Author: martin fierz
Date: 01:36:40 02/17/04
Go up one level in this thread
On February 16, 2004 at 19:12:54, Will Singleton wrote: >On February 16, 2004 at 17:11:57, martin fierz wrote: > >>On February 16, 2004 at 16:06:00, Robert Hyatt wrote: >> >>>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... >> >>i believe it's fundamentally wrong to force computers into some human >>straight-jacket. we have our capacities, the computers have theirs. ><snip> > >Yes, now. But think about how strong a computer might be if it could emulate >the human approach to chess. Pattern-recognition and extrapolation, at which >the brain can excel, are probably the best way to limit tree size (at least >better than what we do now). As computers get faster, with access to huge >memory, the standard minimax with alpha/beta approach will improve. But the >real breakthrough will occur when our primitive knowledge of brain function >becomes better understood, and we can take advantage of vast memory and >processing speed to replicate, and then improve upon, the human approach to >chess. why should a computer emulate the human approach to chess? not everything in nature is perfect... are our aeroplanes equipped with big feathery flapping wings? if we find a better solution, we should use it. chess computers can do many things the best human players are quite uncapable of, and sacrificing this kind of power seems wrong to me (and you would be sacrificing it if you wanted to build in sophisticated pattern recognition in a program, slowing it down by many powers of 10...). on another note, there was a lot of hype in the press and scientific journals about a checkers program by fogel and chellapilla, called blondie 24. it was basically a normal alpha-beta searcher, but it had a neural network as evaluation function, which it self-tuned. it plays an absolutely pathetic game of checkers, and i'd bet that i can write an evaluation function of maximum 100 lines of C code which is far better than that of blondie - and with that i mean that my version would be better when searching to the same depth. of course, my version would also badly outsearch blondie because computing NN stuff is very expensive. why am i mentioning this? this is at least partly an effort to emulate the human way of thinking (at least according to the authors). in this case, it simply doesn't work. cheers martin > >But at that point, will computers want to play chess? :) > >Will
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