Implement fit, transform

Signed-off-by: Sangmin Yoon <[email protected]>

aif360/algorithms/preprocessing/disparate_impact_remover.py

@@ -35,6 +35,49 @@ def __init__(self, repair_level=1.0, sensitive_attribute=''):
 
         self.sensitive_attribute = sensitive_attribute
 
+    def fit(self, dataset):
+        """Fit the model to the dataset.
+
+        Args:
+            dataset (BinaryLabelDataset): Dataset containing true labels and protected attributes.
+        Returns:
+            DisparateImpactRemover: Returns self after fitting the model.
+
+        Note:
+            This method sets the sensitive attribute if it is not already specified.
+        """
+        if not self.sensitive_attribute:
+            self.sensitive_attribute = dataset.protected_attribute_names[0]
+
+        return self
+
+    def transform(self, dataset):
+        """Transform the dataset using the fitted model.
+
+        Args:
+            dataset (BinaryLabelDataset): Dataset containing labels that needs to be transformed.
+        Returns:
+            BinaryLabelDataset: Transformed Dataset with adjusted feature values.
+
+        Note:
+            The transformation preserves the rank-ordering of features while modifying them
+            to reduce disparate impact based on the specified sensitive attribute.
+        """
+        features = dataset.features.tolist()
+        index = dataset.feature_names.index(self.sensitive_attribute)
+        repairer = self.Repairer(features, index, self.repair_level, False)
+
+        transformed_features = repairer.repair(features)
+        transformed_dataset = dataset.copy()
+        transformed_dataset.features = np.array(transformed_features, dtype=np.float64)
+
+        # Ensure protected attributes remain unchanged
+        transformed_dataset.features[:, index] = transformed_dataset.protected_attributes[:,
+                                                 transformed_dataset.protected_attribute_names.index(
+                                                     self.sensitive_attribute)]
+
+        return transformed_dataset
+
     def fit_transform(self, dataset):
         """Run a repairer on the non-protected features and return the
         transformed dataset.