Scarabin, on 2012-July-26, 16:38, said:
Thanks but do you not wonder where Stephen Tu gets his special information.
Why not just ask me? My information is not "special". It is just information gleaned from Matt Ginsberg's postings on rec.games.bridge and the gib-discuss email-list that used to be hosted on lists.gibware.com but is now defunct, mostly in the late 90s until 2002. Some of Matt's posts are archived on groups.google.com from the rec.games.bridge usenet group, unfortunately a lot has been lost to the sands of time of the un-archived internet. A shame that the GIB email-list archive isn't still online. Perhaps BBO has this on storage somewhere and could perhaps dig it out and make it available again? Ginsberg's posts were very educational for people who are curious about how GIB thinks and why it is prone to making the kind of mistakes it does. I probably only truly understood half of his more technical posts, but that's still more than a lot of people on the robot forum coming in and making proclamations of how it should be fixed despite knowing close to zero of how it works.
I also did some volunteer grunt work for Matt some 10-11 years ago manually combing through many hundreds of deals GIB played vs. humans on Swangames bridge, noting the more egregious bidding holes some of which Matt would attempt to fix before he quit working on GIB ~10 years ago. Unfortunately bidding is very complex with zillions of potential sequences, so there are still plenty of holes, and as new fixes are put in sometimes old things break again. As bad as GIB still is on some sequences, especially rarer ones and competitive sequences, 12 years ago it was even nuttier! Note also that Ginsberg mainly developed GIB's play engine; the bidding was based on a rules db from "Meadowlark Bridge", by Rod Ludwig. Ginsberg did modify it extensively to link it with GIB's simulations, trying to get GIB to bid more on this and use fewer rules. But he found that there were just too many holes, GIB would do its simulations & conclude that doing something crazy would work (often bidding to some high level where auctions were undefined) assuming opps couldn't deal with it (and it would be right, playing vs. itself, but real humans would just pull out the obvious penalty double etc.), so he had to turn off psyching and go back to more rules and less simulation in spots.
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Contrast his attitude with Barmar's.
Sorry, I know my posting style is blunt. But I have little tolerance for idiocy, people making declarations of how things should be done when it is clear they don't really know what they are talking about. If this comes off as arrogant, so be it. I also think it is arrogant to think that a small group of you will in your spare time in a few short years do better than Ginsberg, or people like Hans Kuijf/Yves Costel and their Jack/Wbridge programs. I agree totally with fuburules3's post above.
BTW GIB does do single-dummy reasoning after a few tricks as declarer only. If you have the commercial program, and are running the bridge.exe command prompt mode you can run with lots of different parameters described at:
http://www.gibware.com/engine.txt
Especially experiment with the -L par mode and -m # of deals parameters when working with the harder problems. When it switches to Gibson, the single-dummy engine it prints out a message "switching to Gibson" and with the -s flag you can see its method of reasoning changes.
IMO GIB does very well as declarer when given proper time controls and understands the auction (can get thrown if hits a bidding DB hole, and it biases its sample deals badly). If you think it is still making mistakes at late stages in the play, maybe post some hands where you think it is going wrong? The problems with GIB IMO are the bid DB still has tons of holes (which also affects play/defense since it uses bid info to bias its sample), defense is severely crippled from 1. inability to signal and 2. assumption of double-dummy declarer leading to solve declarer's guesses for him. The declarer play in my view is quite good. But all bets off if playing with the "basic" bots which have the Gibson turned off and the super-fast time settings, then it can play rather horrendously.
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What I want, perhaps unreasonably, is a simulation that plays and bids to the 4th level of BridgeMaster
GIBson is claimed to be 26/36 on L4 bridgemaster, although there is some debate on some of the ones GIB "missed" in the following rgb thread: (i.e. for some "missed", possible Gibson analysis defensible vs. Gitelman's)
https://groups.googl...dk/6FbE6W2QG4oJ