read_kipf Subroutine

  subroutine read_kipf(this, unit, verbose)
    !! Read the message passing layer
    use athena__tools_infile, only: assign_val, assign_vec, get_val, move
    use coreutils, only: to_lower, to_upper, icount
    use athena__activation, only: read_activation
    use athena__initialiser, only: initialiser_setup
    implicit none

    ! Arguments
    class(kipf_msgpass_layer_type), intent(inout) :: this
    !! Instance of the message passing layer
    integer, intent(in) :: unit
    !! Unit to read from
    integer, optional, intent(in) :: verbose
    !! Verbosity level

    ! Local variables
    integer :: stat
    !! Status of read
    integer :: verbose_ = 0
    !! Verbosity level
    integer :: t, j, k, c, itmp1, iline
    !! Loop variables and temporary integer
    integer :: num_time_steps = 0
    !! Number of time steps
    character(14) :: kernel_initialiser_name=''
    !! Initialisers
    character(20) :: activation_name=''
    !! Activation function name
    class(base_actv_type), allocatable :: activation
    !! Activation function
    class(base_init_type), allocatable :: kernel_initialiser
    !! Initialisers
    integer, dimension(:), allocatable :: num_vertex_features
    !! Number of vertex and edge features
    character(256) :: buffer, tag, err_msg
    !! Buffer, tag, and error message
    real(real32), allocatable, dimension(:) :: data_list
    !! Data list
    integer :: param_line, final_line
    !! Parameter line number


    ! Initialise optional arguments
    !---------------------------------------------------------------------------
    if(present(verbose)) verbose_ = verbose


    ! Loop over tags in layer card
    !---------------------------------------------------------------------------
    iline = 0
    param_line = 0
    final_line = 0
    tag_loop: do

       ! Check for end of file
       !------------------------------------------------------------------------
       read(unit,'(A)',iostat=stat) buffer
       if(stat.ne.0)then
          write(err_msg,'("file encountered error (EoF?) before END ",A)') &
               to_upper(this%name)
          call stop_program(err_msg)
          return
       end if
       if(trim(adjustl(buffer)).eq."") cycle tag_loop

       ! Check for end of layer card
       !------------------------------------------------------------------------
       if(trim(adjustl(buffer)).eq."END "//to_upper(trim(this%name)))then
          final_line = iline
          backspace(unit)
          exit tag_loop
       end if
       iline = iline + 1

       tag=trim(adjustl(buffer))
       if(scan(buffer,"=").ne.0) tag=trim(tag(:scan(tag,"=")-1))

       ! Read parameters from file
       !------------------------------------------------------------------------
       select case(trim(tag))
       case("NUM_TIME_STEPS")
          call assign_val(buffer, num_time_steps, itmp1)
       case("NUM_VERTEX_FEATURES")
          itmp1 = icount(get_val(buffer))
          allocate(num_vertex_features(itmp1), source=0)
          call assign_vec(buffer, num_vertex_features, itmp1)
       case("ACTIVATION")
          iline = iline - 1
          backspace(unit)
          activation = read_activation(unit, iline)
       case("KERNEL_INITIALISER", "KERNEL_INIT", "KERNEL_INITIALisER")
          call assign_val(buffer, kernel_initialiser_name, itmp1)
       case("WEIGHTS")
          kernel_initialiser_name = 'zeros'
          param_line = iline
       case default
          ! Don't look for "e" due to scientific notation of numbers
          ! ... i.e. exponent (E+00)
          if(scan(to_lower(trim(adjustl(buffer))),&
               'abcdfghijklmnopqrstuvwxyz').eq.0)then
             cycle tag_loop
          elseif(tag(:3).eq.'END')then
             cycle tag_loop
          end if
          write(err_msg,'("Unrecognised line in input file: ",A)') &
               trim(adjustl(buffer))
          call stop_program(err_msg)
          return
       end select
    end do tag_loop
    kernel_initialiser = initialiser_setup(kernel_initialiser_name)


    ! Set hyperparameters and initialise layer
    !---------------------------------------------------------------------------
    if(num_time_steps.gt.0 .and. num_time_steps.ne.size(num_vertex_features,1)-1)then
       write(err_msg,'("NUM_TIME_STEPS = ",I0," does not match length of "// &
            &"NUM_VERTEX_FEATURES = ",I0)') num_time_steps, &
            size(num_vertex_features,1)-1
       call stop_program(err_msg)
       return
    end if
    call this%set_hyperparams( &
         num_time_steps = num_time_steps, &
         num_vertex_features = num_vertex_features, &
         activation = activation, &
         kernel_initialiser = kernel_initialiser, &
         verbose = verbose_ &
    )
    call this%init(input_shape=[this%num_vertex_features(0), 0])


    ! Check if WEIGHTS card was found
    !---------------------------------------------------------------------------
    if(param_line.eq.0)then
       write(0,*) "WARNING: WEIGHTS card in "//to_upper(trim(this%name))//" not found"
    else
       call move(unit, param_line - iline, iostat=stat)
       do t = 1, this%num_time_steps
          allocate(data_list(this%num_params_msg(t)), source=0._real32)
          c = 1
          k = 1
          data_concat_loop: do while(c.le.this%num_params_msg(t))
             read(unit,'(A)',iostat=stat) buffer
             if(stat.ne.0) exit data_concat_loop
             k = icount(buffer)
             read(buffer,*,iostat=stat) (data_list(j),j=c,c+k-1)
             c = c + k
          end do data_concat_loop
          this%params(t)%val(:,1) = data_list(1:this%num_params_msg(t))
          deallocate(data_list)
       end do

       ! Check for end of weights card
       !------------------------------------------------------------------------
       read(unit,'(A)') buffer
       if(trim(adjustl(buffer)).ne."END WEIGHTS")then
          write(0,*) trim(adjustl(buffer))
          call stop_program("END WEIGHTS not where expected")
          return
       end if
    end if


    !---------------------------------------------------------------------------
    ! Check for end of layer card
    !---------------------------------------------------------------------------
    read(unit,'(A)') buffer
    if(trim(adjustl(buffer)).ne."END "//to_upper(trim(this%name)))then
       write(0,*) trim(adjustl(buffer))
       write(err_msg,'("END ",A," not where expected")') to_upper(this%name)
       call stop_program(err_msg)
       return
    end if

  end subroutine read_kipf