remove_repeated_states Subroutine

    subroutine remove_repeated_states(list, list_size)

        use DetBitOps, only: ilut_lt, ilut_gt
        use sort_mod, only: sort

        integer, intent(inout) :: list_size
        integer(n_int), intent(inout) :: list(0:, :)
        integer :: i, counter

        if (list_size > 0) then
            ! Annihilation-like steps to remove repeated states.
            call sort(list(:, 1:list_size), ilut_lt, ilut_gt)
            counter = 1
            do i = 2, list_size
                ! If this state and the previous one were identical, don't add this state to the
                ! list so that repeats aren't included.
                if (.not. all(list(0:nifd, i - 1) == list(0:nifd, i))) then
                    counter = counter + 1
                    list(:, counter) = list(:, i)
                end if
            end do

            list_size = counter
        end if

    end subroutine remove_repeated_states