Starcraft AI blog

I promised a post about how Steamhammer can eventually optimize its own openings. In fact, I intend for it to be able to invent its own openings from scratch, as well as adjust openings (whether hand written or automatically generated) based on calculations and experience. Here’s an outline of my ideas.

My next big project is strategy adaptation. A large part of it will be implementing abstract strategies and the ability to turn them into concrete lines of play. For example, “3 hatch muta” is an abstract strategy at a high level of abstraction, and Steamhammer’s opening lines ZvT_3HatchMuta and ZvP_3HatchMuta are concrete implementations of the strategy, optimized for different matchups. Once abstract strategies exist, Steamhammer will be able to experiment with different strategies by simply filling in its abstract strategy data structure—with random values if no other way—and playing out the game, turning the abstract strategy into a build order. I suppose I’ll do this at home rather than during tournaments! There are more focused ways to find new abstract strategies: Steal them from opponents, extract them from replays, systematically explore the lattice of strategies (since they are partially ordered) extending the promising avenues, note enemy timings and units and do a directed search for strategies that hit the timings and counter the units. The space of abstract strategies is exponentially easier to search than the space of build orders; that is the advantage of abstraction.

Another part of the strategy adaptation project is to collect data on opening lines—aka concrete build orders—with their resource use and timings and unit counts and stuff. If we play out a strategy and get a build order, we record the build order as an opening, and if we play the opening we measure its data in real games. With the measured data, we can compare openings to judge which one is better in a given situation: Does it hit the timings, does it counter the units, does it grow a strong enough economy, does it have adequate defenses?

One way to do the comparison, which both I and others have suggested, is to set up the armies of both sides and run the combat simulator. That compares army strengths; if you also know economy size and tech level, you can do a more comprehensive comparison.

Once you can compare 2 opening lines for goodness in a given scenario, you can optimize an opening line for the scenario without changing its abstract strategy. I think I’ll try goal-directed modifications to the opening line—the enemy attacked early here, we need units in time; or the enemy had too much stuff later, we need more drones to keep up. Modifications that pass the comparison check can be tried in games.

Many new skills are needed. My plans are more than my accomplishments, and my accomplishments turn out different from their original plans. Even so, I expect to get a system like this working eventually. If you try a new idea on Steamhammer and it has no counter, it will invent its own counter and polish it by experience and reasoning. Then I’ll have gotten somewhere.