test_ranking.py 文件源码

def test_precision_recall_curve():
    y_true, _, probas_pred = make_prediction(binary=True)
    _test_precision_recall_curve(y_true, probas_pred)

    # Use {-1, 1} for labels; make sure original labels aren't modified
    y_true[np.where(y_true == 0)] = -1
    y_true_copy = y_true.copy()
    _test_precision_recall_curve(y_true, probas_pred)
    assert_array_equal(y_true_copy, y_true)

    labels = [1, 0, 0, 1]
    predict_probas = [1, 2, 3, 4]
    p, r, t = precision_recall_curve(labels, predict_probas)
    assert_array_almost_equal(p, np.array([0.5, 0.33333333, 0.5, 1., 1.]))
    assert_array_almost_equal(r, np.array([1., 0.5, 0.5, 0.5, 0.]))
    assert_array_almost_equal(t, np.array([1, 2, 3, 4]))
    assert_equal(p.size, r.size)
    assert_equal(p.size, t.size + 1)