def _shortest_path()

in data/envs/babyai/bot_agent.py [0:0]

• 21 lines of code
• 8 McCabe index (conditional complexity)

    def _shortest_path(self, accept_fn, try_with_blockers=False):
        """
        Finds the path to any of the locations that satisfy `accept_fn`.
        Prefers the paths that avoid blockers for as long as possible.
        """

        # Initial states to visit (BFS)
        initial_states = [(*self.mission.unwrapped.agent_pos, *self.mission.unwrapped.dir_vec)]

        path = finish = None
        with_blockers = False
        path, finish, previous_pos = self._breadth_first_search(initial_states, accept_fn, ignore_blockers=False)
        if not path and try_with_blockers:
            with_blockers = True
            path, finish, _ = self._breadth_first_search(
                [(i, j, 1, 0) for i, j in previous_pos], accept_fn, ignore_blockers=True
            )
            if path:
                # `path` now contains the path to a cell that is reachable without
                # blockers. Now let's add the path to this cell
                pos = path[-1]
                extra_path = []
                while pos:
                    extra_path.append(pos)
                    pos = previous_pos[pos]
                path = path + extra_path[1:]

        if path:
            # And the starting position is not required
            path = path[::-1]
            path = path[1:]

        # Note, that with_blockers only makes sense if path is not None
        return path, finish, with_blockers