Author: Otello Gnaramori
Date: 04:11:09 11/26/01
Go up one level in this thread
On November 26, 2001 at 05:15:55, Ed Schröder wrote: >On November 26, 2001 at 04:08:27, Otello Gnaramori wrote: > >>On November 26, 2001 at 03:48:30, Ed Schröder wrote: >> >>> >>>I have no idea Victor is talking about, Claudio has written some very >>>interesting topics about computer chess, see: >>> >>>http://www.rebel.nl/claudio5.htm >>>http://www.rebel.nl/claudio4.htm >>>http://www.rebel.nl/claudio3.htm >>> >>>Ed >> >>I think that the following is the article mentioned by Victor : >> >>http://www.rebel.nl/claudio4.htm >> >>Infact it is written at a certain point : >>(...) >>According to Ed's announcement in this web page, several programmers are facing >>the task of suppressing important amounts of programming code in the evaluation >>function, to achieve more speed and conquer their computer competitors by the >>brute force of tactical calculation. >>(...) > > >That is a complex subject. At the time (about 2 years ago) I have written a >page about the issue to explain a bit. The topic was called "Chess in 2010" >and its contents are found on: > >http://www.rebel.nl/ches2010.htm > >The page is still worthwhile reading but in the meantime my thoughts about >this have a bit evolved. That is that you really can throw out unnecessary >chess knowledge with the emphasis on "unnecessary". > >Some specific chess knowledge through the years become out-dated due to the >speed of nowadays computers. An example: In the early days of computer chess, >say the period 1985-1989 I as hardware had a 6502 running at 5 Mhz. Rebel at >that time could only search 5-7 plies on tournament time control. Such a low >depth guarantees you one thing: horizon effects all over, thus losing the >game. > >To escape from the horizon effect all kind of tricks were invented, chess >knowledge about dangerous pins, knight forks, double attacks, overloading >of pieces and reward those aspects in eval. Complicated and processor time >consuming software it was (15-20% less performance) but it did the trick >escaping from the horizon effect in a reasonable way. > >Today we run chess program on 1500 Mhz machines and instead of the 5-7 plies >Rebel now gets 13-15 plies in the middle game and the horizon effect which >was a major problem at 5 Mhz slowly was fading away. > >So I wondered, what if I throw that complicated "anti-horizon" code out of >Rebel, is it still needed? So I tried and found out that Rebel played as >good with the "anti-horizon" code as without the code. In other words, the >net gain was a "free" speed gain of 15-20%, thus an improvement. > >One aspect of chess programming is that your program is in a constant state >of change due to the state of art of nowadays available hardware. I am sure >a Rebel at 10 Ghz several parts of Rebel need a face-lift to get the maximum >out of the new speed monster. > >One recent example: Century 4 eval is more speculative than previous versions. >Why? Because I believe (confirmed by my test results) that the program can >handle it because of the mixture of smart search and fast hardware. A deep >search simply filters out most of the "too speculative errors" of eval and >the net result is a better, even more attractive chess engine. > >Ed Thanks Ed for your explanation. I would like to ask you one more question : Do you think that in light of the recent developments this statement coming from the rebel site is still true ? : "We have tried to explain that adding new chess knowledge which makes a chess program a better positional player could lower the playing strength in the comp-comp area and that removing chess knowledge which makes a chess program a lower positional player on the other hand could improve its performance in the comp-comp area" Thanks in advance.
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