--- title: MsPacman --- # MsPacman ```{figure} ../../_static/videos/atari/ms_pacman.gif :width: 120px :name: MsPacman ``` This environment is part of the Atari environments. Please read that page first for general information. | | | |---|---| | Action Space | Discrete(9) | | Observation Space | Box(0, 255, (210, 160, 3), uint8) | | Import | `gymnasium.make("ALE/MsPacman-v5")` | For more MsPacman variants with different observation and action spaces, see the variants section. ## Description Your goal is to collect all of the pellets on the screen while avoiding the ghosts. For a more detailed documentation, see [the AtariAge page](https://atariage.com/manual_page.php?SoftwareLabelID=924) ## Actions MsPacman has the action space of `Discrete(9)` with the table below listing the meaning of each action's meanings. 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` | `UP` | `2` | `RIGHT` | | `3` | `LEFT` | `4` | `DOWN` | `5` | `UPRIGHT` | | `6` | `UPLEFT` | `7` | `DOWNRIGHT` | `8` | `DOWNLEFT` | ## 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 MsPacman 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= | |------------------------------|-------------|--------------|------------------------------| | MsPacman-v0 | `"rgb"` | `(2, 5)` | `0.25` | | MsPacman-ram-v0 | `"ram"` | `(2, 5)` | `0.25` | | MsPacman-ramDeterministic-v0 | `"ram"` | `4` | `0.25` | | MsPacman-ramNoFrameskip-v0 | `"ram"` | `1` | `0.25` | | MsPacmanDeterministic-v0 | `"rgb"` | `4` | `0.25` | | MsPacmanNoFrameskip-v0 | `"rgb"` | `1` | `0.25` | | MsPacman-v4 | `"rgb"` | `(2, 5)` | `0.0` | | MsPacman-ram-v4 | `"ram"` | `(2, 5)` | `0.0` | | MsPacman-ramDeterministic-v4 | `"ram"` | `4` | `0.0` | | MsPacman-ramNoFrameskip-v4 | `"ram"` | `1` | `0.0` | | MsPacmanDeterministic-v4 | `"rgb"` | `4` | `0.0` | | MsPacmanNoFrameskip-v4 | `"rgb"` | `1` | `0.0` | | ALE/MsPacman-v5 | `"rgb"` | `4` | `0.25` | | ALE/MsPacman-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, 1, 2, 3]` | `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