multi speed implementation + a bit of step() refactoring

flatland/envs/agent_utils.py

@@ -28,10 +28,13 @@ class EnvAgentStatic(object):
     position = attrib()
     direction = attrib()
     target = attrib()
-    moving = attrib()
-    speed_data = attrib(default=dict({'position_fraction':0.0, 'speed':1.0, 'transition_action_on_cellexit':0}))
+    moving = attrib(default=False)
+    # speed_data: speed is added to position_fraction on each moving step, until position_fraction>=1.0,
+    # after which 'transition_action_on_cellexit' is executed (equivalent to executing that action in the previous
+    # cell if speed=1, as default)
+    speed_data = attrib(default=dict({'position_fraction': 0.0, 'speed': 1.0, 'transition_action_on_cellexit': 0}))
 
-    def __init__(self, position, direction, target, moving=False, speed_data={'position_fraction':0.0, 'speed':1.0, 'transition_action_on_cellexit':0}):
+    def __init__(self, position, direction, target, moving=False, speed_data={'position_fraction': 0.0, 'speed': 1.0, 'transition_action_on_cellexit': 0}):
         self.position = position
         self.direction = direction
         self.target = target
@@ -44,7 +47,7 @@ class EnvAgentStatic(object):
         """
         speed_datas = []
         for i in range(len(positions)):
-            speed_datas.append( {'position_fraction':0.0, 'speed':1.0, 'transition_action_on_cellexit':0} )
+            speed_datas.append( {'position_fraction': 0.0, 'speed': 1.0, 'transition_action_on_cellexit': 0} )
         return list(starmap(EnvAgentStatic, zip(positions, directions, targets, [False] * len(positions), speed_datas)))
 
     def to_list(self):

flatland/envs/rail_env.py

@@ -101,7 +101,6 @@ class RailEnv(Environment):
         self.action_space = [1]
         self.observation_space = self.obs_builder.observation_space  # updated on resets?
 
-        self.actions = [0] * number_of_agents
         self.rewards = [0] * number_of_agents
         self.done = False
 
@@ -193,22 +192,24 @@ class RailEnv(Environment):
         for iAgent in range(self.get_num_agents()):
             agent = self.agents[iAgent]
 
-            if iAgent not in action_dict:  # no action has been supplied for this agent
-                if agent.moving:
-                    # Keep moving
-                    # Change MOVE_FORWARD to DO_NOTHING
-                    action_dict[iAgent] = RailEnvActions.DO_NOTHING
-                else:
-                    action_dict[iAgent] = RailEnvActions.DO_NOTHING
-
             if self.dones[iAgent]:  # this agent has already completed...
                 continue
-            action = action_dict[iAgent]
 
-            if action < 0 or action > len(RailEnvActions):
-                print('ERROR: illegal action=', action,
-                      'for agent with index=', iAgent)
-                return
+            if np.equal(agent.position, agent.target).all():
+                self.dones[iAgent] = True
+            else:
+                self.rewards_dict[iAgent] += step_penalty
+
+            if iAgent not in action_dict:  # no action has been supplied for this agent
+                action_dict[iAgent] = RailEnvActions.DO_NOTHING
+
+            if action_dict[iAgent] < 0 or action_dict[iAgent] > len(RailEnvActions):
+                print('ERROR: illegal action=', action_dict[iAgent],
+                      'for agent with index=', iAgent,
+                      '"DO NOTHING" will be executed instead')
+                action_dict[iAgent] = RailEnvActions.DO_NOTHING
+
+            action = action_dict[iAgent]
 
             if action == RailEnvActions.DO_NOTHING and agent.moving:
                 # Keep moving
@@ -224,46 +225,60 @@ class RailEnv(Environment):
                 self.rewards_dict[iAgent] += start_penalty
 
             if action != RailEnvActions.DO_NOTHING and action != RailEnvActions.STOP_MOVING:
-                cell_isFree, new_cell_isValid, new_direction, new_position, transition_isValid = \
-                    self._check_action_on_agent(action, agent)
-                if all([new_cell_isValid, transition_isValid, cell_isFree]):
-                    agent.old_direction = agent.direction
-                    agent.old_position = agent.position
-                    agent.position = new_position
-                    agent.direction = new_direction
-                else:
-                    # Logic: if the chosen action is invalid,
-                    # and it was LEFT or RIGHT, and the agent was moving, then keep moving FORWARD.
-                    if (action == RailEnvActions.MOVE_LEFT or action == RailEnvActions.MOVE_RIGHT) and agent.moving:
-                        cell_isFree, new_cell_isValid, new_direction, new_position, transition_isValid = \
-                            self._check_action_on_agent(RailEnvActions.MOVE_FORWARD, agent)
-
-                        if all([new_cell_isValid, transition_isValid, cell_isFree]):
-                            agent.old_direction = agent.direction
-                            agent.old_position = agent.position
-                            agent.position = new_position
-                            agent.direction = new_direction
+                # Now perform a movement.
+                # If the agent is in an initial position within a new cell (agent.speed_data['position_fraction']<eps)
+                #       store the desired action in `transition_action_on_cellexit' (only if the desired transition is allowed! otherwise DO_NOTHING!)
+                # Then in any case (if agent.moving) and the `transition_action_on_cellexit' is valid, increment the position_fraction by the speed of the agent   (regardless of action taken, as long as no STOP_MOVING, but that makes agent.moving=False)
+                # If the new position fraction is >= 1, reset to 0, and perform the stored transition_action_on_cellexit
+
+                if agent.speed_data['position_fraction'] < 0.01:
+                    # Is the desired transition valid?
+
+                    cell_isFree, new_cell_isValid, new_direction, new_position, transition_isValid = \
+                        self._check_action_on_agent(action, agent)
+
+                    if all([new_cell_isValid, transition_isValid, cell_isFree]):
+                        agent.speed_data['transition_action_on_cellexit'] = action
+
+                    else:
+                        # But, if the chosen invalid action was LEFT/RIGHT, and the agent is moving,
+                        # try to keep moving forward!
+                        if (action == RailEnvActions.MOVE_LEFT or action == RailEnvActions.MOVE_RIGHT) and agent.moving:
+                            cell_isFree, new_cell_isValid, new_direction, new_position, transition_isValid = \
+                                self._check_action_on_agent(RailEnvActions.MOVE_FORWARD, agent)
+
+                            if all([new_cell_isValid, transition_isValid, cell_isFree]):
+                                agent.speed_data['transition_action_on_cellexit'] = RailEnvActions.MOVE_FORWARD
+
+                            else:
+                                # TODO: an invalid action was chosen after entering the cell. The agent cannot move.
+                                self.rewards_dict[iAgent] += invalid_action_penalty
+                                continue
                         else:
-                            # the action was not valid, add penalty
+                            # TODO: an invalid action was chosen after entering the cell. The agent cannot move.
                             self.rewards_dict[iAgent] += invalid_action_penalty
+                            continue
 
-                    else:
-                        # the action was not valid, add penalty
-                        self.rewards_dict[iAgent] += invalid_action_penalty
+                agent.speed_data['position_fraction'] += agent.speed_data['speed']
 
-            if np.equal(agent.position, agent.target).all():
-                self.dones[iAgent] = True
-            else:
-                self.rewards_dict[iAgent] += step_penalty
+                if agent.speed_data['position_fraction'] >= 1.0:
+                    agent.speed_data['position_fraction'] = 0.0
+
+                    # Perform stored action to transition to the next cell
+
+                    # Now 'transition_action_on_cellexit' will be guaranteed to be valid; it was checked on entering the cell
+                    cell_isFree, new_cell_isValid, new_direction, new_position, transition_isValid = \
+                        self._check_action_on_agent(agent.speed_data['transition_action_on_cellexit'], agent)
+                    agent.old_direction = agent.direction
+                    agent.old_position = agent.position
+                    agent.position = new_position
+                    agent.direction = new_direction
 
         # Check for end of episode + add global reward to all rewards!
         if np.all([np.array_equal(agent2.position, agent2.target) for agent2 in self.agents]):
             self.dones["__all__"] = True
             self.rewards_dict = [0 * r + global_reward for r in self.rewards_dict]
 
-        # Reset the step actions (in case some agent doesn't 'register_action'
-        # on the next step)
-        self.actions = [0] * self.get_num_agents()
         return self._get_observations(), self.rewards_dict, self.dones, {}
 
     def _check_action_on_agent(self, action, agent):
@@ -271,6 +286,7 @@ class RailEnv(Environment):
         # cell used to check for invalid actions
         new_direction, transition_isValid = self.check_action(agent, action)
         new_position = get_new_position(agent.position, new_direction)
+
         # Is it a legal move?
         # 1) transition allows the new_direction in the cell,
         # 2) the new cell is not empty (case 0),
@@ -281,11 +297,13 @@ class RailEnv(Environment):
                 np.clip(new_position, [0, 0], [self.height - 1, self.width - 1]))
             and  # check the new position has some transitions (ie is not an empty cell)
             self.rail.get_transitions(new_position) > 0)
+
         # If transition validity hasn't been checked yet.
         if transition_isValid is None:
             transition_isValid = self.rail.get_transition(
                 (*agent.position, agent.direction),
                 new_direction)
+
         # Check the new position is not the same as any of the existing agent positions
         # (including itself, for simplicity, since it is moving)
         cell_isFree = not np.any(