adjoint_minimum_dissipation_source_term.f90

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!
! If the objective function $\int |\nabla u|^2$,
! the corresponding adjoint forcing is $ \int \nabla v \cdot \nabla u $ in weak
! form.
module adjoint_minimum_dissipation_source_term
  use num_types, only: rp
  use field_list, only: field_list_t
  use json_module, only: json_file
  use json_utils, only: json_get, json_get_or_default
  use source_term, only: source_term_t
  use coefs, only: coef_t
  use neko_config, only: neko_bcknd_device
  use utils, only: neko_error
  use field, only: field_t
  use field_math, only: field_subcol3, field_add2, field_add2s2
  use json_module, only: json_file
  use steady_simcomp, only: steady_simcomp_t
  use simcomp_executor, only: neko_simcomps
  use fluid_user_source_term, only: fluid_user_source_term_t
  use num_types, only: rp
  use field, only: field_t
  use field_registry, only: neko_field_registry
  use math, only: rzero, copy, chsign
  use device_math, only: device_copy, device_cmult
  use neko_config, only: neko_bcknd_device
  use operators, only: curl
  use scratch_registry, only: neko_scratch_registry
  use mask_ops, only: mask_exterior_const
  use point_zone, only: point_zone_t
  implicit none
  private
 
  ! $\int \nabla v \cdot \nabla u $
  type, public, extends(source_term_t) :: &
       adjoint_minimum_dissipation_source_term_t
     type(field_t), pointer :: u => null()
     type(field_t), pointer :: v => null()
     type(field_t), pointer :: w => null()
     real(kind=rp) :: obj_scale
     class(point_zone_t), pointer :: mask => null()
     logical :: if_mask
 
   contains
     procedure, pass(this) :: init => &
          adjoint_minimum_dissipation_source_term_init_from_json
     procedure, pass(this) :: init_from_components => &
          adjoint_minimum_dissipation_source_term_init_from_components
     procedure, pass(this) :: free => &
          adjoint_minimum_dissipation_source_term_free
     procedure, pass(this) :: compute_ => &
          adjoint_minimum_dissipation_source_term_compute
  end type adjoint_minimum_dissipation_source_term_t
 
contains
  subroutine adjoint_minimum_dissipation_source_term_init_from_json(this, &
       json, fields, coef, variable_name)
    class(adjoint_minimum_dissipation_source_term_t), intent(inout) :: this
    type(json_file), intent(inout) :: json
    type(field_list_t), intent(in), target :: fields
    type(coef_t), intent(in), target :: coef
    character(len=*), intent(in) :: variable_name
 
    ! we shouldn't be initializing this from JSON
    ! maybe throw an error?
 
 
  end subroutine adjoint_minimum_dissipation_source_term_init_from_json
 
  subroutine adjoint_minimum_dissipation_source_term_init_from_components(this,&
       f_x, f_y, f_z, &
       u, v, w, obj_scale, &
       mask, if_mask, &
       coef)
    class(adjoint_minimum_dissipation_source_term_t), intent(inout) :: this
    type(field_t), pointer, intent(in) :: f_x, f_y, f_z
    type(field_list_t) :: fields
    type(coef_t) :: coef
    real(kind=rp) :: start_time
    real(kind=rp) :: end_time
    real(kind=rp) :: obj_scale
    type(field_t), intent(in), target :: u, v, w
    class(point_zone_t), intent(in), target :: mask
    logical :: if_mask
 
    ! I wish you didn't need a start time and end time...
    ! but I'm just going to set a super big number...
    start_time = 0.0_rp
    end_time = 100000000.0_rp
 
    call this%free()
 
    ! this is copying the fluid source term init
    ! We package the fields for the source term to operate on in a field list.
    call fields%init(3)
    call fields%assign(1, f_x)
    call fields%assign(2, f_y)
    call fields%assign(3, f_z)
 
    call this%init_base(fields, coef, start_time, end_time)
 
    ! point everything in the correct places
    this%u => u
    this%v => v
    this%w => w
 
    this%obj_scale = obj_scale
 
    this%if_mask = if_mask
    if (this%if_mask) then
       this%mask => mask
    end if
 
  end subroutine adjoint_minimum_dissipation_source_term_init_from_components
 
  subroutine adjoint_minimum_dissipation_source_term_free(this)
    class(adjoint_minimum_dissipation_source_term_t), intent(inout) :: this
 
    call this%free_base()
  end subroutine adjoint_minimum_dissipation_source_term_free
 
  subroutine adjoint_minimum_dissipation_source_term_compute(this, t, tstep)
    class(adjoint_minimum_dissipation_source_term_t), intent(inout) :: this
    real(kind=rp), intent(in) :: t
    integer, intent(in) :: tstep
    type(field_t), pointer :: u, v, w
    type(field_t), pointer :: fu, fv, fw
    !type(field_t), pointer :: dudx, dudy, dudz
    !type(field_t), pointer :: dvdx, dvdy, dvdz
    !type(field_t), pointer :: dwdx, dwdy, dwdz
    type(field_t), pointer :: wo1, wo2, wo3, wo4, wo5, wo6
    type(field_t), pointer :: t1 , t2
    integer :: temp_indices(8)
    integer n
 
 
    fu => this%fields%get_by_index(1)
    fv => this%fields%get_by_index(2)
    fw => this%fields%get_by_index(3)
 
    n = fu%size()
 
    ! fuck I'm not sure about this... I need a pen and paper
    ! also there should be a way to pre-process this forcing term...
    ! instead of recalculating it every time
    u => this%u
    v => this%v
    w => this%w
    call neko_scratch_registry%request_field(wo1, temp_indices(1))
    call neko_scratch_registry%request_field(wo2, temp_indices(2))
    call neko_scratch_registry%request_field(wo3, temp_indices(3))
    call neko_scratch_registry%request_field(wo4, temp_indices(4))
    call neko_scratch_registry%request_field(wo5, temp_indices(5))
    call neko_scratch_registry%request_field(wo6, temp_indices(6))
    call neko_scratch_registry%request_field(t1 , temp_indices(7))
    call neko_scratch_registry%request_field(t2 , temp_indices(8))
 
    ! TODO
    ! ok we're computing gradients at every timestep... which is stupid...
    ! BUT
    ! if this was unsteady we would have to do this.
 
    ! TODO
    ! this is cheating a little bit...
    ! in strong form, \nabla u . \nabla v => - v . \nabla^2 u + bdry
    !
    ! we can do this properly later in weak form, ideally using ax_helm or so
    !
    ! for now we'll work in strong form and ignore the bdry
    ! and suffer the double derivative :/
    !
    ! in fact, we'll go even quicker and use
    ! \nabla ^2 u = grad (div (u)) - curl ( curl (u ))
    ! and assume divergence free u
 
    ! => - \nabla ^2 u =  curl ( curl (u ))
 
    call curl(wo1, wo2, wo3, u, v, w, t1, t2, this%coef)
    call curl(wo4, wo5, wo6, wo1, wo2, wo3, t1, t2, this%coef)
 
    ! mask
    if (this%if_mask) then
       call mask_exterior_const(wo4, this%mask, 0.0_rp)
       call mask_exterior_const(wo5, this%mask, 0.0_rp)
       call mask_exterior_const(wo6, this%mask, 0.0_rp)
    end if
 
    call field_add2s2(fu, wo4, this%obj_scale)
    call field_add2s2(fv, wo5, this%obj_scale)
    call field_add2s2(fw, wo6, this%obj_scale)
 
    ! don't worry... we'll write this MUCH cleaner in the final version
 
    call neko_scratch_registry%relinquish_field(temp_indices)
 
  end subroutine adjoint_minimum_dissipation_source_term_compute
 
end module adjoint_minimum_dissipation_source_term