Computer Chess Club Archives




Subject: Re: knowledge and blitz; search and long games

Author: Vasik Rajlich

Date: 14:08:34 02/15/06

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On February 15, 2006 at 10:16:29, Uri Blass wrote:

>On February 15, 2006 at 10:04:28, Vasik Rajlich wrote:
>>On February 15, 2006 at 03:07:50, Joseph Ciarrochi wrote:
>>>I have a naive question...
>>>in my understanding, Fruit has excellent search efficiency but not huge amounts
>>>of knowledge. In contrast, Fritz 9 and Rybka have substantial knowledge. If you
>>>can trust Rybka's depth outputs, it does not seem to be as quick at getting to
>>>deeper plys.
>>>I have observed that Fruit 2.2.1 tends to play poorly at blitz and improve
>>>steadly with long time controls, with it being an absolute god on the longest
>>>time controls (SSDF). In contrast, both rybka and fritz 9 play blitz well.
>>>do programs with more knowledge tend to play blitz better? Knowledge is kind of
>>>a quick, heuristic way of making a decision about what is likely to work. It
>>>presumably can come into play very quickly. In contrast, search takes time.
>>>However, it does discover when the knowledge is not useful (i.e., when the
>>>knowledge heuristic is inconsistent with the concrete variations uncovered by
>>>search; e.g., doubled pawns may generally be bad (knowledge heuristic), but in
>>>some situations can be quite good)
>>>is my reasoning correct? Maybe it would help for me to understand what
>>>constitutes "knowledge" in a chess program. I always presume its things like
>>>"doubled pawns are often bad" or two bishops are good, or it is often good to
>>>push pawns and have space..
>>We need to keep our terminology straight.
>>Chess knowledge (in the context of computer chess) is what makes a program play
>>well. At standard time controls, Fruit probably has a tiny bit more chess
>>knowledge than Fritz and Hiarcs.
>>You can also talk about the complexity of a chess program. Hiarcs is probably
>>the most complex of the above three, and Fruit the simplest. Shredder is another
>>complex program. I suspect that the more complex programs are better at faster
>>time controls.
>I do not think that you are right here because fruit1.0 was relatively better at
>faster time control and it was not a complex program.
>better order of moves can make the program better at slower time control and
>better order of moves may be a result of complex algorithm to sort the moves.

It's certainly not a rule, more of a trend. The more complex programs tend to do
more stuff at the tips, while the simpler programs prefer to just "search
through it".


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