Starcraft AI blog

For this upload of Steamhammer to SSCAIT, I turned on display of the strategy boss information. It’s kind of cryptic, so I thought I’d explain.

The top section, with all yellow labels from “bases” to “build”, describes the game situation and some automatic reactions that can happen at any time, including during the opening. The top section displays all game long. Then comes a slight break, and the bottom section, with multi-color labels from “eco” to the end, describes the strategy boss’s plans and conclusions after the opening is over. The bottom section only appears after exit from the opening book.

The strategy boss also cares about the game’s mineral count, gas count, and supply count. That’s why I draw the strategy boss info directly underneath Starcraft’s info.

bases 3/12 Steamhammer owns 3 of the 12 bases on the map.

patches 20 These 3 bases have 20 mineral patches total. This determines the upper limit of how fast it is possible to mine minerals.

geysers 2+0 Steamhammer has taken 2 gas geysers, and no more are available. If a geyser is in the process of being taken—the extractor is morphing—then it doesn’t count on either side. With 3 bases and 2 geysers, it could be that Steamhammer has 2 gas bases and a mineral only, or 3 gas bases and the final geyser is in the process of being taken.

drones 27/39 Steamhammer has 27 drones, including drones that are in the egg and haven’t hatched yet. It will spawn up to 39 drones; it believes that, taking into account the mineral patches and geysers, 39 drones are as many as it is reasonable to make.

mins 23 23 of the drones are mining minerals.

gas 0 None of the drones are mining gas. That leaves 4 drones on neither minerals or gas; they may be still in the egg, or may be carrying out other business, like building or scouting. But in any case, gas collection is turned off at the moment so that Steamhammer can collect minerals faster.

react +16 Based on what we’ve seen the opponent do, aim for 16 drones more than what we would normally build in this situation; they are “reactive drones.” A number as large as +16 usually means that the opponent is playing very defensively with many cannons, so that we can safely make extra drones to get ahead in economy.

larvas 0 There are no larvas available to spawn more units. Steamhammer takes a shortage of larvas as evidence that it may need more hatcheries (other factors count too). That might be why gas is turned off: To collect minerals faster to make a macro hatchery ASAP. (Though it might have concluded only that 911 gas is more than it needs for now.)

build +0g +0h This describes a complex strategy reaction that can occur in the opening book, and cannot occur later in the game. It connects with the “react” item above, the count of reactive drones. If there are too many reactive drones in the opening, they will bring in excess minerals, so Steamhammer takes actions to use resources more efficiently and prevent the excess minerals from building up unused. The actions are that it can take extra geysers—“g”—or make extra hatcheries—“h”. The extra geysers bring in extra gas so that income is balanced, and the extra hatcheries bring extra larvas for faster production. The result is that the unplanned resources can be spent efficiently and Steamhammer runs through its opening line faster, entering the middle game in a stronger position. In this game, it did not add anything extra in the opening; most of the +16 reactive drones must have been decided after the book line was over.

eco 0.35 5/43 describes plans for economic growth. 0.35 is the proportion of larvas planned to be made into drones on average over the long run. Actual moment-to-moment drone production can vary from all drones to all combat units, depending on circumstances, but Steamhammer aims for a given ratio. 5/43 is the actual ratio of drone production: It made 5 drones out of the last 43 larvas morphed, a ratio of about 0.11—Steamhammer is behind on planned drone production. Reactive drones are implemented behind the scenes by manipulating the ratio.

army 24 40 bad gives army sizes: Steamhammer’s army size is 24 (in an arbitrary measure), including static defense, and the enemy’s army size is 40, counting only mobile units. This is “bad” in red because it means that Steamhammer may be overrun. When the army size is “bad” Steamhammer makes combat units to defend itself; that explains why it is behind on drone production.

The 7 orange unit types lings, hydras, lurkers, mutas, guardians, devourers, ultras, are the candidate units for Steamhammer’s main unit mix. Overlords, queens, and defilers are support units that are made on the side and do not count toward the main unit mix. The number after each unit type is the strategy boss’s score for how important the unit type is in the current situation. The scores are used for two purposes: First, to decide on the combat unit mix. Second, to decide on the tech target, the next unit type that the bot should aim for.

The starred unit types are those that Steamhammer has the tech for. They are candidates for the unit mix. The starred unit with the highest score will be part of the unit mix. The rest of the unit types are candidates for the tech target.

Zergling Hydralisk 1 Lurker is the combat unit mix. Hydras had the highest score, so they are part of the unit mix. The full rules for choosing the unit mix are complex. Lurkers had the next highest score, but the strategy boss decided that it is enough to have only 1 lurker for now (which really means at least 1 lurker; if there happen to already be more, that is OK). Minerals not spent on hydras or the 1 lurker (or on drones or whatever else) will be spent on zerglings.

plan Mutas gives the tech target: A tech switch to mutalisks is planned. Mutas are a candidate for the tech target because they have a higher score than any of the starred units that Steamhammer already has the tech for. Guardians and ultras have higher scores yet, but Steamhammer doesn’t have a hive so mutalisks can be gotten much faster. If mutas did not score higher than hydras, the strategy boss would have picked guardians as the tech target.