! the above line would provide inter-replica ghost interactions, which does not seem
      ! to be necessary, as the replicas can propagate independent of each other.
      ! If we need more synchronization, e.g. for averages, this should be provided by the
      ! real interaction.
      ! In order to restore the inter-replica ghost, uncomment the line above and remove
      ! the line below (partners.empty()).
      call partners%empty()
      call partners%add(subsystem)
      call subsystem%create_interactions(interaction_factory, partners)
    end do
 
    pop_sub(ensemble_create_interactions)
  end subroutine ensemble_create_interactions
 
 
  recursive subroutine ensemble_add_partners_to_list(this, list, interaction_type)
    class(ensemble_t),        intent(in)    :: this
    class(partner_list_t),    intent(inout) :: list
    integer,        optional, intent(in)    :: interaction_type
 
    type(system_iterator_t) :: iter
    class(system_t), pointer :: system
 
    push_sub(ensemble_add_partners_to_list)
 
    if (present(interaction_type)) then
      if (any(this%supported_interactions_as_partner == interaction_type)) then
        call list%add(this)
      end if
    else
      call list%add(this)
 
      call iter%start(this%list)
      do while (iter%has_next())
        system => iter%get_next()
        call system%add_partners_to_list(list)
      end do
 
    end if
 
    pop_sub(ensemble_add_partners_to_list)
  end subroutine ensemble_add_partners_to_list
 
end module ensemble_oct_m