Author: Uri Blass
Date: 07:35:49 10/23/00
Go up one level in this thread
On October 23, 2000 at 10:06:31, walter irvin wrote:
>On October 22, 2000 at 19:50:42, Uri Blass wrote:
>
>>On October 22, 2000 at 18:04:35, Thorsten Czub wrote:
>><snipped>
>>>ok - IMO what christophe has done is THE FIRST STEP.
>>>He had made tiger into a gambit-tiger who is not longer
>>>searching for SOMETHING in the tree, hoping to find anything,
>>>but to direct the program into chaos, into action, into
>>>the mirror-world where positions are not EXACT and also
>>>it does not interest how the score is, but it interest
>>>what you can make out of the position: i mean: the chances
>>>of a position.
>>
>>I do not believe it
>>GambitTiger like other programs plays the move with the highest score.
>>
>>There are sometimes big positional scores for king attack when other programs do
>>not have the big positional scores and are based mainly on material scores but
>>it does not change the fact that gambit plays the move that gives the highest
>>score from gambit's point of view.
>>
>><snipped>
>>>For a classical program, to keep the search fast, the evaluation at each
>>>node must, of necessity, be brief. This evaluation is usually no more
>>>than a weighting given for each piece on each square (for example a
>>>knight might be worth 3.3 pawns on centre squares and 2.9 pawns on edge
>>>squares) and evaluation of the pawn structure for doubled pawns, passed
>>>pawns etc.. The classical pre-processing function looks for themes in
>>>the position and adjusts the square weightings accordingly - for
>>>example, if a knight is attacking a square next to the king, then
>>>increase the weighting for all the squares that the queen could
>>>cooperate with the knight in making a king attack, increase the knight
>>>weighting to keep it on the original square, increase other cooperating
>>>piece weightings and so on. There is no doubt that this approach works
>>>but it cannot be the way forward. Pre-process ing knowledge becomes more
>>>stupid with increasing search depth, as positions deep in the search
>>>tree becomes more removed from the assumptions of the original position,
>>>the square weighting adjustments become more irrelevant (why weight the
>>>squares for the queen after the cooperating knight has been removed from
>>>the board ?- but the classical paradigm doesn't understand that !). I
>>>call this type of search Artificial Stupidity (AS). Since all the
>>>current programs operate in this way, ELO grading lists and inter-program
>>>tournaments are no more than a reflection of the partially-sighted
>>>playing the blind, whose AS algorithm is most efficient, but it is not
>>>chess.
>>
>>I know that a lot of chess programs do not operate in this way.
>>Chris says that programs use only preprocessor and piece square tables+pawn
>>structure evaluation.
>>
>>It is not close to be right.
>>
>><snipped>
>> >Dynamic knowledge v. Combinational knowledge
>>>============================================
>>>
>>>Oxford Softworks CCS2-v9.0
>>>White: CCS2 486/33
>>>Black: Genius2 486/33
>>>Venue: 1 minute per move
>>>Comment: 1-0
>>>
>>>1. e4 e6
>>>2. d4 d5 1
>>>3. Nc3 Nf6 3
>>>4. Bg5 Be7 5
>>>5. e5 Nfd7 8
>>>6. h4 Bxg5
>>>7. hxg5 { CCS2's opening book ends }
>>> .... Qxg5
>>>8. Nf3 Qd8 { Genius2's opening book ends }
>>>9. Bd3 h6
>>>10. Qd2 { CCS2's dynamic knowledge - preventing O-O because
>>> of the threat of Rxh6 }
>>> .... c5
>>>11. Nb5 O-O { Catastrophic - any reasonable club player can
>>> see this move is a disaster, but Genius2 has no
>>> dynamic knowledge, there is no immediate mate so Genius2
>>> thinks all is ok ! }
>>
>>The position after Nb5 is a good test position
>>The target is to avoid 0-0
>>[D]rnbqk2r/pp1n1pp1/4p2p/1NppP3/3P4/3B1N2/PPPQ1PP1/R3K2R b KQkq - 0 1
>>
>>Some programs like Crafty may need some minutes but I believe that on fast
>>hardware all the top programs have no problem to avoid 0-0.
>>
>>Part of them like Fritz5.32 never consider 0-0 as best.
>
>
>if you really believe what you are saying then this statement must be true .
>1.there is not much use for chess programmers anymore because all you have to do
>is tweak the eval and presto 150 elo .
Tweaking the evaluation is not simple and we need chess programmers to do it.
I also did not say that changing the search rules is not productive.
>
>2.that crafty should be as strong or stronger than gamit tiger with the right
>eval changes .
I did not say it.
Crafty has different rules of pruning and extensions.
I did not say that Crafty is identical to Chess tiger except evaluation.
Uri
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