'not yet implemented'

def _updateCholesky(self, A, Ainv, p, alpha, beta):

    raise _Error('not    yet    implemented')
    alpha = float(alpha)
    beta = float(beta)
    y = np.dot(Ainv, p)
    y_sum = sum((y ** 2))
    tmp = sqrt((1 + ((beta * y_sum) / alpha)))
    fac = ((sqrt(alpha) / sum((y ** 2))) * (tmp - 1))
    facinv = ((1.0 / (sqrt(alpha) * sum((y ** 2)))) * (1 - (1.0 / tmp)))
    A *= sqrt(alpha)
    A += np.outer((fac * p), y)
    Ainv /= sqrt(alpha)
    Ainv -= np.outer((facinv * y), np.dot(y.T, Ainv))
