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Subject: Re: Intelligent software, please

Author: Ed Schröder

Date: 04:48:25 11/26/01

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On November 26, 2001 at 07:11:09, Otello Gnaramori wrote:

>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:
>>>I think that the following is the article mentioned by Victor :
>>>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:
>>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
>>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.
>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"

The statement is still valid IMO. In comp-comp search is a much more dominant
factor than in human-comp.

>Thanks in advance.

You are most welcome.


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