Krull#

../../../_images/krull.gif

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

Action Space

Discrete(18)

Observation Shape

(210, 160, 3)

Observation High

255

Observation Low

0

Import

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

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

Description#

Your mission is to find and enter the Beast’s Black Fortress, rescue Princess Lyssa, and destroy the Beast.The task is not an easy one, for the location of the Black Fortress changes with each sunrise on Krull.

For a more detailed documentation, see the AtariAge page

Actions#

Krull has the action space Discrete(18) with the table below lists the meaning of each action’s meanings. As Krull 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

Observations#

Atari environment have two possible observation types, the observation space is listed below. See variants section for the type of observation used by each environment id.

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

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

Additionally, obs_type="grayscale" cause the environment return a grayscale version of the rgb array for observations with the observation space being Box(0, 255, (210, 160), np.uint8)

Rewards#

You will receive various scores for each monster you kill. You can play the game until you have lost all your lives. For a more detailed documentation, consult the AtariAge page.

Variants#

Krull 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=

Krull-v0

"rgb"

(2, 5)

0.25

Krull-ram-v0

"ram"

(2, 5)

0.25

Krull-ramDeterministic-v0

"ram"

4

0.25

Krull-ramNoFrameskip-v0

"ram"

1

0.25

KrullDeterministic-v0

"rgb"

4

0.25

KrullNoFrameskip-v0

"rgb"

1

0.25

Krull-v4

"rgb"

(2, 5)

0.0

Krull-ram-v4

"ram"

(2, 5)

0.0

Krull-ramDeterministic-v4

"ram"

4

0.0

Krull-ramNoFrameskip-v4

"ram"

1

0.0

KrullDeterministic-v4

"rgb"

4

0.0

KrullNoFrameskip-v4

"rgb"

1

0.0

ALE/Krull-v5

"rgb"

4

0.25

ALE/Krull-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]

0

[0]

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 frameskipping was removed. The environments are now in the “ALE” namespace.

  • v4: Stickiness of actions was removed

  • v0: Initial versions release