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title
| title |
|---|
| Skiing |
Skiing
:width: 120px
:name: Skiing
This environment is part of the Atari environments. Please read that page first for general information.
| Action Space | Discrete(3) |
| Observation Shape | (210, 160, 3) |
| Observation High | 255 |
| Observation Low | 0 |
| Import | gymnasium.make("ALE/Skiing-v5") |
For more Skiing variants with different observation and action spaces, see the variants section.
Description
You control a skier who can move sideways.The goal is to run through all gates (between the poles) in the fastest time.You are penalized five seconds for each gate you miss.If you hit a gate or a tree, your skier will jump back up and keep going.
For a more detailed documentation, see the AtariAge page
Actions
Skiing has the action space Discrete(3) with the table below lists the meaning of each action's meanings.
As Skiing uses a reduced set of actions for v0, v4 and v5 versions of the environment.
To enable all 18 possible actions that can be performed on an Atari 2600, specify full_action_space=True during
initialization or by passing full_action_space=True to gymnasium.make.
| Value | Meaning | Value | Meaning | Value | Meaning |
|---|---|---|---|---|---|
0 |
NOOP |
1 |
RIGHT |
2 |
LEFT |
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
Seconds are your only rewards - negative rewards and penalties (e.g. missing a gate) are assigned as additional seconds.
For a more detailed documentation, see the AtariAge page [SLALOM RACING section].
Variants
Skiing 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= |
|---|---|---|---|
| Skiing-v0 | "rgb" |
(2, 5) |
0.25 |
| Skiing-ram-v0 | "ram" |
(2, 5) |
0.25 |
| Skiing-ramDeterministic-v0 | "ram" |
4 |
0.25 |
| Skiing-ramNoFrameskip-v0 | "ram" |
1 |
0.25 |
| SkiingDeterministic-v0 | "rgb" |
4 |
0.25 |
| SkiingNoFrameskip-v0 | "rgb" |
1 |
0.25 |
| Skiing-v4 | "rgb" |
(2, 5) |
0.0 |
| Skiing-ram-v4 | "ram" |
(2, 5) |
0.0 |
| Skiing-ramDeterministic-v4 | "ram" |
4 |
0.0 |
| Skiing-ramNoFrameskip-v4 | "ram" |
1 |
0.0 |
| SkiingDeterministic-v4 | "rgb" |
4 |
0.0 |
| SkiingNoFrameskip-v4 | "rgb" |
1 |
0.0 |
| ALE/Skiing-v5 | "rgb" |
4 |
0.25 |
| ALE/Skiing-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