MODULE df1dim

    PUBLIC ncom, pcom(50), xicom(50)   ! Labelled COMMOM /F1COM/

    FUNCTION df1dim (x)

        ! The subroutine dfunc is supplied by the user

        DIM xt(0), df(0)
        MAT redim xt(ncom), df(ncom)

        FOR j = 1 to ncom
            LET xt(j) = pcom(j) + x * xicom(j)
        NEXT j

        CALL dfunc (xt(), df())

        LET df1 = 0
        FOR j = 1 to ncom
            LET df1 = df1 + df(j) * xicom(j)
        NEXT j
        LET df1dim = df1

    END FUNCTION

END MODULE