Monday, September 19, 2016

StarCraft AI Bots

One of the most interesting things that was mentioned in class last week was an AI competition; the AAIDE Starcraft AI Competition hosted by the University of Alberta. It sounded pretty cool to me, so I decided to check out some of the starter code that was posted for the competition. ( They give you some starter code for your bot, if you choose to use it.) There is a huge amount of what would seem to miscellaneous code to the non-StarCraft player. Things like managing workers who are building something, or making sure a proper amount of resources are being obtained for the player. Inside baseball knowledge seems to be necessary to pick out what is important and what isn’t. Perhaps the most entertaining part of the misceaallenous tasks to be encoded is that the dynamics for each race are different, even when building things.

One would assumes battle strategy has to differ greatly due to the fact each race has different types of army, but by extension everything needs to be re-coded for the three races. So it might be more accurate to say your are programming three AI’s instead of just one. While one build-order heuristic for one race might be great ( when to build what type of unit), it is completely useless for another race, because they don’t share any units or buildings.

 Another implication brought about by the management of the workers is that there is a huge amount of information that needs to be checked continuously about the game state. This is to the advantage of the computer as opposed to the human, seeing as computers excel at completing sequential trivial tasks. A little research reveals that the top Korean pro players have an APM (actions per minute) of around 300-400. I couldn’t find a breakdown as to how much of that is spent on infrastructure as opposed to actual battles. Amateurs seem to be all over the place in APM, but breaking 75 seems to be amazing. So the computer has a massive advantage here. Just based off this information about the limits of humans, it seems that computers would always be able to win.

But in fact, no. The top human players are still able to beat top AI’s consistently. In fact it seemed to be a complaint among better players that the AI that shipped with the game was laughably bad. Too predictable and easy to manipulate. These AI projects do not have the massive amounts of resources behind like Alpha Go does, but the fact remains real time strategy games are a much more complex problem.

My conclusion after reading through the starter code and documentation, is that a large amount of work goes into every bot to be programmed. Not only that — domain knowledge is crucial in this. It seems to me that there is a very small subset of people who would be able to successfully program this AI bot by themselves. It requires you to be an expert in the video game of StarCraft, as well as being well versed in AI techniques and algorithms. This seems to be a common thread when it comes to implementing most of the algorithms covered in class, deep domain knowledge is needed. 

So yes, in this case you could play video games for school work, in order to refine your domain knowledge.

For the actual meat of the AI algorithms used, check this page.

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