Starcraft AI blog

I’m still going through AIIDE 2017 games in which Steamhammer lost to weaker opponents. Steamhammer scored 98-12 against ICEbot. I thought this game on Tau Cross was full of depressing and/or informative mistakes.

The biggest mistake is that Steamhammer didn’t usually scout or react to enemy expansions. That is fixed in the development version. I think the new version would have won this game easily, despite the second mistake.

The second and interesting mistake came when ICEbot tried one of its 4 goliath drops.

Steamhammer’s notion of “this base is under attack” is not accurate. One goliath wandered outside Steamhammer’s danger recognition zone and found itself still in weapons range. It killed dozens of drones and eventually one of the hatcheries before dying. In the picture we see the totally non-dangerous goliath killing drones while Steamhammer does nothing because “the base is safe now.”

This weakness is not fixed. I’ve seen it before. The base defense code is inherited from UAlbertaBot and needs a bigger rewrite than I’ve given it.

ICEbot was playing weakly too, though, or else it would have scored more than 12 wins in 110 games. Zerg recovered from the huge deficit and made a fight of it. The game timed out after an hour with the map mined out and the winner still undecided. ICEbot was given the victory on points.

Steamhammer’s losses against ICEbot followed a curious pattern, by the way. Steamhammer lost in rounds 0, 2, 4, and 6. Then in the rest of the tournament, which ran to round 109, it lost 8 more games. Neither bot was learning, so the early losses of every second game were purely coincidence.