DirectAnnihilation Subroutine

    subroutine DirectAnnihilation(TotWalkersNew, MaxIndex, iter_data, err)

        integer, intent(inout) :: TotWalkersNew, MaxIndex
        integer, intent(out) :: err
        type(fcimc_iter_data), intent(inout) :: iter_data

        ! If the semi-stochastic approach is being used then the following routine performs the
        ! annihilation of the deterministic states. These states are subsequently skipped in the
        ! AnnihilateSpawnedParts routine.
        if (tSemiStochastic) call deterministic_annihilation(iter_data)

        ! Binary search the main list and copy accross/annihilate determinants which are found.
        ! This will also remove the found determinants from the spawnedparts lists.
        call AnnihilateSpawnedParts(MaxIndex, TotWalkersNew, iter_data, err)

        call set_timer(Sort_Time, 30)
        call CalcHashTableStats(TotWalkersNew, iter_data)
        call halt_timer(Sort_Time)

    end subroutine DirectAnnihilation