`prepare()` and `resume()` perform duplicate computation

[NONONOexe]

While developing based on sample_road_detector.py, we noticed that prepare() and resume() perform the same computation. We believe this calculation should be performed by precompute(), not resume().

 def resume(self, precompute_data: PrecomputeData) -> RoadDetector:
 super().resume(precompute_data)
 if self.get_count_resume() >= 2:
 return self

 self._target_areas: set[EntityID] = set()
 entities = self._world_info.get_entities_of_types([Refuge, Building, GasStation])
 for entity in entities:
 if not isinstance(entity, Building):
 continue
 for entity_id in entity.get_neighbors():
 neighbor = self._world_info.get_entity(entity_id)
 if isinstance(neighbor, Road):
 self._target_areas.add(entity_id)

 self._priority_roads = set()
 for entity in self._world_info.get_entities_of_types([Refuge]):
 if not isinstance(entity, Building):
 continue
 for entity_id in entity.get_neighbors():
 neighbor = self._world_info.get_entity(entity_id)
 if isinstance(neighbor, Road):
 self._priority_roads.add(entity_id)

 return self

 def prepare(self) -> RoadDetector:
 super().prepare()
 if self.get_count_prepare() >= 2:
 return self

 self._target_areas = set()
 entities = self._world_info.get_entities_of_types([Refuge, Building, GasStation])
 for entity in entities:
 building: Building = cast(Building, entity)
 for entity_id in building.get_neighbors():
 neighbor = self._world_info.get_entity(entity_id)
 if isinstance(neighbor, Road):
 self._target_areas.add(entity_id)

 self._priority_roads = set()
 for entity in self._world_info.get_entities_of_types([Refuge]):
 refuge: Refuge = cast(Refuge, entity)
 for entity_id in refuge.get_neighbors():
 neighbor = self._world_info.get_entity(entity_id)
 if isinstance(neighbor, Road):
 self._priority_roads.add(entity_id)

 return self

[NONONOexe]

I had mistakenly written precompute() and prepare() in the the explanation, so I have rewrited them.

[NONONOexe]

I think there may be a cleaner way to express this, but here is my attempt at organizing it. This is what I believe that the code should look like when precompute() is used correctly.

...

 def precompute(self, precompute_data: PrecomputeData) -> RoadDetector:
 super().precompute(precompute_data)

 target_areas = self._init_target_areas()
 priority_roads = self._build_priority_roads()

 precompute_data.write_json_data(
 {
 "target_areas": list(target_areas),
 "priority_roads": list(priority_roads)
 },
 "RoadDetector"
 )

 return self

 def resume(self, precompute_data: PrecomputeData) -> RoadDetector:
 super().resume(precompute_data)

 if 1 < self.get_count_resume():
 return self

 data = precompute_data.read_json_data("RoadDetector")
 self._target_areas = data["target_areas"]
 self._priority_roads = frozenset(data["priority_roads"])

 return self

 def prepare(self) -> RoadDetector:
 super().prepare()
 if 1 < self.get_count_prepare():
 return self

 self._target_areas = self._init_target_areas()
 self._priority_roads = self._build_priority_roads()

 return self
 
 def _init_target_areas(self) -> set[EntityID]:
 """Initialize a set of roads adjacent to buildings, refuges, and gas stations."""
 return set(
 entity_id
 for entity in self._world_info.get_entities_of_types([Refuge, Building, GasStation])
 if isinstance(entity, Building)
 for entity_id in entity.get_neighbors()
 if isinstance(self._world_info.get_entity(entity_id), Road)
 )

 def _build_priority_roads(self) -> frozenset[EntityID]:
 """Build an immutable set of roads adjacent to refuges."""
 return frozenset(
 entity_id
 for entity in self._world_info.get_entities_of_types([Refuge])
 if isinstance(entity, Refuge)
 for entity_id in entity.get_neighbors()
 if isinstance(self._world_info.get_entity(entity_id), Road)
 )

...

[ToB213]

I found a similar issue in KMeansClustering. Both precompute() and prepare() call create_cluster(), resulting in the same clustering computation being performed twice.

def precompute(self, precompute_data):
 cluster_entities = self.create_cluster(...) # computed here
 precompute_data.write_json_data(...)

def prepare(self):
 self.cluster_entities = self.create_cluster(...) # same computation repeated

As with your proposed fix, I think the solution is to extract create_cluster() as a helper method and call it from both precompute() and prepare().