|
1 | | ---- |
2 | | -title: Alien |
3 | | ---- |
4 | | - |
5 | | -# Alien |
6 | | - |
7 | | -```{figure} ../../_static/videos/atari/alien.gif |
8 | | -:width: 120px |
9 | | -:name: Alien |
10 | | -``` |
11 | | - |
12 | | -This environment is part of the <a href='..'>Atari environments</a>. Please read that page first for general information. |
13 | | - |
14 | | -| | | |
15 | | -|---|---| |
16 | | -| Action Space | Discrete(18) | |
17 | | -| Observation Space | Box(0, 255, (210, 160, 3), uint8) | |
18 | | -| Import | `gymnasium.make("ALE/Alien-v5")` | |
19 | | - |
20 | | -For more Alien variants with different observation and action spaces, see the variants section. |
21 | | - |
22 | | -## Description |
23 | | - |
24 | | -You are stuck in a maze-like space ship with three aliens. You goal is to destroy their eggs that are scattered all over the ship while simultaneously avoiding the aliens (they are trying to kill you). You have a flamethrower that can help you turn them away in tricky situations. Moreover, you can occasionally collect a power-up (pulsar) that gives you the temporary ability to kill aliens. |
25 | | - |
26 | | -For a more detailed documentation, see [the AtariAge page](https://atariage.com/manual_html_page.php?SoftwareID=815) |
27 | | - |
28 | | -## Actions |
29 | | - |
30 | | -Alien has the action space `Discrete(18)` with the table below listing the meaning of each action's meanings. |
31 | | -As Alien 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`. |
32 | | - |
33 | | -| Value | Meaning | Value | Meaning | Value | Meaning | |
34 | | -|---------|--------------|---------|-----------------|---------|----------------| |
35 | | -| `0` | `NOOP` | `1` | `FIRE` | `2` | `UP` | |
36 | | -| `3` | `RIGHT` | `4` | `LEFT` | `5` | `DOWN` | |
37 | | -| `6` | `UPRIGHT` | `7` | `UPLEFT` | `8` | `DOWNRIGHT` | |
38 | | -| `9` | `DOWNLEFT` | `10` | `UPFIRE` | `11` | `RIGHTFIRE` | |
39 | | -| `12` | `LEFTFIRE` | `13` | `DOWNFIRE` | `14` | `UPRIGHTFIRE` | |
40 | | -| `15` | `UPLEFTFIRE` | `16` | `DOWNRIGHTFIRE` | `17` | `DOWNLEFTFIRE` | |
41 | | - |
42 | | -## Observations |
43 | | - |
44 | | -Atari environments have three possible observation types: `"rgb"`, `"grayscale"` and `"ram"`. |
45 | | - |
46 | | -- `obs_type="rgb" -> observation_space=Box(0, 255, (210, 160, 3), np.uint8)` |
47 | | -- `obs_type="ram" -> observation_space=Box(0, 255, (128,), np.uint8)` |
48 | | -- `obs_type="grayscale" -> Box(0, 255, (210, 160), np.uint8)`, a grayscale version of the "rgb" type |
49 | | - |
50 | | -See variants section for the type of observation used by each environment id by default. |
51 | | - |
52 | | -## Rewards |
53 | | -You score points by destroying eggs, killing aliens, using pulsars, and collecting special prizes. When you are caught by an alien, you will lose one of your lives. The number of lives you have depends on the game flavor. For a table of scores corresponding to the different achievements, consult the [AtariAge page](https://atariage.com/manual_html_page.php?SoftwareID=815). |
54 | | - |
55 | | -## Variants |
56 | | - |
57 | | -Alien has the following variants of the environment id which have the following differences in observation, |
58 | | -the number of frame-skips and the repeat action probability. |
59 | | - |
60 | | -| Env-id | obs_type= | frameskip= | repeat_action_probability= | |
61 | | -|---------------------------|-------------|--------------|------------------------------| |
62 | | -| Alien-v0 | `"rgb"` | `(2, 5)` | `0.25` | |
63 | | -| Alien-ram-v0 | `"ram"` | `(2, 5)` | `0.25` | |
64 | | -| Alien-ramDeterministic-v0 | `"ram"` | `4` | `0.25` | |
65 | | -| Alien-ramNoFrameskip-v0 | `"ram"` | `1` | `0.25` | |
66 | | -| AlienDeterministic-v0 | `"rgb"` | `4` | `0.25` | |
67 | | -| AlienNoFrameskip-v0 | `"rgb"` | `1` | `0.25` | |
68 | | -| Alien-v4 | `"rgb"` | `(2, 5)` | `0.0` | |
69 | | -| Alien-ram-v4 | `"ram"` | `(2, 5)` | `0.0` | |
70 | | -| Alien-ramDeterministic-v4 | `"ram"` | `4` | `0.0` | |
71 | | -| Alien-ramNoFrameskip-v4 | `"ram"` | `1` | `0.0` | |
72 | | -| AlienDeterministic-v4 | `"rgb"` | `4` | `0.0` | |
73 | | -| AlienNoFrameskip-v4 | `"rgb"` | `1` | `0.0` | |
74 | | -| ALE/Alien-v5 | `"rgb"` | `4` | `0.25` | |
75 | | -| ALE/Alien-ram-v5 | `"ram"` | `4` | `0.25` | |
76 | | - |
77 | | -## Difficulty and modes |
78 | | - |
79 | | -It is possible to specify various flavors of the environment via the keyword arguments `difficulty` and `mode`. |
80 | | -A flavor is a combination of a game mode and a difficulty setting. The table below lists the possible difficulty and mode values |
81 | | -along with the default values. |
82 | | - |
83 | | -| Available Modes | Default Mode | Available Difficulties | Default Difficulty | |
84 | | -|-------------------|----------------|--------------------------|----------------------| |
85 | | -| `[0, 1, 2, 3]` | `0` | `[0, 1, 2, 3]` | `0` | |
86 | | - |
87 | | -## Version History |
88 | | - |
89 | | -A thorough discussion of the intricate differences between the versions and configurations can be found in the general article on Atari environments. |
90 | | - |
91 | | -* v5: Stickiness was added back and stochastic frame-skipping was removed. The environments are now in the "ALE" namespace. |
92 | | -* v4: Stickiness of actions was removed |
93 | | -* v0: Initial versions release |
| 1 | +<html> |
| 2 | + <head> |
| 3 | + <meta http-equiv="refresh" content="0; url=https://ale.farama.org/environments/alien"> |
| 4 | + <title>Redirecting to Atari Documentation's new home</title> |
| 5 | + </head> |
| 6 | + <body> |
| 7 | + <p>If you are not redirected automatically, follow this <a href="https://ale.farama.org/environments/alien">link to the new page</a>.</p> |
| 8 | + </body> |
| 9 | +</html> |
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