cache_sign Subroutine

    subroutine cache_sign(sgn, nIEx)
        integer, intent(in) :: nIEx(nel)
        real(dp), intent(in) :: sgn(lenof_sign)

        integer :: hash_value, ind
        real(dp) :: sign_tmp(lenof_sign)
        integer(n_int) :: ilut(0:NIfTot)
        logical :: tSuccess

        ! encode the determinant into bit representation (ilut)
        call EncodeBitDet(nIEx, ilut)
        call hash_table_lookup(nIEx, ilut, NIfD, hash_table_ciCoeff, &
                               ciCoeff_storage, ind, hash_value, tSuccess)
        ! tSuccess is true when the coeff is found in the hash_table; so it gets updated
        if (tSuccess) then
            call extract_sign(ciCoeff_storage(:, ind), sign_tmp)
            sign_tmp = sign_tmp + sgn
            call encode_sign(ciCoeff_storage(:, ind), sign_tmp)

            ! tSuccess is false, then add a new entry to the CI coeffs storage
        else
            ! it counts the number of entries of different CI coeffs
            first_free_entry = first_free_entry + 1
            ! encode the determinant into bit representation (ilut)
            call EncodeBitDet(nIEx, ilut)
            ! store the encoded determinant in ciCoeff_storage
            ciCoeff_storage(:, first_free_entry) = ilut
            ! store the sign in ciCoeff_storage
            call encode_sign(ciCoeff_storage(:, first_free_entry), sgn)
            ! create a new hashtable entry
            call add_hash_table_entry(hash_table_ciCoeff, &
                                      first_free_entry, hash_value)
        end if
    end subroutine cache_sign