GetUMatSize Subroutine

    SUBROUTINE GetUMatSize(nBasis, iSize)
        use SystemData, only: tStoreSpinOrbs
        ! Get the prospective size of a UMat (not a UMatCache) for completely
        ! storing FCIDUMP 2-e integrals
        ! In:
        !    nBasis: as above.
        !    iSS: ratio of spatial orbitals to spin orbitals.
        !         iSS=0 integrals not stored in UMAT.
        !         iSS=1 unrestricted calculation
        !         iSS=2 restricted calculation
        !         iSS=-1 flag for the Hubbard model.
        ! Out:
        !    iSize: size of UMAT.
        INTEGER nBasis, iSS
        INTEGER iPairs, nBi
        INTEGER(int64), intent(out) :: iSize
        IF (tStoreSpinOrbs) THEN
            iSS = 1
        ELSE
            iSS = 2
        end if

        nBi = nBasis / iSS
        if (t_non_hermitian_2_body) then
            iPairs = nbi**2
        else
            iPairs = (nBi * (nBi + 1)) / 2
        end if
        iSize = (int(iPairs, int64) * int(iPairs + 1, int64)) / 2
#ifdef CMPLX_
        !Since we now only have 4-fold symmetry, rather than 8-fold.
        iSize = iSize * 2
#endif
    END SUBROUTINE GetUMatSize