Starcraft AI blog

1. The feature of retreating to the natural base if it exists is buggy. Steamhammer always retreats to the natural, whether it has been taken or not, causing trouble especially in ZvZ games. This is hilarious, if “hilarious” means “it’s bad, but at least it’s easy to fix.” I added the feature at the last minute with only a brief test: Tally another loss for poor testing and inadequate commenting!

2. Meanwhile, units that retreat to recover from their damage still return to the main, not the natural. In general, the code has confusions between retreating the squad and retreating individual units to regenerate (which only applies to melee units, and only if configured). It doesn’t seem urgent to fix, though.

3. A unit which is inside the minimum range of a sieged tank refuses to retreat with its squad. It doesn't necessarily attack the tank, but it attacks something. This behavior has only triggered a couple times, but so far it looks like a successful improvement.

4. The system of pulling workers for defense is questionable. If it made correct decisions, it would be great. As it stands, it is sometimes good and sometimes bad, and I can’t judge whether it is worth it overall. It averages out pretty close to zero, maybe?

5. I thought the loss against Stone was due to a new weakness, but on a closer look I don’t see one. It’s the first loss against Stone since worker harass defense was implemented, so I’ll test more closely to make sure.

6. Speaking of worker harass, gas workers now defend themselves the same way as mineral workers. I don’t know whether this will turn out to be a win, because harassed gas workers get switched out; harassment can potentially disrupt gas mining. So far, this behavior has triggered against LetaBot, when it looked highly effective. But LetaBot is a lazy harasser, so the jury is still out.

7. Other surprise losses by Steamhammer were due to randomly choosing openings that the opponent countered. For example, in the first ever loss against protoss Lukas Moravec, Steamhammer went 5 pool, which was objectively poor against the 2 gate opening. Steamhammer nevertheless pulled ahead and was winning until it bungled its tech switch.

I’ll be inserting another bug-fix release to solve the retreat-to-natural bug before I get down to features.