test_t_sne.py 文件源码

def test_binary_perplexity_stability():
    # Binary perplexity search should be stable.
    # The binary_search_perplexity had a bug wherein the P array
    # was uninitialized, leading to sporadically failing tests.
    k = 10
    n_samples = 100
    random_state = check_random_state(0)
    distances = random_state.randn(n_samples, 2).astype(np.float32)
    # Distances shouldn't be negative
    distances = np.abs(distances.dot(distances.T))
    np.fill_diagonal(distances, 0.0)
    last_P = None
    neighbors_nn = np.argsort(distances, axis=1)[:, :k].astype(np.int64)
    for _ in range(100):
        P = _binary_search_perplexity(distances.copy(), neighbors_nn.copy(),
                                      3, verbose=0)
        P1 = _joint_probabilities_nn(distances, neighbors_nn, 3, verbose=0)
        if last_P is None:
            last_P = P
            last_P1 = P1
        else:
            assert_array_almost_equal(P, last_P, decimal=4)
            assert_array_almost_equal(P1, last_P1, decimal=4)