Author: Uri Blass
Date: 23:21:32 11/15/03
Go up one level in this thread
On November 16, 2003 at 01:29:52, Timothy J. Frohlick wrote: >To get to 14 ply with 11 to 12 good moves per ply would require a million >billion choices to be searched. 11 to 12 good moves per ply is only your imagination. alphabeta means that the program usually searches only 1 option in the even or the odd plies. Even the branching factor of tscp is smaller than 11 and I think that it is 7 and having better order of moves including using hash tables should help significantly. There are only 86,400 seconds in a day. Full >exhaustive searches to 14 ply could not be done on todays PCs. Wrong. I believe that branching factor of 5 is possible to achieve even without pruning(suppose even that only 6 is possible) 6^14<10^11 if you search 10^9 nodes per second you can get 14 plies brute force in 100 seconds(not that I think that it is good strategy). Only 31 moves >could be made in one year if a machine were searching at billion positions/sec. I do not understand it. > >Selective search which involves massive pruning of the search tree chooses only >three to five best first moves and examines the best responses again >selectively. Much less computer power is needed. > >Most GMs select the one best move depending on their analysis of the board >position and their memory of similar/same positions. The one best move approach >also depends on the attacking plans of the GM. No GM's look at more than one move and at more than one line when they analyze. > >The program that the article dreams about is not similar to today's PC programs. >It does not filter most of the choices in the search tree. > >TJF I do not know about which article you are talking. The poster said that there is an article and did not give a link and I am too lazy to search for it. > > >On November 15, 2003 at 23:47:04, Derek Paquette wrote: > >>This is a very ignorant question coming from me, >>but I'd love to hear the answers, it is bugging me. >> >>Ok, hypothetical question, Deep Junior 8 is playing against kasparov... >>it is a difficult board position, around 7 ply the computer should be coming >>across the correct move, there is only 1 correct move to play without a lose >>along the road... >>now if DJ8 is filtering at 99.99999% of the moves, >>why would it matter if it had quad 2.8ghz chips, or even 8 chips... >>if its not seeing the move, why would it at 22ply suddenly see it? Why not? There are moves that you need many plies to see them. >> >>on the x3d site there is an excellent article, and it says, a definate way to >>beat a super grandmaster is to build a machine running at 1 billion positions a >>second, and have it search to only 14ply, making thoroughness over filtering and >>deep looking a priority... >>so can someone explain to me why faster hardware makes a difference, if even my >>home pc can look at ply 18 with deep junior... When Junior says depth 18 it does not mean 18 plies. 9-36 plies dependent on the line is more accurate. Uri
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