def test_class_weights():
# Test class weights.
X = np.array([[-1.0, -1.0], [-1.0, 0], [-.8, -1.0], [1.0, 1.0], [1.0,
0.0]])
y = [1, 1, 1, -1, -1]
clf = RidgeClassifier(class_weight=None)
clf.fit(X, y)
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([1]))
# we give a small weights to class 1
clf = RidgeClassifier(class_weight={1: 0.001})
clf.fit(X, y)
# now the hyperplane should rotate clock-wise and
# the prediction on this point should shift
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([-1]))
# check if class_weight = 'balanced' can handle negative labels.
clf = RidgeClassifier(class_weight='balanced')
clf.fit(X, y)
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([1]))
# class_weight = 'balanced', and class_weight = None should return
# same values when y has equal number of all labels
X = np.array([[-1.0, -1.0], [-1.0, 0], [-.8, -1.0], [1.0, 1.0]])
y = [1, 1, -1, -1]
clf = RidgeClassifier(class_weight=None)
clf.fit(X, y)
clfa = RidgeClassifier(class_weight='balanced')
clfa.fit(X, y)
assert_equal(len(clfa.classes_), 2)
assert_array_almost_equal(clf.coef_, clfa.coef_)
assert_array_almost_equal(clf.intercept_, clfa.intercept_)
class RidgeClassifierImpl():
def __init__(self,
alpha=1.0,
fit_intercept=True,
normalize=False,
copy_X=True,
max_iter=None,
tol=0.001,
class_weight='balanced',
solver='auto',
random_state=None):
self._hyperparams = {
'alpha': alpha,
'fit_intercept': fit_intercept,
'normalize': normalize,
'copy_X': copy_X,
'max_iter': max_iter,
'tol': tol,
'class_weight': class_weight,
'solver': solver,
'random_state': random_state
}
def fit(self, X, y=None):
self._sklearn_model = SKLModel(**self._hyperparams)
if (y is not None):
self._sklearn_model.fit(X, y)
else:
self._sklearn_model.fit(X)
return self
def predict(self, X):
return self._sklearn_model.predict(X)
def test_class_weights():
"""
Test class weights.
"""
X = np.array([[-1.0, -1.0], [-1.0, 0], [-.8, -1.0], [1.0, 1.0], [1.0,
0.0]])
y = [1, 1, 1, -1, -1]
clf = RidgeClassifier(class_weight=None)
clf.fit(X, y)
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([1]))
# we give a small weights to class 1
clf = RidgeClassifier(class_weight={1: 0.001})
clf.fit(X, y)
# now the hyperplane should rotate clock-wise and
# the prediction on this point should shift
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([-1]))
