YarsRevenge

../../_images/yars_revenge.gif

This environment is part of the Atari environments. Please read that page first for general information.

Action Space

Discrete(18)

Observation Space

Box(0, 255, (210, 160, 3), uint8)

Import

gymnasium.make("ALE/YarsRevenge-v5")

For more YarsRevenge variants with different observation and action spaces, see the variants section.

Description

The objective is to break a path through the shield and destroy the Qotile with a blast from the Zorlon Cannon.

For a more detailed documentation, see the AtariAge page

Actions

YarsRevenge has the action space Discrete(18) with the table below listing the meaning of each action’s meanings. As YarsRevenge uses the full set of actions then specifying full_action_space=True will not modify the action space of the environment if passed to gymnasium.make.

Value

Meaning

Value

Meaning

Value

Meaning

0

NOOP

1

FIRE

2

UP

3

RIGHT

4

LEFT

5

DOWN

6

UPRIGHT

7

UPLEFT

8

DOWNRIGHT

9

DOWNLEFT

10

UPFIRE

11

RIGHTFIRE

12

LEFTFIRE

13

DOWNFIRE

14

UPRIGHTFIRE

15

UPLEFTFIRE

16

DOWNRIGHTFIRE

17

DOWNLEFTFIRE

See environment specification to see more information on the action meaning.

Observations

Atari environments have three possible observation types: "rgb", "grayscale" and "ram".

  • obs_type="rgb" -> observation_space=Box(0, 255, (210, 160, 3), np.uint8)

  • obs_type="ram" -> observation_space=Box(0, 255, (128,), np.uint8)

  • obs_type="grayscale" -> Box(0, 255, (210, 160), np.uint8), a grayscale version of the “rgb” type

See variants section for the type of observation used by each environment id by default.

Variants

YarsRevenge has the following variants of the environment id which have the following differences in observation, the number of frame-skips and the repeat action probability.

Env-id

obs_type=

frameskip=

repeat_action_probability=

YarsRevenge-v0

"rgb"

(2, 5)

0.25

YarsRevenge-ram-v0

"ram"

(2, 5)

0.25

YarsRevenge-ramDeterministic-v0

"ram"

4

0.25

YarsRevenge-ramNoFrameskip-v0

"ram"

1

0.25

YarsRevengeDeterministic-v0

"rgb"

4

0.25

YarsRevengeNoFrameskip-v0

"rgb"

1

0.25

YarsRevenge-v4

"rgb"

(2, 5)

0.0

YarsRevenge-ram-v4

"ram"

(2, 5)

0.0

YarsRevenge-ramDeterministic-v4

"ram"

4

0.0

YarsRevenge-ramNoFrameskip-v4

"ram"

1

0.0

YarsRevengeDeterministic-v4

"rgb"

4

0.0

YarsRevengeNoFrameskip-v4

"rgb"

1

0.0

ALE/YarsRevenge-v5

"rgb"

4

0.25

ALE/YarsRevenge-ram-v5

"ram"

4

0.25

Difficulty and modes

It is possible to specify various flavors of the environment via the keyword arguments difficulty and mode. A flavor is a combination of a game mode and a difficulty setting. The table below lists the possible difficulty and mode values along with the default values.

Available Modes

Default Mode

Available Difficulties

Default Difficulty

[0, 32, 64, 96]

0

[0, 1]

0

Version History

A thorough discussion of the intricate differences between the versions and configurations can be found in the general article on Atari environments.

  • v5: Stickiness was added back and stochastic frame-skipping was removed. The environments are now in the “ALE” namespace.

  • v4: Stickiness of actions was removed

  • v0: Initial versions release