Make function _get_surrogate_model_replication_measure() public (#495)

Signed-off-by: Gaurav Gupta <gaugup@microsoft.com>

python/interpret_community/mimic/mimic_explainer.py

@@ -751,6 +751,10 @@ def __setstate__(self, state):
 
     def _get_surrogate_model_replication_measure(self, training_data):
         """Return the metric which tells how well the surrogate model replicates the teacher model.
+
+        For classification scenarios, this function will return accuracy. For regression scenarios,
+        this function will return r2_score.
+
         :param training_data: The data for getting the replication metric.
         :type training_data: numpy.array or pandas.DataFrame or scipy.sparse.csr_matrix
         :return: Metric that tells how well the surrogate model replicates the behavior of teacher model.
@@ -769,3 +773,16 @@ def _get_surrogate_model_replication_measure(self, training_data):
         else:
             replication_measure = r2_score(teacher_model_predictions, surrogate_model_predictions)
         return replication_measure
+
+    def get_surrogate_model_replication_measure(self, training_data):
+        """Return the metric which tells how well the surrogate model replicates the teacher model.
+
+        For classification scenarios, this function will return accuracy. For regression scenarios,
+        this function will return r2_score.
+
+        :param training_data: The data for getting the replication metric.
+        :type training_data: numpy.array or pandas.DataFrame or scipy.sparse.csr_matrix
+        :return: Metric that tells how well the surrogate model replicates the behavior of teacher model.
+        :rtype: float
+        """
+        return self._get_surrogate_model_replication_measure(training_data=training_data)

tests/test_mimic_explainer.py

@@ -412,7 +412,7 @@ def test_explain_raw_feats_regression(self, mimic_explainer):
     def _verify_predictions_and_replication_metric(self, mimic_explainer, data):
         predictions_main_model = mimic_explainer._get_teacher_model_predictions(data)
         predictions_surrogate_model = mimic_explainer._get_surrogate_model_predictions(data)
-        replication_score = mimic_explainer._get_surrogate_model_replication_measure(data)
+        replication_score = mimic_explainer.get_surrogate_model_replication_measure(data)
 
         assert predictions_main_model is not None
         assert predictions_surrogate_model is not None
@@ -422,8 +422,11 @@ def _verify_predictions_and_replication_metric(self, mimic_explainer, data):
         assert replication_score is not None and isinstance(replication_score, float)
 
         if mimic_explainer.classes is None:
-            with pytest.raises(ScenarioNotSupportedException):
-                mimic_explainer._get_surrogate_model_replication_measure(
+            with pytest.raises(
+                    ScenarioNotSupportedException,
+                    match="Replication measure for regression surrogate not supported "
+                          "because of single instance in training data"):
+                mimic_explainer.get_surrogate_model_replication_measure(
                     data[0].reshape(1, len(data[0])))
 
     def test_explain_model_string_classes(self, mimic_explainer):