Author: Vasik Rajlich
Date: 15:46:10 12/29/03
Go up one level in this thread
On December 29, 2003 at 10:35:35, Anthony Cozzie wrote:
>On December 29, 2003 at 09:04:44, Tord Romstad wrote:
>
>>On December 28, 2003 at 22:18:04, Anthony Cozzie wrote:
>>
>>>In my personal opinion: The time of such static tricks has passed. When people
>>>ran on a 386 and struggled to get 5 ply, extensions && pruning were critical.
>>>Top programs nowadays get 14 ply. The simple fact of the matter is that
>>>computers are almost perfect tactically. More depth now is purely for
>>>positional benefit. Right now I'm trying to _reduce_ my extensions, not add
>>>more :)
>>
>>By proceeding in the same direction, you will start adding reductions. :-)
>>
>>I disagree that computers are almost perfect tactically. In the comp-comp games
>>I see,
>>a high percentage of the games are decided by a tactical mistake by one of the
>>engines.
>>You may be right that the main importance of more depth is stronger positional
>>play,
>>but I don't see this as a reason to avoid using knowledge in the search. By
>>pruning or
>>reducing anti-positional moves with no tactical potential, you will search
>>deeper positionally
>>*and* tactically.
>
>In blitz, maybe. But at longer time controls even Zappa makes almost no
>tactical errors.
>
>>You also once again make the mistake of believeing that everybody is only
>>interested
>>in making their engines play well on super-fast hardware. Programming a chess
>>engine
>>that plays well on a fast, modern PC is so easy that it is almost boring. In my
>>opinion, it
>>is much more interesting to invent techniques which do not require extreme speed
>>of
>>computation in order to work.
>
>Depends on how you define "well". Better than a human? easy. Better than
>Crafty/Yace/Ruffian? more challenging.
>
>>>Thorsten and Ed have both said that Rebel plays better with the reductions off.
>>>The only engine on ICC that uses his reductions is Chompster, and I've seen
>>>chompster make errors on a 10 ply search that Zappa catches with a 6 ply search.
>>
>>When you start a sentence with "The only engine on ICC that uses ...", the
>>statement will
>>almost always be wrong, no matter how you complete it. Gothmog ("GothmogX" on
>>ICC)
>>doesn't use exactly the same reductions as Rebel, but it does many similar and
>>often more
>>aggressive reductions (for instance, I have no upper limit for the number of
>>reductions in a
>>single path). I'm sure you'll be able to find positions where Gothmog makes
>>errors in a 10
>>ply search which Zappa catches with a 6 ply search, but I also think it is
>>possible to find
>>positions where the opposite happens.
>
>First of all, for me and I think you chess programming is a hobby, not a job.
>We are free to do whatever we want: optimize for standard time controls and dual
>opteron, or 2 minute bullet on a cell phone, or for playing an interesting game
>of chess, or for being a good sparring partner for my grandmother, or whatever.
>Being the competetive person I am, I try to make a strong engine, so that is my
>viewpoint.
>
>Secondly, I am talking about strong chess programs. Commercials + top amateurs.
> Ruffian made a tactical error at Leiden 2003. 1 error. And we were all
>amazed because it happens so infrequently. When you get 14 ply, you just don't
>make mistakes. You have to win with eval/book.
>
>Third, my point was not to derogate Chompster or Gothmog, but simply point out
>that worst case performance is what matters. What do you think is stronger: 35
>14-ply searches and 5 8-ply searches, or 40 13-ply searches? That is the
>problem with all static tricks: Every now and again they are wrong, and when
>they are wrong your program can lose the game in one swift swoop.
Actually 35 14-play searches & 5 8-ply searches may well be stronger. It's often
worth some effort to play a few extra strong moves, even if they're not decisive
or even tactical in nature. That's why the top players are often ready to risk
mild trouble in order to play as accurately as possible. I remember in
Kasparov-Kramnik, Astana '2001, moves 12-18 took something like 3 hours, and
there weren't even queens on the board.
Vas
>
>I think it is possible to add 20-30 elo to your engine with static pruning.
>HIARCS and Shredder seem to have static pruning that more or less works. But I
>think it takes years to get right.
>
>anthony
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