Difference between Breakout-v0, Breakout-v4 and BreakoutDeterministic-v4?

[tianlinxu312]

Can anyone explain the difference between Breakout-v0, Breakout-v4 and BreakoutDeterministic-v4?

[xysun]

If you look at the atari_env source code, essentially:

• v0 vs v4: v0 has repeat_action_probability of 0.25 (meaning 25% of the time the previous action will be used instead of the new action), while v4 has 0 (always follow your issued action)
• Deterministic: a fixed frameskip of 4, while for the env without Deterministic, frameskip is sampled from (2,5) (code here)

There is also NoFrameskip-v4 with no frame skip and no action repeat stochasticity.

[tianlinxu312]

If you look at the atari_env source code, essentially:

• v0 vs v4: v0 has repeat_action_probability of 0.25 (meaning 25% of the time the previous action will be used instead of the new action), while v4 has 0 (always follow your issued action)
• Deterministic: a fixed frameskip of 4, while for the env without Deterministic, frameskip is sampled from (2,5) (code here)

There is also NoFrameskip-v4 with no frame skip and no action repeat stochasticity.

Thank you very much. That's very clear.

[xysun]

Glad to help! Can you close the issue now it's solved?

[christopherhesse]

Thanks for answering @xysun!

[rfali]

Breakout-v0 vs Breakout-v4
v0: repeat_action_probability of 0.25 (meaning 25% of the time the previous action will be used instead of the new action)
v4: repeat_action_probability of 0 (always follow issued action)

Breakout-v4 vs BreakoutDeterministic-v4 vs BreakoutNoFrameskip-v4
game-vX: frameskip is sampled from (2,5), meaning either 2, 3 or 4 frames are skipped [low: inclusive, high: exclusive]
game-Deterministic-vX: a fixed frame skip of 4
game-NoFrameskip-vX: with no frame skip

Breakout-v4 vs Breakout-ram-v4
game-ram-vX: Observation Space (128,). Observation is given as a vector of size 128.
game-vX: Observation Space (210,160,3). Observation is given as pixels of Width:210, Height:160, Depth:3

The atari environment source code has been removed from Gym [AFAIK] and you can see it on the ALE's GitHub. See source code here

Other useful references:
This video
ALE v0.7 Blog which introduces the v5 versions of the game [Sep 2021].

[alexxcollins]

This thread has helped me out a lot.

@rfali - I think you may have a typo and your post should read:

Breakout-v4 vs Breakout-ram-v4
game-ram-vX: Observation Space (128,). Observation is given as a vector of size 128.
game-vX: Observation Space (210,160,3). Observation is given as pixels of Width:210, Height:160, Depth:3

[basictask]

Dear rfali,
I have checked, what you have written in game-v4 / game-ram-v4 is swapped up as alexxcollins said

[rfali]

@alexxcollins @kknydnai thanks for noticing that typo, I have updated my comment!