read_parameters Subroutine

  subroutine read_parameters(le_grid_config_in)
    use file_utils, only: error_unit
    use text_options, only: text_option, get_option_value
    implicit none
    type(le_grids_config_type), intent(in), optional :: le_grid_config_in    
    type (text_option), dimension (4), parameter :: wfbbcopts = &
         (/ text_option('default', wfbbc_option_mixed), &
            text_option('passing', wfbbc_option_passing), &
            text_option('trapped', wfbbc_option_trapped), &
            text_option('mixed', wfbbc_option_mixed)/)
    character(20) :: wfbbc_option
    integer :: ierr
    
    if (present(le_grid_config_in)) le_grids_config = le_grid_config_in

    call le_grids_config%init(name = 'le_grids_knobs', requires_index = .false.)

    ! Copy out internal values into module level parameters
    bouncefuzz = le_grids_config%bouncefuzz
    genquad = le_grids_config%genquad
    negrid = le_grids_config%negrid
    nesub = le_grids_config%nesub
    nesuper = le_grids_config%nesuper
    new_trap_int = le_grids_config%new_trap_int
    new_trap_int_split = le_grids_config%new_trap_int_split
    npassing = le_grids_config%npassing
    ngauss = le_grids_config%ngauss
    nmax = le_grids_config%nmax
    radau_gauss_grid = le_grids_config%radau_gauss_grid
    split_passing_region = le_grids_config%split_passing_region
    test = le_grids_config%test
    trapped_particles = le_grids_config%trapped_particles
    vcut = le_grids_config%vcut
    wfbbc_option = le_grids_config%wfbbc_option
    wgt_fac = le_grids_config%wgt_fac

    exist = le_grids_config%exist
    
! user can choose not to set negrid (preferred for old scheme)
    if (negrid == -10) then
       negrid = nesub + nesuper

! If user chose negrid, then set nesuper and nesub accordingly
    else 
       nesuper = min(negrid/10+1, 4)
       nesub = negrid - nesuper
    endif

    ! Set ng2 from ngauss if not specified in the input file
    if (npassing < 0) then
       ng2 = 2 * ngauss
    else
       ng2 = npassing
    end if

    ierr = error_unit()

    call get_option_value &
         (wfbbc_option, wfbbcopts, wfbbc_option_switch, &
         ierr, "wfbbc_option in dist_fn_knobs",.true.)

    trapped_wfb = .false.! flag for treating wfb as a trapped particle
    passing_wfb = .false.! flag for treating wfb as a passing particle

    select case (wfbbc_option_switch)
    case(wfbbc_option_mixed) ! The previous default boundary condition which mixes the passing and trapped boundary conditions
       passing_wfb =.false.
       trapped_wfb =.false.
    case(wfbbc_option_passing) ! Treats wfb using a passing particle boundary condition
       passing_wfb =.true.
       trapped_wfb =.false.
    case(wfbbc_option_trapped) ! Treats the wfb using a trapped particle boundary condition
       passing_wfb =.false.
       trapped_wfb =.true.
    end select
    mixed_wfb = (.not. passing_wfb) .and. (.not. trapped_wfb)
  end subroutine read_parameters