Sub MNEWT(NTRIAL, X(), N, TOLX, TOLF)
    Dim ALPHA(15, 15), BETA(15), INDX(15)
    For K = 1 To NTRIAL
        Call USRFUN(X(), ALPHA(), BETA())
        ERRF = 0#
        For I = 1 To N
            ERRF = ERRF + Abs(BETA(I))
        Next I
        If ERRF <= TOLF Then Exit Sub
        Call LUDCMP(ALPHA(), N, INDX(), D)
        Call LUBKSB(ALPHA(), N, INDX(), BETA())
        ERRX = 0#
        For I = 1 To N
            ERRX = ERRX + Abs(BETA(I))
            X(I) = X(I) + BETA(I)
        Next I
        If ERRX <= TOLX Then Exit Sub
    Next K
End Sub