Init_AMRController2D Subroutine

  subroutine Init_AMRController2D(this,model,refineThreshold,coarsenThreshold,ivar, &
                                  maxLevel,nHalo,relativeEnergyFloor,energyWeights, &
                                  significantEnergyFloor)
    !! Attach the controller to an initialized model. The model's current mesh becomes the
    !! forest's base mesh (level 0); its geometry interpolant drives the indicator and the
    !! solution transfer. Thresholds are the sigma = log10 modal-energy-ratio cut-offs of the
    !! refinement indicator (refineThreshold > coarsenThreshold; see
    !! SELF_RefinementIndicator_2D). ivar is the driving solution variable (or
    !! SELF_AMR_ALLVARS). maxLevel >= 0 caps the refinement depth; nHalo >= 0 sets the
    !! refine-flag halo width in elements.
    !!
    !! relativeEnergyFloor tunes the indicator's amplitude gate: an element whose energy is below
    !! this fraction of the field's peak element energy is treated as quiescent (hence resolved)
    !! regardless of its modal shape, which is what allows the mesh to be released behind a
    !! passing front. It is an energy fraction, so the square of the corresponding amplitude
    !! fraction; 0 disables the gate. energyWeights optionally weights the per-variable energies
    !! that form the gate, e.g. from the model's entropy function - see
    !! RefinementIndicator2D%SetEnergyWeights. significantEnergyFloor opens a hysteresis band on
    !! the energy axis: elements between the two floors hold their mesh (SELF_AMR_KEEP) instead of
    !! flipping across a single hard cut. All three default to the indicator's own defaults.
    implicit none
    class(AMRController2D),intent(out) :: this
    class(DGModel2D_t),intent(in) :: model
    real(prec),intent(in) :: refineThreshold
    real(prec),intent(in) :: coarsenThreshold
    integer,intent(in) :: ivar
    integer,intent(in) :: maxLevel
    integer,intent(in) :: nHalo
    real(prec),intent(in),optional :: relativeEnergyFloor
    real(prec),intent(in),optional :: energyWeights(:)
    real(prec),intent(in),optional :: significantEnergyFloor

    if(.not. associated(model%mesh)) then
      print*,__FILE__,':',__LINE__, &
        ' : Error : AMRController2D%Init requires an initialized model.'
      stop 1
    endif
    if(maxLevel < 0 .or. nHalo < 0) then
      print*,__FILE__,':',__LINE__, &
        ' : Error : AMRController2D%Init requires maxLevel >= 0 and nHalo >= 0.'
      stop 1
    endif

    this%baseMesh => model%mesh
    this%activeMesh => model%mesh
    this%activeGeom => model%geometry
    this%interp => model%geometry%x%interp
    this%ownsActive = .false.
    this%ivar = ivar
    this%maxLevel = maxLevel
    this%nHalo = nHalo
    this%refineThreshold = refineThreshold
    this%coarsenThreshold = coarsenThreshold
    if(present(relativeEnergyFloor)) then
      this%relativeEnergyFloor = relativeEnergyFloor
      this%significantEnergyFloor = relativeEnergyFloor
    endif
    if(present(significantEnergyFloor)) this%significantEnergyFloor = significantEnergyFloor
    if(present(energyWeights)) then
      allocate(this%energyWeights(1:size(energyWeights)))
      this%energyWeights = energyWeights
    endif

    ! Rank-replicated forest: on one rank, straight from the mesh; on several, from the
    ! allgathered global base tables (every rank builds the identical forest).
    if(model%mesh%decomp%nRanks > 1) then
      call InitForestFromDecomposedMesh(this%forest,model%mesh)
    else
      call this%forest%Init(model%mesh)
    endif
    call this%indicator%Init(this%interp,model%mesh%nElem,refineThreshold,coarsenThreshold)
    call this%ApplyIndicatorSettings()

  endsubroutine Init_AMRController2D