From 8176e2fe7fc6b492576bd1946a3897a626918ed2 Mon Sep 17 00:00:00 2001
From: Erik Nygren <erik.nygren@sbb.ch>
Date: Wed, 3 Jul 2019 16:14:41 -0400
Subject: [PATCH] updated comment to make tree observation more understandable
---
examples/training_example.py | 2 +
flatland/envs/observations.py | 79 +++++++++++++++++++++--------------
flatland/utils/rendertools.py | 2 +-
3 files changed, 51 insertions(+), 32 deletions(-)
diff --git a/examples/training_example.py b/examples/training_example.py
index dd9ded92..cdbd1ade 100644
--- a/examples/training_example.py
+++ b/examples/training_example.py
@@ -76,6 +76,8 @@ for trials in range(1, n_trials + 1):
for a in range(env.get_num_agents()):
action = agent.act(obs[a])
action_dict.update({a: action})
+ # Uncomment next line to print observation of an agent
+ # TreeObservation.util_print_obs_subtree((obs[a]))
# Environment step which returns the observations for all agents, their corresponding
# reward and whether their are done
diff --git a/flatland/envs/observations.py b/flatland/envs/observations.py
index 8ed455ca..8222115e 100644
--- a/flatland/envs/observations.py
+++ b/flatland/envs/observations.py
@@ -28,7 +28,7 @@ class TreeObsForRailEnv(ObservationBuilder):
for i in range(self.max_depth + 1):
size += pow4
pow4 *= 4
- self.observation_dim = 8
+ self.observation_dim = 9
self.observation_space = [size * self.observation_dim]
self.location_has_agent = {}
self.location_has_agent_direction = {}
@@ -223,24 +223,29 @@ class TreeObsForRailEnv(ObservationBuilder):
#3: if another agent is detected the distance in number of cells from current agent position is stored.
- #4: This feature stores the distance in number of cells to the next branching store (current node)
+ #4: possible conflict detected
+ tot_dist = Other agent predicts to pass along this cell at the same time as the agent, we store the
+ distance in number of cells from current agent position
- #5: minimum distance from node to the agent's target given the direction of the agent if this path is chosen
+ 0 = No other agent reserve the same cell at similar time
+
+ #5: if an not usable switch (for agent) is detected we store the distance.
+
+ #6: This feature stores the distance in number of cells to the next branching (current node)
+
+ #7: minimum distance from node to the agent's target given the direction of the agent if this path is chosen
- #6: agent in the same direction
+ #8: agent in the same direction
n = number of agents present same direction
(possible future use: number of other agents in the same direction in this branch)
0 = no agent present same direction
- #7: agent in the opposite drection
+ #9: agent in the opposite drection
n = number of agents present other direction than myself (so conflict)
(possible future use: number of other agents in other direction in this branch, ie. number of conflicts)
0 = no agent present other direction than myself
- #8: possible conflict detected
- 1 = Other agent predicts to pass along this cell at the same time as the agent
- 0 = No other agent reserve the same cell at similar time
Missing/padding nodes are filled in with -inf (truncated).
@@ -261,7 +266,7 @@ class TreeObsForRailEnv(ObservationBuilder):
num_transitions = np.count_nonzero(possible_transitions)
# Root node - current position
- observation = [0, 0, 0, 0, self.distance_map[(handle, *agent.position, agent.direction)], 0, 0, 0]
+ observation = [0, 0, 0, 0, 0, 0, self.distance_map[(handle, *agent.position, agent.direction)], 0, 0]
root_observation = observation[:]
visited = set()
@@ -294,6 +299,8 @@ class TreeObsForRailEnv(ObservationBuilder):
def _explore_branch(self, handle, position, direction, root_observation, tot_dist, depth):
"""
Utility function to compute tree-based observations.
+ We walk along the branch and collect the information documented in the get() function.
+ If there is a branching point a new node is created and each possible branch is explored.
"""
# [Recursive branch opened]
if depth >= self.max_depth + 1:
@@ -313,9 +320,11 @@ class TreeObsForRailEnv(ObservationBuilder):
own_target_encountered = np.inf
other_agent_encountered = np.inf
other_target_encountered = np.inf
+ potential_conflict = np.inf
+ unusable_switch = np.inf
other_agent_same_direction = 0
other_agent_opposite_direction = 0
- potential_conflict = 0
+
num_steps = 1
while exploring:
# #############################
@@ -323,8 +332,8 @@ class TreeObsForRailEnv(ObservationBuilder):
# Modify here to compute any useful data required to build the end node's features. This code is called
# for each cell visited between the previous branching node and the next switch / target / dead-end.
if position in self.location_has_agent:
- if num_steps < other_agent_encountered:
- other_agent_encountered = num_steps
+ if tot_dist < other_agent_encountered:
+ other_agent_encountered = tot_dist
if self.location_has_agent_direction[position] == direction:
# Cummulate the number of agents on branch with same direction
@@ -345,28 +354,28 @@ class TreeObsForRailEnv(ObservationBuilder):
if int_position in np.delete(self.predicted_pos[tot_dist], handle):
conflicting_agent = np.where(np.delete(self.predicted_pos[tot_dist], handle) == int_position)
for ca in conflicting_agent:
- if direction != self.predicted_dir[tot_dist][ca[0]]:
- potential_conflict = 1
+ if direction != self.predicted_dir[tot_dist][ca[0]] and tot_dist < potential_conflict:
+ potential_conflict = tot_dist
# Look for opposing paths at distance num_step-1
elif int_position in np.delete(self.predicted_pos[pre_step], handle):
conflicting_agent = np.where(self.predicted_pos[pre_step] == int_position)
for ca in conflicting_agent:
- if direction != self.predicted_dir[pre_step][ca[0]]:
- potential_conflict = 1
+ if direction != self.predicted_dir[pre_step][ca[0]] and tot_dist < potential_conflict:
+ potential_conflict = tot_dist
# Look for opposing paths at distance num_step+1
elif int_position in np.delete(self.predicted_pos[post_step], handle):
conflicting_agent = np.where(np.delete(self.predicted_pos[post_step], handle) == int_position)
for ca in conflicting_agent:
- if direction != self.predicted_dir[post_step][ca[0]]:
- potential_conflict = 1
+ if direction != self.predicted_dir[post_step][ca[0]] and tot_dist < potential_conflict:
+ potential_conflict = tot_dist
if position in self.location_has_target and position != agent.target:
- if num_steps < other_target_encountered:
- other_target_encountered = num_steps
+ if tot_dist < other_target_encountered:
+ other_target_encountered = tot_dist
if position == agent.target:
- if num_steps < own_target_encountered:
- own_target_encountered = num_steps
+ if tot_dist < own_target_encountered:
+ own_target_encountered = tot_dist
# #############################
# #############################
@@ -382,8 +391,13 @@ class TreeObsForRailEnv(ObservationBuilder):
break
cell_transitions = self.env.rail.get_transitions((*position, direction))
+ total_transitions = bin(self.env.rail.get_transitions(position)).count("1")
num_transitions = np.count_nonzero(cell_transitions)
exploring = False
+ # Detect Switches that can only be used by other agents.
+ if total_transitions > 2 > num_transitions:
+ unusable_switch = tot_dist
+
if num_transitions == 1:
# Check if dead-end, or if we can go forward along direction
nbits = 0
@@ -462,32 +476,35 @@ class TreeObsForRailEnv(ObservationBuilder):
observation = [own_target_encountered,
other_target_encountered,
other_agent_encountered,
- root_observation[3] + num_steps,
+ potential_conflict,
+ unusable_switch,
+ tot_dist,
0,
other_agent_same_direction,
- other_agent_opposite_direction,
- potential_conflict
+ other_agent_opposite_direction
]
elif last_isTerminal:
observation = [own_target_encountered,
other_target_encountered,
other_agent_encountered,
+ potential_conflict,
+ unusable_switch,
np.inf,
- np.inf,
+ self.distance_map[handle, position[0], position[1], direction],
other_agent_same_direction,
- other_agent_opposite_direction,
- potential_conflict
+ other_agent_opposite_direction
]
else:
observation = [own_target_encountered,
other_target_encountered,
other_agent_encountered,
- root_observation[3] + num_steps,
+ potential_conflict,
+ unusable_switch,
+ tot_dist,
self.distance_map[handle, position[0], position[1], direction],
other_agent_same_direction,
other_agent_opposite_direction,
- potential_conflict
]
# #############################
# #############################
@@ -531,7 +548,7 @@ class TreeObsForRailEnv(ObservationBuilder):
return observation, visited
- def util_print_obs_subtree(self, tree, num_features_per_node=8, prompt='', current_depth=0):
+ def util_print_obs_subtree(self, tree, num_features_per_node=9, prompt='', current_depth=0):
"""
Utility function to pretty-print tree observations returned by this object.
"""
diff --git a/flatland/utils/rendertools.py b/flatland/utils/rendertools.py
index 7932aaca..537d8be8 100644
--- a/flatland/utils/rendertools.py
+++ b/flatland/utils/rendertools.py
@@ -38,7 +38,7 @@ class RenderTool(object):
gTheta = np.linspace(0, np.pi / 2, 5)
gArc = array([np.cos(gTheta), np.sin(gTheta)]).T # from [1,0] to [0,1]
- def __init__(self, env, gl="PILSVG", jupyter=False, agentRenderVariant=AgentRenderVariant.AGENT_SHOWS_OPTIONS):
+ def __init__(self, env, gl="PILSVG", jupyter=False, agentRenderVariant=AgentRenderVariant.ONE_STEP_BEHIND):
self.env = env
self.iFrame = 0
self.time1 = time.time()
--
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