
Ask HN: What can AlphaStar tell us about imitation learning for autonomous cars? - strangecosmos
I find it intriguing that DeepMind’s AlphaStar used supervised imitation learning on a dataset of 500,000+ human-played games. With supervised imitation learning alone, it was able to beat the StarCraft Elite AI bot 95% of the time, and get an estimated MMR that would put it in the Gold league — where the middle third of ranked human players are. So just with imitation learning, AlphaStar was able to get to roughly median human performance (or at least we think so; I don’t know if it beat any Gold-ranked human players).<p>The Information reported (https:&#x2F;&#x2F;www.theinformation.com&#x2F;articles&#x2F;what-makes-teslas-autopilot-different) that Tesla is using supervised imitation learning to “directly predict the correct steering, braking and acceleration” based on the state&#x2F;action pairs observed in human driving. Should we feel optimistic that what (apparently) worked for StarCraft will work for autonomous cars?
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luckylion
The big point of AlphaStar wasn't the "learning" part (that is: strategies,
build order), it was the micro part (control of individual units).

Even with the same APM (action per minute) as a human, it has a huge
advantage. It can control units in different areas in the same time, and do so
perfectly. It doesn't have tiny imperfections. That adds up quickly in star
craft 2, and gives it a great advantage.

Does that translate into real world applications? Computers are already much
better at reaction time and, once they calculated everything and a decision
has been reached, executing it perfectly. That'll probably help in piloting as
well - thinking of it as a human that steps on the brake a little bit earlier,
doesn't oversteer etc. Tiny advantages can make the difference between a crash
and a close call. It's not the great breakthrough though.

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strangecosmos
I just watched the live-streamed match where MaNa beat AlphaStar and the
professional commentators seemed to think that AlphaStar had good strategy.
MaNa had even copied something AlphaStar did in a previous match.

[https://youtu.be/cUTMhmVh1qs](https://youtu.be/cUTMhmVh1qs)

I have not played much StarCraft, so I can’t judge for myself.

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luckylion
Sure, it does some stuff that's fine, but that's not what makes it win (yet).
It's basically playing in Archon mode (but alone) where it can see and act all
over the map at the same time - humans can't do that. I'm sure it will at some
point become better at strategies, too, but so far it's hard to compare
because the API it has is much more powerful.

When they did change that aspect of the match, the 10:0 turned into 10:1.
Would Mana have won the next 10 games? Nobody knows, but at least it would've
been a lot closer. SC2 rewards micro a lot, and a computer will always be
better at micro than a human (unless you make it harder for the machine).
[https://www.youtube.com/watch?v=3PLplRDSgpo](https://www.youtube.com/watch?v=3PLplRDSgpo)
This is a couple of years old, and at that level, it would certainly beat any
pro, even without a superior strategy because micro is a leverage for unit
strength.

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cjbprime
Gold's currently 30th-50th percentile, so more like "slightly below average"
than "middle third":
[https://www.rankedftw.com/stats/leagues/1v1/#v=2&r=-2&sx=a](https://www.rankedftw.com/stats/leagues/1v1/#v=2&r=-2&sx=a)

The problem with autonomous cars will be the "error bars" \-- playing at a
diamond level but occasionally losing a game due to a bronze level mistake is
impressive for a Starcraft bot and deadly for an autonomous driving bot.

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strangecosmos
Oh. Is the info on this wiki outdated?
[https://starcraft.fandom.com/wiki/League_(StarCraft_II)#Leag...](https://starcraft.fandom.com/wiki/League_\(StarCraft_II\)#League_Types)

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cjbprime
Very. The page says "As of Heart of the Swarm". This was released in 2013, and
obsoleted by Legacy of the Void in 2015.

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strangecosmos
Gotcha! Thanks. I have only played a bit of StarCraft II so I’m not super
familiar.

