flatland.envs.rail_grid_transition_map module

flatland.envs.rail_grid_transition_map module#

class flatland.envs.rail_grid_transition_map.RailGridTransitionMap(width, height, transitions: ~flatland.core.transitions.Transitions = <flatland.core.grid.rail_env_grid.RailEnvTransitions object>, random_seed=None, grid: ~numpy.ndarray | None = None)[source]#

Bases: GridTransitionMap

check_action_on_agent(action: RailEnvActions, position: Tuple[int, int], direction: Grid4TransitionsEnum)[source]#

Apply the action on the train regardless of locations of other trains. Checks for valid cells to move and valid rail transitions.

Parameters#

actionRailEnvActions

Action to execute

positionIntVector2D

current position of the train

directionGrid4TransitionsEnum

current direction of the train

Returns#

new_cell_valid: bool

is the new position and direction valid (i.e. is it within bounds and does it have > 0 outgoing transitions)

new_position

New position after applying the action

new_direction

New direction after applying the action

transition_valid: bool

Whether the transition from old and direction is defined in the grid. In other words, can the action be applied directly? False if - MOVE_FORWARD/DO_NOTHING when entering symmetric switch - MOVE_LEFT/MOVE_RIGHT corrected to MOVE_FORWARD in switches and dead-ends However, transition_valid for dead-ends and turns either with the correct MOVE_RIGHT/MOVE_LEFT or MOVE_FORWARD/DO_NOTHING.

preprocessed_action: RailEnvActions

Corrected action if not transition_valid.

The preprocessed action has the following semantics: - MOVE_LEFT/MOVE_RIGHT: turn left/right without acceleration - MOVE_FORWARD: move forward with acceleration (swap direction in dead-end, also works in left/right turns or symmetric-switches non-facing) - DO_NOTHING: if already moving, keep moving forward without acceleration (swap direction in dead-end, also works in left/right turns or symmetric-switches non-facing); if stopped, stay stopped.

check_bounds(position)[source]#
get_valid_move_actions_(agent_direction: Grid4TransitionsEnum, agent_position: Tuple[int, int]) → Set[RailEnvNextAction][source]#

Get the valid move actions (forward, left, right) for an agent.

TODO The implementation could probably be more efficient and more elegant,

but given the few calls this has no priority now.

Parameters#

agent_direction : Grid4TransitionsEnum agent_position: Tuple[int,int]

Returns#

Set of RailEnvNextAction (tuples of (action,position,direction))

Possible move actions (forward,left,right) and the next position/direction they lead to. It is not checked that the next cell is free.

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