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Subject: Re: Position Evaluation vs Selective Search

Author: Daniel Kang

Date: 11:30:04 11/20/00

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On November 20, 2000 at 13:13:21, Bo Persson wrote:

>On November 20, 2000 at 12:14:57, Bob Durrett wrote:
>
>>On November 20, 2000 at 11:55:10, Bo Persson wrote:
>>
>>>On November 20, 2000 at 11:06:46, Bob Durrett wrote:
>>>
>>>>Would it be possible to evaluate a position so well that only one next move
>>>>would need to be considered?  In that case, "selective search" would not involve
>>>>any selection at all [i.e. nothing to chose between].  The "selection" would be
>>>>done during the position evaluation.  In the limiting case, only ONE line would
>>>>need to be evaluated, except in the cases when two or more moves were found
>>>>[during the position evaluation] to be of equal value.
>>>
>>>If it was possible, you would have solved chess!  :-)
>>>
>>>Just let the program run from the start position, and see if it comes up with
>>>e2-e4 or d2-d4 as the optimum opning. Repeat for 40 plies and you end up in a
>>>check mate for white (or a draw??).
>>
>>You are assuming that one or the other of 1.e4 or 1.d4 is the better move.
>>Maybe not a valid assumption!
>
>Of course we don't know for sure, as the evaluator isn't finished yet. I would
>be *very* surprised if it was 1.a3 instead.
>
>>Incidentally, the position evaluation software may have to declare two or more
>>moves "equal" if they appear to be reasonably close.  How "reasonably" would be
>>defined in this case would be up to the programmer.
>>>
>
>My point was supposed to be that the current programs already *do* this
>evaluation, by doing a lot of calculations for each potential move from the
>position. The calculations are called "search".

I'd also like to add that this characteristic (looking at all moves rather than
blindingly following their intuition to limit the search to a couple of good
moves) is probably a strength of computer programs rather than a weakness. The
reason why humans rely on pattern matching rather than searching for move
selection is because their searching capacity is severely limited, not because
searching is an inferior method. In some sense, a human brain is a massively
parallel super-duper fault-tolerant computer specialized for pattern
recognition, yet to be matched in power by silicon-based number crunchers. I
just don't think it's a sound idea to imitate the human process, when current
methods have already yielded programs that outplay almost all humans, with
machines far less sophisticated than brains of even the dumbest humans.

Dan.




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