maxpool1d Module Function

  module function maxpool1d(input, pool_size, stride) result(output)
    !! 1D max pooling operation
    implicit none

    ! Arguments
    type(array_type), intent(in), target :: input
    integer, intent(in) :: pool_size
    integer, intent(in) :: stride
    type(array_type), pointer :: output

    ! Local variables
    integer :: i, m, s
    integer :: stride_idx, idx
    integer, dimension(3) :: output_shape

    output_shape = [ &
         (input%shape(1) - pool_size) / stride + 1, &
         input%shape(2), &
         size(input%val, dim=2)]
    output => input%create_result(array_shape = output_shape)
    do concurrent(&
         s = 1:output_shape(3), &
         m = 1:output_shape(2), &
         i = 1:output_shape(1))
       stride_idx = (i - 1) * stride + (m - 1) * input%shape(1)
       idx = i + (m - 1) * output_shape(1)
       output%val(idx, s) = maxval( &
            input%val( stride_idx + 1 : stride_idx + pool_size, s ) &
       )
    end do
    allocate(output%adj_ja(1,2))
    output%adj_ja(1,1) = pool_size
    output%adj_ja(1,2) = stride

    output%get_partial_left => get_partial_maxpool1d
    output%get_partial_left_val => get_partial_maxpool1d_val
    if(input%requires_grad)then
       output%requires_grad = .true.
       output%is_forward = input%is_forward
       output%operation = 'maxpool'
       output%left_operand => input
    end if

  end function maxpool1d