def testPredictSparseCallableKernel(self):
# This is a non-regression test for #15866
# Custom sparse kernel (top-K RBF)
def topk_rbf(X, Y=None, n_neighbors=10, gamma=1e-5):
nn = NearestNeighbors(n_neighbors=10,
metric='euclidean',
n_jobs=-1)
nn.fit(X)
W = -1 * mt.power(nn.kneighbors_graph(Y, mode='distance'),
2) * gamma
W = mt.exp(W)
assert W.issparse()
return W.T
n_classes = 4
n_samples = 500
n_test = 10
X, y = make_classification(n_classes=n_classes,
n_samples=n_samples,
n_features=20,
n_informative=20,
n_redundant=0,
n_repeated=0,
random_state=0)
X_train, X_test, y_train, y_test = train_test_split(X,
y,
test_size=n_test,
random_state=0)
model = LabelPropagation(kernel=topk_rbf)
model.fit(X_train, y_train)
assert model.score(X_test, y_test).fetch() >= 0.9
def testLabelPropagationClosedForm(self):
n_classes = 2
X, y = make_classification(n_classes=n_classes,
n_samples=200,
random_state=0)
y[::3] = -1
Y = np.zeros((len(y), n_classes + 1))
Y[np.arange(len(y)), y] = 1
unlabelled_idx = Y[:, (-1, )].nonzero()[0]
labelled_idx = (Y[:, (-1, )] == 0).nonzero()[0]
clf = LabelPropagation(max_iter=10000, gamma=0.1)
clf.fit(X, y)
# adopting notation from Zhu et al 2002
T_bar = clf._build_graph().to_numpy()
Tuu = T_bar[tuple(
np.meshgrid(unlabelled_idx, unlabelled_idx, indexing='ij'))]
Tul = T_bar[tuple(
np.meshgrid(unlabelled_idx, labelled_idx, indexing='ij'))]
Y = Y[:, :-1]
Y_l = Y[labelled_idx, :]
Y_u = np.dot(np.dot(np.linalg.inv(np.eye(Tuu.shape[0]) - Tuu), Tul),
Y_l)
expected = Y.copy()
expected[unlabelled_idx, :] = Y_u
expected /= expected.sum(axis=1)[:, np.newaxis]
np.testing.assert_array_almost_equal(expected,
clf.label_distributions_.fetch(),
4)
def testConvergenceWarning(self):
# This is a non-regression test for #5774
X = np.array([[1., 0.], [0., 1.], [1., 2.5]])
y = np.array([0, 1, -1])
mdl = LabelPropagation(kernel='rbf', max_iter=1)
assert_warns(ConvergenceWarning, mdl.fit, X, y)
assert mdl.n_iter_ == mdl.max_iter
mdl = LabelPropagation(kernel='rbf', max_iter=500)
assert_no_warnings(mdl.fit, X, y)