def test_forest_classifier_serialization(
dataset_name,
n_estimators,
aggregation,
class_weight,
dirichlet,
n_jobs,
max_features,
random_state,
step,
multiclass,
cat_split_strategy,
):
if dataset_name == "adult":
X, y = load_adult(raw=True)
X_train, X_test, y_train, y_test = train_test_split(
X, y, random_state=random_state)
elif dataset_name == "iris":
iris = datasets.load_iris()
X = iris.data
y = iris.target
X_train, X_test, y_train, y_test = train_test_split(
X, y, test_size=1 / 5, random_state=random_state)
clf1 = ForestClassifier(
n_estimators=n_estimators,
n_jobs=n_jobs,
multiclass=multiclass,
max_bins=37,
cat_split_strategy=cat_split_strategy,
aggregation=aggregation,
max_features=max_features,
class_weight=class_weight,
random_state=random_state,
dirichlet=dirichlet,
step=step,
)
clf1.fit(X_train, y_train)
filename = "forest_classifier_on_iris.pkl"
with open(filename, "wb") as f:
pkl.dump(clf1, f)
with open(filename, "rb") as f:
clf2 = pkl.load(f)
os.remove(filename)
assert_forests_equal(clf1, clf2, is_classifier=True)
y_pred1 = clf1.predict_proba(X_test)
y_pred2 = clf2.predict_proba(X_test)
np.testing.assert_equal(y_pred1, y_pred2)
y_pred1 = clf1.predict(X_test)
y_pred2 = clf2.predict(X_test)
np.testing.assert_equal(y_pred1, y_pred2)
apply1 = clf1.apply(X_test)
apply2 = clf2.apply(X_test)
np.testing.assert_equal(apply1, apply2)
def test_class_weight_sample_weights(self):
iris = self.iris
X, y = iris["data"], iris["target"]
# Check that no sample_weight and all sample weights equal to 1. is the same
clf1 = ForestClassifier(class_weight=None, random_state=42)
clf1.fit(X, y)
clf2 = ForestClassifier(class_weight=None, random_state=42)
clf2.fit(X, y, sample_weight=np.ones(y.shape[0]))
assert clf1.apply(X) == approx(clf2.apply(X))
assert clf1.predict_proba(X) == approx(clf2.predict_proba(X))
clf1 = ForestClassifier(class_weight="balanced", random_state=42)
clf1.fit(X, y)
clf2 = ForestClassifier(class_weight=None, random_state=42)
sample_weight = compute_sample_weight("balanced", y)
clf2.fit(X, y, sample_weight=sample_weight)
assert clf1.apply(X) == approx(clf2.apply(X))
assert clf1.predict_proba(X) == approx(clf2.predict_proba(X))
# Simulate unbalanced data from the iris datasets
X_unb = np.concatenate((X[0:50], X[50:56], X[100:106]), axis=0)
y_unb = np.concatenate((y[0:50], y[50:56], y[100:106]), axis=0)
X_train, X_test, y_train, y_test = train_test_split(X_unb,
y_unb,
shuffle=True,
stratify=y_unb,
random_state=42,
test_size=0.5)
clf = ForestClassifier(class_weight=None,
random_state=42,
aggregation=True)
clf.fit(X_train, y_train)
y_scores = clf.predict(X_test)
report1 = classification_report(y_test, y_scores, output_dict=True)
clf = ForestClassifier(class_weight="balanced",
random_state=42,
aggregation=True)
clf.fit(X_train, y_train)
y_scores = clf.predict(X_test)
report2 = classification_report(y_test, y_scores, output_dict=True)
# In the considered case, class_weight should improve all metrics
for label in ["0", "1", "2"]:
label_report1 = report1[label]
label_report2 = report2[label]
assert label_report2["precision"] >= label_report1["precision"]
assert label_report2["recall"] >= label_report1["recall"]
assert label_report2["f1-score"] >= label_report1["f1-score"]
breast_cancer = self.breast_cancer
X, y = breast_cancer["data"], breast_cancer["target"]
idx_0 = y == 0
idx_1 = y == 1
X_unb = np.concatenate((X[idx_0], X[idx_1][:10]), axis=0)
y_unb = np.concatenate((y[idx_0], y[idx_1][:10]), axis=0)
X_train, X_test, y_train, y_test = train_test_split(X_unb,
y_unb,
shuffle=True,
stratify=y_unb,
random_state=42,
test_size=0.5)
clf = ForestClassifier(class_weight=None,
random_state=42,
aggregation=True)
clf.fit(X_train, y_train)
y_scores = clf.predict(X_test)
y_test_binary = LabelBinarizer().fit_transform(y_test)
avg_prec1 = average_precision_score(y_test_binary,
y_scores,
average="weighted")
clf = ForestClassifier(class_weight="balanced",
random_state=42,
aggregation=True)
clf.fit(X_train, y_train)
y_scores = clf.predict(X_test)
avg_prec2 = average_precision_score(y_test_binary,
y_scores,
average="weighted")
assert avg_prec2 > avg_prec1
