def check_warm_start(name, random_state=42):
    # Test if fitting incrementally with warm start gives a forest of the
    # right size and the same results as a normal fit.
    X, y = hastie_X, hastie_y
    ForestEstimator = FOREST_ESTIMATORS[name]
    clf_ws = None
    for n_estimators in [5, 10]:
        if clf_ws is None:
            clf_ws = ForestEstimator(n_estimators=n_estimators,
                                     random_state=random_state,
                                     warm_start=True)
        else:
            clf_ws.set_params(n_estimators=n_estimators)
        clf_ws.fit(X, y)
        assert_equal(len(clf_ws), n_estimators)

    clf_no_ws = ForestEstimator(n_estimators=10, random_state=random_state,
                                warm_start=False)
    clf_no_ws.fit(X, y)

    assert_equal(set([tree.random_state for tree in clf_ws]),
                 set([tree.random_state for tree in clf_no_ws]))

    assert_array_equal(clf_ws.apply(X), clf_no_ws.apply(X),
                       err_msg="Failed with {0}".format(name))
dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/ensemble/tests/test_forest.py/check_warm_start/original