I want to make a new thread about this to bring attention to this issue, since now I’m quite confident it is indeed a bug in the game implementation and not my misunderstanding of the spec.
Due to easy to fix floating point precision and comparison issues, some units that have been theoretically hit to 0 actually end up being hit to 0.0000…[something], or -0.0000…[something]. The latter case is <= 0 which is fine, but the former case is not <= 0 and so any units lucky enough to get that hp value survives. This means that sometimes units are surviving when they should not.
This only happens with games with encryptors. When the decay of 0.15/frame is introduced, 0.15 cannot be represented exactly in binary, and so any float or double representation of hp’s with 0.15 added or subtracted is only an approximation.
This is not a rare. This affects maybe 25-50% of all games that I’ve analysed. Just as an example, here’s a list of games from 1520000 to 1520100 that have these “zombie” units - units with HP < 0.001:
Game 1520004: round 7
Game 1520008: round 32
Game 1520013: round 8
Game 1520018: round 5
Game 1520020: round 5
Game 1520025: round 11, 17
Game 1520050: round 29
Game 1520051: round 20, 20, 20, 20, 20
Game 1520054: round 55
Game 1520056: round 19, 27, 33, 41
Game 1520057: round 20
Game 1520061: round 27, 31
Game 1520070: round 19, 22, 30
Game 1520072: round 8, 54, 67
Game 1520074: round 10
Game 1520075: round 33
Game 1520077: round 27, 27
Game 1520087: round 9
