Author: Robert Hyatt
Date: 18:44:07 12/23/03
Go up one level in this thread
On December 23, 2003 at 18:25:26, Christophe Theron wrote: >On December 23, 2003 at 09:49:27, Anthony Cozzie wrote: > >>On December 23, 2003 at 08:50:51, Amir Ban wrote: >> >>>On December 23, 2003 at 08:09:34, Uri Blass wrote: >>> >>>>On December 23, 2003 at 06:47:18, Amir Ban wrote: >>>> >>>>> >>>>>Thanks for running this match and for the interesting commentary. >>>>> >>>>>My point in playing this match was never to show how weak crafty is, but >>>>>something different: Too many programmers and posters in this forum take the >>>>>speed issue way too seriously. They don't understand the importance of >>>>>evaluation, and when they do think about it, they think it's about pawn >>>>>structure and a few super-rare endgame tableaus. >>>>> >>>>>I also needed to check that I've not been wasting my efforts in the last few >>>>>years. >>>>> >>>>>Merry Christmas and Happy Hanukka, >>>>>Amir >>>> >>>>I do not claim that evaluation is not important but my opinion is that search is >>>>not thing that is less important. >>>> >>>>I also know that inspite of the fact that you say that evaluation is important >>>>your evaluation takes only 20% of Junior's time(I do not know about latest >>>>Junior but I know about previous post of you). >>>> >>> >>>Less than 10% in most positions. >>> >>> >>>>How is it possible? >>>> >>>>Did not you find important things to evaluate that it is simply impossible to >>>>evaluate them fast? >>>> >>> >>>There are many things I can do basically for free in my framework. There are >>>things that break the model, and either are neglected or if considered critical >>>get done outside it. >>> >>> >>>>For example let talk about pieces that are in danger of being trapped because >>>>the opponent control every square that they can goto. >>>> >>>>There are cases that you need to search many plies forward to see by search that >>>>they are really trapped but a good evaluation should detect the danger. >>>> >>>>Correct me if I am wrong but I guess that you do not evaluate this information >>>>in every node that you evaluate otherwise you cannot be faster in nps than the >>>>opponents. >>>> >>>>Did you consider to evaluate this information or do you think that this >>>>information is not important? >>>> >>> >>>I do this for some important special cases. Not in the general case. It's hard >>>for me to guess how productive that would be. >>> >>> >>>>I think that evaluating expensive information in part of the cases is probably >>>>the best practical idea. >>>> >>>>Based on my understanding Rebel is using that idea when it evaluates every node >>>>before qsearch by full evaluation and use lazy evaluation after it when the lazy >>>>evaluation can miss only factors that were not relevant before the qsearch. >>>> >>>>Do you use a similiar idea? >>>> >>> >>>No. >>> >>>You are confusing between the evaluation elements and its result. Both are >>>important, but it's still true that your evaluation of a position can use a lot >>>of smart and correct elements and be totally off, and it is equally true that it >>>can be right though neglecting a lot of important stuff. >>> >>>Amir >> >> >>It seems like you and Christophe have some tricks up your sleeve. He's been >>making comments like this for some time about his new 'Fugu' thing. It looks >>like I'm going to have to do some serious thinking :) >> >>anthony > > > >The basic thinking with Fugu is that I'm fed up of evaluating every position. I >want Chess Tiger to be able to understand which positions do not need more than >a pure material evaluation, and which positions must be evaluated positionally >very precisely. > >Another idea is to have an engine that performs two searches at the same time: a >very deep, full speed tactical search, and a less deep, very slow positional >search. The problem is what to do with the two results when they differ... :) > > > > Christophe Look at Shaeffer's stuff on Sun Phoenix. He had problems getting reasonable efficiency on a distributed search with an old 10mbit ethernet LAN, so he split the system into two parts, one that searched normally, one that did a fast tactics-only search. And he reached the same conclusion. What to do when they disagree. Or when the positional search says "play X" and the tactical search says "X sucks". :) I don't like the concept myself, but perhaps it can work.
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