Lava Gap#


Action Space	`Discrete(7)`
Observation Space	`Dict('direction': Discrete(4), 'image': Box(0, 255, (7, 7, 3), uint8), 'mission': MissionSpace(<function LavaGapEnv._gen_mission_lava at 0x7f813f507d30>, None))`
Reward Range	`(0, 1)`
Creation	`gymnasium.make("MiniGrid-LavaGapS7-v0")`

Description#

The agent has to reach the green goal square at the opposite corner of the room, and must pass through a narrow gap in a vertical strip of deadly lava. Touching the lava terminate the episode with a zero reward. This environment is useful for studying safety and safe exploration.

Mission Space#

Depending on the obstacle_type parameter:

Lava: “avoid the lava and get to the green goal square”
otherwise: “find the opening and get to the green goal square”

Action Space#

Num	Name	Action
0	left	Turn left
1	right	Turn right
2	forward	Move forward
3	pickup	Unused
4	drop	Unused
5	toggle	Unused
6	done	Unused

Observation Encoding#

Each tile is encoded as a 3 dimensional tuple: (OBJECT_IDX, COLOR_IDX, STATE)
OBJECT_TO_IDX and COLOR_TO_IDX mapping can be found in minigrid/core/constants.py
STATE refers to the door state with 0=open, 1=closed and 2=locked

Rewards#

A reward of ‘1 - 0.9 * (step_count / max_steps)’ is given for success, and ‘0’ for failure.

Termination#

The episode ends if any one of the following conditions is met:

The agent reaches the goal.
The agent falls into lava.
Timeout (see max_steps).

Registered Configurations#

S: size of map SxS.

MiniGrid-LavaGapS5-v0
MiniGrid-LavaGapS6-v0
MiniGrid-LavaGapS7-v0