Starcraft AI blog

Dragon’s learning file format is spare, one line for each game giving strategy name and win or loss, nothing more. Dragon has 7 strategies, and against most opponents tried all of them. Its habit is to keep with a winning strategy, trying others sporadically but generally switching when the current plan starts to fail.

Dragon calls its worker rush “dirty worker rush”. Perhaps we should get it together with Stone so it can learn a nice clean worker rush.

As you can see in the “first” column (the first game each strategy was played), Dragon tried all 7 strategies in the first 7 games because they all lost on their first tries. Worker rush turned out to be the most successful plan, as far as that goes, which is very interesting. Mass vultures were the most-played plan despite not having the highest win rate, apparently because the worker rush had a string of losses so that vultures looked better in recent games. (Maybe Dragon figured that Stardust had learned how to deal with the worker rush.)

How did mass vultures have any chance against Stardust’s dragoons? I located a couple of the “mass vulture” wins and watched them. In fact, tanks were the core of Dragon’s army and the vultures acted as buffer. It looked like regular tank-vulture unit mix with regular tank pushes.

Against PurpleWave, and BananaBrain below, most Dragon strategies worked about equally well. Apparently it has well-balanced play against protoss. Actually I think the explanation may be different: Once the opening is over, Dragon quickly adapts to the enemy, playing against the units it sees. If I guess right, then its goal in the opening is to survive in a good position, and after that Dragon will produce whatever units it needs, so the opening doesn’t much affect the outcome. Obviously the worker rush doesn’t leave much room for adaptation, so it is an exception.

This hypothesis explains why Dragon can do well though it records so little data about each game: The openings often don’t much matter.

Fast expand works versus McRave...

2 barracks is good against Microwave...

... but against Steamhammer, again, most strategies look about the same. Watching games, I think Dragon converges on a diverse unit mix fairly quickly after the opening.

I checked out a “mass vulture” game against Steamhammer, and it looked different from the same strategy against Stardust. Dragon made a modest number of vultures and researched spider mines, but added tanks and wraiths and soon the unit mix looked like most Dragon-Steamhammer games.

Most curious: Against ZZZKBot, factory openings predominate. Checking the game durations, most games that ZZZKBot won were short, meaning that it played its 4 pool with success. Most games that Dragon won were longer, so either ZZZKBot did not 4 pool or else Dragon was slow to counterattack after surviving.