Starcraft AI blog

I’m working on version 1.4 now, and the major feature in version 1.4 will be opponent modeling. But after the AIIDE rush I felt tired of opponent modeling, and discouraged by the bugs, so I’m improving scouting first. Good scouting is important for opponent modeling to work well, so I’m happy to do scouting in the same version. No more rush; I will take my time and do it right.

I added a Recon squad that scouts around with ground units in the middle game, as soon as there are enough ground units to spare a few for scouting. It doesn’t search efficiently, but it does catch enemy expansions sooner or later, and sends eyes around the map to places Steamhammer used to ignore. I also made a small tactical change so that the attack squads are less maniacally focused on the enemy main base and more willing to attack other bases. Besides improving opponent modeling, I think it should help directly against most opponents that try to mass expand or to hide expansions.

I also refactored code so that I can work on overlord scouting. The first overlord will coordinate its movement with the scouting drone. Currently, if Steamhammer sends out both its first overlord and a scouting drone, they both head for the same base. It’s disgusting, but it has been that way since December when I first hacked in crude overlord scouting. Overlord scouting in 1.4 won’t be a polished gem, but it shouldn’t be a dirt clod any more.

I’m also making the usual random improvements here and there to things I come across. I finally realized why Steamhammer keeps making guardians against XIMP by Tomas Vajda: It doesn’t recognize that corsairs and carriers counter guardians. Oops. I left out that bit of knowledge and only now caught the mistake.

biggest weaknesses

The worst news is Steamhammer is doing poorly against the top protoss bots lately, for two reasons. First, some are using multiple strategies, and the current Steamhammer’s random openings cannot counter all of them. Opponent modeling should help. Second, protoss is often playing forge expand or other big macro openings, which Steamhammer only partially understands. Opponent modeling will again help, because then Steamhammer should usually be able to find good strategies in response, instead of only occasionally. But opponent modeling won’t be enough (unless it sticks with timing attacks like hydra bust), because Steamhammer’s tactics tend to break down in a big macro game. To have the right units at the right time is no help if you throw them away. Fixing tactical play, the way I intend to do it, will be another major feature.

In other words, I expect to have to finish 2 more major features, opponent modeling and tactical analysis, before Steamhammer can score consistently against top protoss bots. It won’t happen soon. Opponent modeling is underway, but tactical analysis likely won’t be until next year.

I will be able to make progress on small features. The 3 biggest weaknesses that can be corrected with minor features are:

1. Better worker micro. Drills would help in a lot of defensive situations. Even without drills, better choices about engaging and running away would reduce losses.

2. Run workers away from enemy attacks. It’s a basic skill that top bots have to some degree and Steamhammer doesn’t. Steamhammer not only loses workers in a base under enemy attack, it transfers more to the base to try to keep mining gas. Keeping workers alive would be a big boost to resilience. I will likely stop the transfers as one fix, and run workers away as a later fix.

3. Pathing in the presence of map blocks. Units too often get stuck trying to take a path that is blocked. The work to fix pathing is started, and I see it as related to dropping BWTA. I’ll continue step by step.

I’m not working on any of these 3 at the moment. One goal at a time. In 1.4 I will probably take at least one more step toward removing BWTA.