def test_gnb_sample_weight():
"""Test whether sample weights are properly used in GNB. """
# Sample weights all being 1 should not change results
sw = np.ones(6)
clf = GaussianNB().fit(X, y)
clf_sw = GaussianNB().fit(X, y, sw)
assert_array_almost_equal(clf.theta_, clf_sw.theta_)
assert_array_almost_equal(clf.sigma_, clf_sw.sigma_)
# Fitting twice with half sample-weights should result
# in same result as fitting once with full weights
sw = rng.rand(y.shape[0])
clf1 = GaussianNB().fit(X, y, sample_weight=sw)
clf2 = GaussianNB().partial_fit(X, y, classes=[1, 2], sample_weight=sw / 2)
clf2.partial_fit(X, y, sample_weight=sw / 2)
assert_array_almost_equal(clf1.theta_, clf2.theta_)
assert_array_almost_equal(clf1.sigma_, clf2.sigma_)
# Check that duplicate entries and correspondingly increased sample
# weights yield the same result
ind = rng.randint(0, X.shape[0], 20)
sample_weight = np.bincount(ind, minlength=X.shape[0])
clf_dupl = GaussianNB().fit(X[ind], y[ind])
clf_sw = GaussianNB().fit(X, y, sample_weight)
assert_array_almost_equal(clf_dupl.theta_, clf_sw.theta_)
assert_array_almost_equal(clf_dupl.sigma_, clf_sw.sigma_)
def test_gnb_partial_fit():
clf = GaussianNB().fit(X, y)
clf_pf = GaussianNB().partial_fit(X, y, np.unique(y))
assert_array_almost_equal(clf.theta_, clf_pf.theta_)
assert_array_almost_equal(clf.sigma_, clf_pf.sigma_)
assert_array_almost_equal(clf.class_prior_, clf_pf.class_prior_)
clf_pf2 = GaussianNB().partial_fit(X[0::2, :], y[0::2], np.unique(y))
clf_pf2.partial_fit(X[1::2], y[1::2])
assert_array_almost_equal(clf.theta_, clf_pf2.theta_)
assert_array_almost_equal(clf.sigma_, clf_pf2.sigma_)
assert_array_almost_equal(clf.class_prior_, clf_pf2.class_prior_)
