test_extmath.py 文件源码

def test_logistic_sigmoid():
    # Check correctness and robustness of logistic sigmoid implementation
    def naive_log_logistic(x):
        return np.log(1 / (1 + np.exp(-x)))

    x = np.linspace(-2, 2, 50)
    assert_array_almost_equal(log_logistic(x), naive_log_logistic(x))

    extreme_x = np.array([-100., 100.])
    assert_array_almost_equal(log_logistic(extreme_x), [-100, 0])