Sub FGAUSS(X, A(), Y, DYDA(), NA)
    Y = 0#
    For I = 1 To NA - 1 Step 3
        ARG = (X - A(I + 1)) / A(I + 2)
        EX = Exp(-ARG ^ 2)
        FAC = A(I) * EX * 2# * ARG
        Y = Y + A(I) * EX
        DYDA(I) = EX
        DYDA(I + 1) = FAC / A(I + 2)
        DYDA(I + 2) = FAC * ARG / A(I + 2)
    Next I
End Sub