Starcraft AI blog

Should Steamhammer compete in the AIST competition? I’m still thinking about it. It’s not an easy decision. On the one hand, I love the idea behind the competition. It places demands on bots that I have always intended to meet eventually. On the other hand, “eventually” is a key word. The skills a bot needs to compete in AIST are not needed in any other competition, and working on them now will delay other things that I want to do.

Progress so far: I fixed the crash on Transistor. Crashes first! At the top center expansion, some mineral patches overlap the terrain in a way that fooled Steamhammer’s map analysis into believing that they are inaccessible, which indirectly caused a “should never happen” condition because of how base placement works, which caused the fatal bug, a use-after-free error. It’s good now, and Steamhammer can play games on Transistor. I fixed the endless stream of exceptions on Sparkle and Third World caused by the bot’s inability to figure out how to move a scout around the enemy base. I diagnosed Steamhammer’s inability to expand on Third World. The bot believes that the narrow ramp from the main is not passable, because the path analysis is simplified. I’m testing the fix now. It is a feature that will also be necessary on Sparkle, a partition map at walk tile resolution which says which ground areas are connected.

The topic is priorities. So:

What will improve Steamhammer the most in the short run? Tactics and micro. Steamhammer is not well-rounded. I’ve been concentrating on strategy and macro, and by now Steamhammer’s strategy and macro skills are relatively much stronger than its tactics and micro. There are weaknesses everywhere, but tactical blunders and awkward micro lose a lot more games. Throwing away overlords like they’re free, ignoring cloaked units, running an army into the enemy forces without fighting—there’s all kinds of horrible stuff.

What does my plan call for? More work on the opponent model, for multiple reasons. One, I feel the need to make at least basic progress on the machine learning part. It helps keep the goal in sight. Two, it will give Steamhammer a kind of adaptivity that bots desperately need. Three, it fits with my overall top-down development plan: Strategy first, then tactics, then micro.

What needs doing for the AIST? Mostly map skills.

• Sparkle: Basic island skills. Choose an island build order, take island bases, defend them, transfer workers, scout for enemy islands. Many regular skills need to work differently on islands.
• Sparkle: Fix the bug that prevented Steamhammer from expanding on its own starting island.
• Sparkle: Destroy the neutral building on the low-ground expansion geyser. This is the only map I know with that feature, so it’s a very specialized skill (though simple enough).
• Third World: Pathing. Understand the narrow ramp from the main. Understand the gate between the “first world” and the “third world,” which workers can mineral-walk through though it is impassible to other ground units.
• Third World: Semi-island skills. Not quite the same as island skills, though maybe I can find a way to treat them as the same.
• Transistor: Place defenses at the twin ramps, not at the natural hatchery.

I think I can probably get everything working in time, at least at a basic level. If I spend the time to do that, Steamhammer will definitely perform worse in AIIDE. Also, some of these features I was planning to delay until more infrastructure was in place, and there won’t be time to add that infrastructure for AIST. There is a risk of having to redo work later, slowing down overall progress.

So far I’m proceeding on the assumption that Steamhammer will compete. But I haven’t decided firmly.