def test_stacking_regressor_diabetes(cv, final_estimator, predict_params,
passthrough):
# prescale the data to avoid convergence warning without using a pipeline
# for later assert
X_train, X_test, y_train, _ = train_test_split(scale(X_diabetes),
y_diabetes,
random_state=42)
estimators = [('lr', LinearRegression()), ('svr', LinearSVR())]
reg = StackingRegressor(estimators=estimators,
final_estimator=final_estimator,
cv=cv,
passthrough=passthrough)
reg.fit(X_train, y_train)
result = reg.predict(X_test, **predict_params)
expected_result_length = 2 if predict_params else 1
if predict_params:
assert len(result) == expected_result_length
X_trans = reg.transform(X_test)
expected_column_count = 12 if passthrough else 2
assert X_trans.shape[1] == expected_column_count
if passthrough:
assert_allclose(X_test, X_trans[:, -10:])
reg.set_params(lr='drop')
reg.fit(X_train, y_train)
reg.predict(X_test)
X_trans = reg.transform(X_test)
expected_column_count_drop = 11 if passthrough else 1
assert X_trans.shape[1] == expected_column_count_drop
if passthrough:
assert_allclose(X_test, X_trans[:, -10:])
def test_stacking_regressor_drop_estimator():
# prescale the data to avoid convergence warning without using a pipeline
# for later assert
X_train, X_test, y_train, _ = train_test_split(scale(X_diabetes),
y_diabetes,
random_state=42)
estimators = [('lr', 'drop'), ('svr', LinearSVR(random_state=0))]
rf = RandomForestRegressor(n_estimators=10, random_state=42)
reg = StackingRegressor(estimators=[('svr', LinearSVR(random_state=0))],
final_estimator=rf,
cv=5)
reg_drop = StackingRegressor(estimators=estimators,
final_estimator=rf,
cv=5)
reg.fit(X_train, y_train)
reg_drop.fit(X_train, y_train)
assert_allclose(reg.predict(X_test), reg_drop.predict(X_test))
assert_allclose(reg.transform(X_test), reg_drop.transform(X_test))
def test_stacking_regressor_sparse_passthrough(fmt):
# Check passthrough behavior on a sparse X matrix
X_train, X_test, y_train, _ = train_test_split(
sparse.coo_matrix(scale(X_diabetes)).asformat(fmt),
y_diabetes, random_state=42
)
estimators = [('lr', LinearRegression()), ('svr', LinearSVR())]
rf = RandomForestRegressor(n_estimators=10, random_state=42)
clf = StackingRegressor(
estimators=estimators, final_estimator=rf, cv=5, passthrough=True
)
clf.fit(X_train, y_train)
X_trans = clf.transform(X_test)
assert_allclose_dense_sparse(X_test, X_trans[:, -10:])
assert sparse.issparse(X_trans)
assert X_test.format == X_trans.format
