added get_many() method to observation builders, base class and derived. Also...

added get_many() method to observation builders, base class and derived. Also removed the render() methods in the env base class and railenv

flatland/core/env.py

@@ -99,12 +99,6 @@ class Environment:
         """
         raise NotImplementedError()
 
-    def render(self):
-        """
-        Perform rendering of the environment.
-        """
-        raise NotImplementedError()
-
     def get_agent_handles(self):
         """
         Returns a list of agents' handles to be used as keys in the step()

flatland/core/env_observation_builder.py

@@ -30,6 +30,27 @@ class ObservationBuilder:
         """
         raise NotImplementedError()
 
+    def get_many(self, handles=[]):
+        """
+        Called whenever an observation has to be computed for the `env' environment, for each agent with handle
+        in the `handles' list.
+
+        Parameters
+        -------
+        handles : list of handles (optional)
+            List with the handles of the agents for which to compute the observation vector.
+
+        Returns
+        -------
+        function
+            A dictionary of observation structures, specific to the corresponding environment, with handles from
+            `handles' as keys.
+        """
+        observations = {}
+        for h in handles:
+            observations[h] = self.get(h)
+        return observations
+
     def get(self, handle=0):
         """
         Called whenever an observation has to be computed for the `env' environment, possibly

flatland/envs/observations.py

@@ -167,6 +167,19 @@ class TreeObsForRailEnv(ObservationBuilder):
         elif movement == 3:  # WEST
             return (position[0], position[1] - 1)
 
+    def get_many(self, handles=[]):
+        """
+        Called whenever an observation has to be computed for the `env' environment, for each agent with handle
+        in the `handles' list.
+        """
+
+        # TODO: @Erik this is where the predictions should be computed, storing any temporary data inside this object.
+
+        observations = {}
+        for h in handles:
+            observations[h] = self.get(h)
+        return observations
+
     def get(self, handle):
         """
         Computes the current observation for agent `handle' in env

flatland/envs/rail_env.py

@@ -330,10 +330,7 @@ class RailEnv(Environment):
         return new_direction, transition_isValid
 
     def _get_observations(self):
-        self.obs_dict = {}
-        self.debug_obs_dict = {}
-        for iAgent in range(self.get_num_agents()):
-            self.obs_dict[iAgent] = self.obs_builder.get(iAgent)
+        self.obs_dict = self.obs_builder.get_many(list(range(self.get_num_agents())))
         return self.obs_dict
 
     def _get_predictions(self):
@@ -341,10 +338,6 @@ class RailEnv(Environment):
             return {}
         return {}
 
-    def render(self):
-        # TODO:
-        pass
-
     def get_full_state_msg(self):
         grid_data = self.rail.grid.tolist()
         agent_static_data = [agent.to_list() for agent in self.agents_static]