Author: Derek Paquette
Date: 06:29:07 11/16/03
Go up one level in this thread
On November 16, 2003 at 02:21:32, Uri Blass wrote: >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 If the machine is filtering so much, what does extra hardware do for it neway if its just not going to see the position? Why after 5 minutes would it see the right position that it should see after say 7 ply, when in 30 seconds it couldn't...it already left that move possibility in the dust... that is my question, I see it all the time, after 13 minutes a program finds such and such a move...but the actual move was only 7ply deep..but it took 45 minutes to find it. etc. I don't understand...does a computer keep looking back and going through different moves from the start if it doesn't find anything positive??
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