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optimizing one opening build

Yesterday I revised the ZvP_10Hatch opening. It was originally designed to counter 2 gate zealot rushes, and now (with the opponent model) it is used to counter expected heavy rushes by terran and random opponents too. I renamed it Over10Hatch. The basic build order is extractor trick for a 10th drone, overlord, hatchery, and a couple of sunkens to help hold off the mass zealot pressure so it’s safe to make drones and tech.

The changes are small. If you watch casually, you might not notice. The extractor trick is now before the overlord, not after, a careless oversight in the original. The first sunken is delayed slightly, and the second sunken needed to deter masses of zealots is delayed longer. The number of early zerglings is cut back to just the number needed in the worst case. The early game plays out much as before, it only looks as though Steamhammer might be cutting it a little close. (CherryPi’s versus-protoss opening often gives a similar impression. The team knows what it is doing.) You could miss that there is a slightly higher drone count.

A pro would cut it closer, but a pro has good judgment. The way the rest of the game plays out looks different. In the old build, Steamhammer would often narrowly hold the zealots, get lurkers just in time to survive, and use the opponent’s lack of tech to slowly push for victory. With the extra income from the new build, Steamhammer holds the zealot pressure easily, safely gets lurkers, and quickly smashes the protoss with a mass of lurkers and lings. The turnaround in the game looks completely different. The effect versus no-academy marine rushes like UAlbertaBot’s is similar.

I thought it was a good lesson in the importance of an efficient build.

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Edmund Nelson on :

Given the difference in mining between bot and human play (using the mineral pathing algorithm described in 2013 if there is an updated version I would love to see it) bots mine 15% more minerals off of 1 base with 18 workers compared to a 1 base human. But 0% more minerals with 2 bases and 18 workers compared to a 2 base human. Doesn't this mean that building additional bases as an ai is much less profitable than it would be in human v human play? According to my estimates it takes humans 1.7 minutes (1 minute 40 seconds on Fastest speed) of mining off of a second base before they profit from the additional minerals gathered. A bot meanwhile takes 4 minutes 10 seconds before they get profit from a new expo vs another bot? (note this ignores the other benefit of expansions which is the ability to build workers 2x as fast)

Can you confirm if this paper napkin math is correct? If so this indicates that bot BO's need to be completely divergent from human BO's, given that you get both A: more minerals per worker than a human and B: less benefit from expanding than a human.

I admit I'm an economist and not a computer programmer sooner or later i'll hunker down and learn enough programming to actually make my first sc1 bot, but that day is long away.

Jay Scott on :

Without checking the math: On the one hand, 1. Skilled humans (even well below pro level) do some mining speedup tricks too, with good building placement and with micro in the early game when they can spare the time, so the difference may be less than you are thinking. 2. The gas income is also important. On the other hand, 3. Bot skills and human skills differ in many other ways. How you should open depends on your skill in following up. My thinking is that the detailed build orders and the mix of openings that a bot plays should probably be somewhat different than human—but not entirely different, it will still look familiar.

Jay Scott on :

I’d also say, don’t discount human knowledge too much. I’m reminded of an interview with computer chess programmers. One of them mentioned the opening that a top program plays when told to play without an opening book, figuring out each move for itself on the fly. These programs are far stronger than any human, so what opening does it play? Najdorf Sicilian, also the favorite for decades of many top grandmasters.

krasi0 on :

I am feeling curious. Could you elaborate more on that story? How has the particular computer chess program converged on that opening (NS)? Has it been hardcoded?

Jay Scott on :

http://www.chessdom.com/interview-with-robert-houdart-mark-lefler-and-gm-larry-kaufman/

Jay Scott on :

The implication in the interview is that chess programs have become so strong that they can discover during a game, by their own search and evaluation, strong opening lines that grandmasters spent decades honing.

MicroDK on :

Strictly, that build should be called 10OverHatch... ;)

MicroDK on :

Anyway, can it hold a 2 gate zealot rush on all SSCAIT maps reliably? In my tests, the natural hatch in 10Hatch is sometimes too late, and the zealots reach the natural hatch before it is hatched and sunkens can get be made. That is why Microwave is using 9Hatch vs bots like Wuli and Lucas Moravec (who did 2 gate zealot rushes 100% of the times in its early days).

Jay Scott on :

Really! I found the hatchery to be in time on every map against 9-9 gate or later, and (as I mentioned) even delay the sunken slightly. I played dozens of games against 3 different zealot rushers and got one loss, which was for different reasons.

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