LocalOutlierFactor implementation (#990)

* add LocalOutlierFactor wrapper

* Tests for LocalOutlierFactor

---------

Co-authored-by: Vladislav Nazarov <[email protected]>
Co-authored-by: Alexander Andreev <[email protected]>

Author: 3 people

deselected_tests.yaml

@@ -39,6 +39,8 @@ deselected_tests:
   - linear_model/tests/test_logistic.py::test_logistic_regression_multinomial
   - neighbors/tests/test_neighbors.py::test_neigh_predictions_algorithm_agnosticity[float64-KNeighborsClassifier-1-100-minkowski-1000-5-100]
   - cluster/tests/test_k_means.py::test_k_means_fit_predict >=0.23,<0.24
+  - neighbors/tests/test_lof.py::test_lof_dtype_equivalence[0.5-True-brute]
+  - neighbors/tests/test_lof.py::test_lof_dtype_equivalence[auto-True-brute]
 
   # cache directory is not accessible on some systems
   - utils/tests/test_validation.py::test_check_memory

sklearnex/dispatcher.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-# ===============================================================================
+#===============================================================================
 # Copyright 2021 Intel Corporation
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -51,6 +51,7 @@ def get_patch_map():
         from .neighbors import KNeighborsClassifier as KNeighborsClassifier_sklearnex
         from .neighbors import KNeighborsRegressor as KNeighborsRegressor_sklearnex
         from .neighbors import NearestNeighbors as NearestNeighbors_sklearnex
+        from .neighbors import LocalOutlierFactor as LocalOutlierFactor_sklearnex
 
         # Preview classes for patching
 
@@ -130,6 +131,12 @@ def get_patch_map():
         mapping['kneighborsregressor'] = mapping['knn_regressor']
         mapping['nearestneighbors'] = mapping['nearest_neighbors']
 
+        # LocalOutlierFactor
+        mapping['lof'] = [[(neighbors_module,
+                            'LocalOutlierFactor',
+                            LocalOutlierFactor_sklearnex), None]]
+        mapping['localoutlierfactor'] = mapping['lof']
+
         # Configs
         mapping['set_config'] = [[(base_module,
                                    'set_config',

sklearnex/neighbors/__init__.py

@@ -18,5 +18,7 @@
 from .knn_classification import KNeighborsClassifier
 from .knn_unsupervised import NearestNeighbors
 from .knn_regression import KNeighborsRegressor
+from .lof import LocalOutlierFactor
 
-__all__ = ['KNeighborsClassifier', 'KNeighborsRegressor', 'NearestNeighbors']
+__all__ = ['KNeighborsClassifier', 'KNeighborsRegressor', 'LocalOutlierFactor',
+           'NearestNeighbors']

sklearnex/neighbors/knn_unsupervised.py

@@ -199,7 +199,7 @@ def fit(self, X, y=None):
     @wrap_output_data
     def kneighbors(self, X=None, n_neighbors=None, return_distance=True):
         check_is_fitted(self)
-        if sklearn_check_version("1.0"):
+        if sklearn_check_version("1.0") and X is not None:
             self._check_feature_names(X, reset=False)
         return dispatch(self, 'neighbors.NearestNeighbors.kneighbors', {
             'onedal': self.__class__._onedal_kneighbors,