GAS_doubles_PCHB_finalize Subroutine

    subroutine GAS_doubles_PCHB_finalize(this)
        class(GAS_PCHB_DoublesSpatOrbFastWeightedExcGenerator_t), intent(inout) :: this

        if (allocated(this%particle_selector)) then
            call this%pchb_samplers%finalize()
            call this%particle_selector%finalize()
            ! Yes we assume that either all or none are allocated.
            deallocate(this%particle_selector, this%tgtOrbs, this%pExch, this%indexer)
            if (this%create_lookup) then
                nullify(lookup_supergroup_indexer)
            end if
        end if
    end subroutine GAS_doubles_PCHB_finalize