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Subject: Re: Algorithms vs. knowledge - What to do next?

Author: Robert Henry Durrett

Date: 13:18:42 06/04/02

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On June 04, 2002 at 16:09:26, Uri Blass wrote:

>On June 04, 2002 at 15:28:03, Robert Henry Durrett wrote:
>
>>On June 04, 2002 at 15:11:31, Uri Blass wrote:
>>
>>>On June 04, 2002 at 14:35:08, Robert Henry Durrett wrote:
>>>
>>>>On June 04, 2002 at 13:12:14, Uri Blass wrote:
>>>>
>>>>>On June 04, 2002 at 10:49:00, Vincent Diepeveen wrote:
>>>>>
>>>>>>On June 04, 2002 at 08:54:57, José Carlos wrote:
>>>>>>
>>>>>>What i read in Dann's words is he is more believing in search
>>>>>>rather than the knowledge. If that's the case then i think he is
>>>>>>wrong.
>>>>>>
>>>>>>I do not see how to easily improve search either.
>>>>>>
>>>>>>Let's compare diep 1998 with diep 2002.
>>>>>>
>>>>>>Of course when takling about eval we are quickly finished. It's
>>>>>>way bigger now and way better. Let's just compare the SEARCH now.
>>>>>>
>>>>>>DIEP 2002: 8 probes hashtable, nullmove R=3 always, 2 killermoves,
>>>>>>complex move ordering but not that much changed last years,
>>>>>>some complex extensions but those
>>>>>>do not contribute much to the game, at most solve testsets a bit
>>>>>>sooner. quiescencesearch is pretty complex but compared to 1998
>>>>>>very simple as i do way more there now.
>>>>>>
>>>>>>Now DIEP 1998, this is a very complex search. First of all i did
>>>>>>all kind of efforts to not get too undeep. It was getting not enough
>>>>>>depth at tournament level to even see basic tactics which i see.
>>>>>>
>>>>>>So i did all kind of difficult forward pruning. Also weird things
>>>>>>like special killertables were used. Special information was gathered
>>>>>>in order to search less last few plies and qsearch was way more
>>>>>>limited. Nearly no check was extended in the main search, because
>>>>>>this was to expensive. Hardly any extension was done there.
>>>>>>
>>>>>>Of course it was not a parallel engine, but that's about only thing
>>>>>>which has become more complex in search, though it in fact is still the
>>>>>>same type of search.
>>>>>>
>>>>>>In short my search has become much simpler, especially when talking
>>>>>>about quiescencesearch. I'm not blinking with my eyes now to have
>>>>>>a bigger overhead there!
>>>>>
>>>>>Better search rules does not mean always more complex rules.
>>>>>
>>>>>The right rules also may be dependent on the evaluation and I think that this is
>>>>>a good reason after getting to the level of programs like my program that is in
>>>>>similiar level to the Baron to start with improving the evaluation(otherwise you
>>>>>may waste time on implementing some rules that are good for your stupid program
>>>>>when you will need to change them when you have a better program).
>>>>>
>>>>>I do not like the idea of writing a lot of evaluation code for a lot of cases
>>>>>and I think that a better idea  is to think about few rules that generalize a
>>>>>lot of cases.
>>>>>
>>>>>
>>>>>Uri
>>>>
>>>>Is it fair to infer from the above that you are doing the following?
>>>>
>>>>(1)  First evaluate a position,
>>>>
>>>>(2)  Then chose a small set of "search rules" from a large set of available
>>>>rules [available in your software], with this selection based on the findings of
>>>>the position evaluation,
>>>>
>>>>(3)  And, finally, perform a search from that position using the selected
>>>>"search rules"?
>>>>
>>>>Bob D.
>>>
>>>No.
>>>
>>>When I said that the right rules may be dependent on the evaluation I meant that
>>>it is possible that the optimal search rules after improving the evaluation is
>>>different(for example it is possible that null move with R=2 is better for a bad
>>>evaluation when null move with R=3 is better for better evaluation).
>>>
>>>I do not like to waste time about testing when the new search rules may be worse
>>>for the new evaluation.
>>>
>>>What you suggest may be a good idea but today there is only a small set of
>>>search rules and not a large set of search rules.
>>>
>>>Uri
>>
>>Thanks.
>>
>>What I was trying to do is to better understand which positions are evaluated
>>[only the position which occurs immediately after a move? Other positions
>>occurring during search?], the form/format/content of the evaluation findings,
>>and how these might be processed or utilized.
>>
>>Probably different for each chess engine?
>
>Yes
>Things are different for different engines
>
>I do not want to discuss about what Movei does but there are a lot of free
>programs with source code.
>
>I believe that Movei does some things that no other free program does but I do
>not know because I am too lazy to read all the source codes and I cannot ask
>because I do not want to tell my ideas.

Well, I guess my ideas are free, since I am not in competition.

But you get what you pay for.  :)

Bob D.

>
>Note that Movei is clearly weaker than the best free programs because the weight
>of the good ideas that Movei does not use is clearly bigger than the weight of
>the good ideas that the best free programs do not use.
>
>Uri



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