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Subject: Re: Symbolic: The TNS (Thousand Node Search)

Author: Robert Hyatt

Date: 13:06:00 02/16/04

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On February 16, 2004 at 15:38:58, Uri Blass wrote:

>On February 16, 2004 at 14:43:48, Robert Hyatt wrote:
>
>>On February 16, 2004 at 10:31:03, Steven Edwards wrote:
>>
>>>Symbolic: The TNS (Thousand Node Search)
>>>
>>>The idea of limiting the cognitive search in Symbolic to under a thousand nodes
>>>is based upon psychological studies that suggest top level human chessplayers
>>>usually visualize between 100 and 1,000 positions per move in complex
>>>middlegames.  My personal time control upper limit preference for non-blitz
>>>chess is a minute per move, and so the resulting target figure for node
>>>frequency is about 20 Hz.
>>
>>I think you are starting off here using an unsound assumption.
>>
>>"100 to 1000 positions per move" is probably nowhere near right.  There is a
>>difference between a human mentally moving pieces around, and his comparing them
>>to pattern-recognition information that in itself is the result of searching
>>significant amounts of tree space.
>>
>>Who knows _what_ I actually do after thinking a few minutes and moving the
>>pieces around in my head, to decide 'this position is one I want to reach."  Did
>>my "static evaluation" fold in a bunch of past experiences via pattern matching?
>> IMHO picking some number like 1K is just picking a number like 1K, not that 1K
>>is more or less meaningful than 100 or 10K...
>>
>>
>>trying to quantify how many "positions" a human searches is pointless until we
>>know how a human really "searches".  To date, we have no idea.  this probably
>>won't change for many years, until all the marvelous abilities of the human
>>brain have been analyzed and understood.
>
>I think that it is not necessary to know how the human brain analyze and it may
>be possible to generate something better because humans do not do something that
>is close to optimal.
>
>Humans do a lot of mistakes and they use a lot lazy evaluation.
>When humans visualize positions they do not count exactly pawn structure of
>every position and other factors and their lazy evaluation may miss an important
>positional factor that they could see by looking at the relevant position for
>another second.
>
>Humans also do not have a perfect memory and they may analyze the same line
>again because they forgot that they already analyzed it or they forgot the
>result of their analysis.
>
>Uri


I wouldn't argue that point at all.  however, the original reason for choosing
"1000" was based on some perceived human ability to evaluate that many positions
(upper bound).  I think that concept is what is flawed.  Trying to do a good
program with only 1K nodes is an interesting goal.  But thinking that the 1K
number has something to do with human thought processes is probably incorrect.
I say probably because no one knows, just yet...



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