update

facility_location/env/obs_extractor.py

@@ -117,20 +117,21 @@ class ObsExtractor:
         return obs
 
     def _get_obs_graph(self) -> Tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
+        EPS = 1e-8
         facility = self._flc.get_current_solution().astype(np.float32)
         distance = self._flc.get_current_distance().astype(np.float32)
         distance = distance / np.max(distance)
         cost = self._flc.get_current_cost().astype(np.float32)
         cost = cost / np.max(cost)
         gain, loss = self._flc.get_gain_and_loss()
-        gain = gain / np.max(gain)
-        loss = loss / np.max(loss)
+        gain = gain / (np.max(gain) + EPS)
+        loss = loss / (np.max(loss) + EPS)
         dynamic_node_features = np.stack([
             facility,
             distance[:,0],
             distance[:,1],
             cost[:,0],
-            cost[:,1],
+            cost[:,1], 
             gain,
             loss,
         ], axis=-1)