def analitStepDis((A, B, C, D), T):
    T = arange(T[0], T[1], T[2])
    J, V = eig(A)
    J = mt(J * eye(3, 3))
    V = mt(V)
    y = ([], [])
    for i in range(len(T)):
        y[0].append(T[i])
        yy = mt(((0, 0, 0))).transpose()
        for j in range(i - 1):
            yy = yy + matrix_power(A, i - 1 - j) * B
        yy = C * yy
        y[1].append(array(yy[0])[0][0])
    plot(y[0], y[1])
    title('Step construction')
    xlabel('t, s.')
    ylabel('y(t)')
    grid(color='g', linestyle='--')
    show()