test_mlp.py 文件源码

def test_alpha():
    # Test that larger alpha yields weights closer to zero"""
    X = X_digits_binary[:100]
    y = y_digits_binary[:100]

    alpha_vectors = []
    alpha_values = np.arange(2)
    absolute_sum = lambda x: np.sum(np.abs(x))

    for alpha in alpha_values:
        mlp = MLPClassifier(hidden_layer_sizes=10, alpha=alpha, random_state=1)
        mlp.fit(X, y)
        alpha_vectors.append(np.array([absolute_sum(mlp.coefs_[0]),
                                       absolute_sum(mlp.coefs_[1])]))

    for i in range(len(alpha_values) - 1):
        assert (alpha_vectors[i] > alpha_vectors[i + 1]).all()