FastTreeObs (fix) -> 0.8157

utils/fast_tree_obs.py

@@ -207,8 +207,10 @@ class FastTreeObs(ObservationBuilder):
             possible_transitions = self.env.rail.get_transitions(*new_position, new_direction)
             if agents_on_switch:
                 orientation = new_direction
-                if fast_count_nonzero(possible_transitions) == 1:
+                possible_transitions_nonzero = fast_count_nonzero(possible_transitions)
+                if possible_transitions_nonzero == 1:
                     orientation = fast_argmax(possible_transitions)
+
                 for dir_loop, branch_direction in enumerate(
                         [(orientation + dir_loop) % 4 for dir_loop in range(-1, 3)]):
                     # branch the exploration path and aggregate the found information