MAINT: Deprecate BalanceCascade sampler (#472)

Author: glemaitre

doc/whats_new/v0.0.4.rst

@@ -144,3 +144,6 @@ Deprecation
   :class:`imblearn.ensemble.EasyEnsembleClassifier` which follow the exact
   algorithm described in the literature.
   :issue:`455` by :user:`Guillaume Lemaitre <glemaitre>`.
+
+- Deprecate :class:`imblearn.ensemble.BalanceCascade`.
+  :issue:`472` by :user:`Guillaume Lemaitre <glemaitre>`.

imblearn/ensemble/_balance_cascade.py

@@ -12,6 +12,7 @@
 from sklearn.neighbors import KNeighborsClassifier
 from sklearn.utils import check_random_state, safe_indexing
 from sklearn.model_selection import cross_val_predict
+from sklearn.utils.deprecation import deprecated
 
 from .base import BaseEnsembleSampler
 from ..under_sampling.base import BaseUnderSampler
@@ -23,6 +24,7 @@
 @Substitution(
     sampling_strategy=BaseUnderSampler._sampling_strategy_docstring,
     random_state=_random_state_docstring)
+@deprecated('BalanceCascade is deprecated in 0.4 and will be removed in 0.6.')
 class BalanceCascade(BaseEnsembleSampler):
     """Create an ensemble of balanced sets by iteratively under-sampling the
     imbalanced dataset using an estimator.

imblearn/ensemble/tests/test_balance_cascade.py

@@ -5,6 +5,7 @@
 
 import numpy as np
 
+import pytest
 from pytest import raises
 
 from sklearn.utils.testing import assert_array_equal
@@ -30,6 +31,7 @@
 Y = np.array([0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0])
 
 
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 def test_fit_resample_auto():
     sampling_strategy = 'auto'
     bc = BalanceCascade(
@@ -68,6 +70,7 @@ def test_fit_resample_auto():
     assert_array_equal(idx_under, idx_gt)
 
 
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 def test_fit_resample_half():
     sampling_strategy = {0: 8, 1: 10}
     bc = BalanceCascade(
@@ -89,6 +92,7 @@ def test_fit_resample_half():
     assert_array_equal(y_resampled, y_gt)
 
 
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 def test_fit_resample_auto_early_stop():
     sampling_strategy = 'auto'
     estimator = LinearSVC(random_state=RND_SEED)
@@ -114,6 +118,7 @@ def test_fit_resample_auto_early_stop():
     assert_array_equal(y_resampled, y_gt)
 
 
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 def test_give_classifier_obj():
     sampling_strategy = 'auto'
     estimator = RandomForestClassifier(n_estimators=10, random_state=RND_SEED)
@@ -138,6 +143,7 @@ def test_give_classifier_obj():
     assert_array_equal(y_resampled, y_gt)
 
 
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 def test_give_classifier_wrong_obj():
     sampling_strategy = 'auto'
     classifier = 2

imblearn/tests/test_common.py

@@ -23,6 +23,7 @@ def test_all_estimator_no_base_class(name, Estimator):
 @pytest.mark.filterwarnings("ignore:'ratio' is deprecated from 0.4")
 @pytest.mark.filterwarnings("ignore:'sampling_strategy' as a dict for")
 @pytest.mark.filterwarnings("ignore:Class EasyEnsemble is deprecated")
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 @pytest.mark.filterwarnings('ignore:"kind" is deprecated in 0.4 and will be')
 @pytest.mark.filterwarnings('ignore:"svm_estimator" is deprecated in 0.4 and')
 @pytest.mark.filterwarnings('ignore:"out_step" is deprecated in 0.4 and')
@@ -55,6 +56,7 @@ def _generate_checks_per_estimator(check_generator, estimators):
 @pytest.mark.filterwarnings("ignore:'ratio' is deprecated from 0.4")
 @pytest.mark.filterwarnings("ignore:'sampling_strategy' as a dict for")
 @pytest.mark.filterwarnings("ignore:Class EasyEnsemble is deprecated")
+@pytest.mark.filterwarnings('ignore:Class BalanceCascade is deprecated')
 @pytest.mark.filterwarnings('ignore:"kind" is deprecated in 0.4 and will be')
 @pytest.mark.filterwarnings('ignore:"svm_estimator" is deprecated in 0.4 and')
 @pytest.mark.filterwarnings('ignore:"out_step" is deprecated in 0.4 and')