Author: Anthony Cozzie
Date: 07:35:35 12/29/03
Go up one level in this thread
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.
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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