Author: David Rasmussen
Date: 05:38:37 01/31/02
Go up one level in this thread
On January 31, 2002 at 07:56:21, Albert Silver wrote: >>Say 200K is good for 8 plies average, being 1000 x faster with a branching >>factor of 4 gives: 4x4x4x4x4 = 1024 -> 5 extra plies. >> >>So with 200M NPS you might be able to search 13 plies brute force in best case. >> >>Subtract a couple of plies (1 to 3) for the way DB did singular extensions and >>the picture fits, that is: DB was searching 10-12 plies as the log files >>confirm. >> >>This 12(6) isn't 18, you must have misunderstood its meaning. >> >>Ed > >I will add this, as I cannot comment on the numbers and math presented. I have a >lot of trouble believing Kasparov would go down to a program hitting only 10-12 >plies in a 6-game 40/2h match. Either it is amazingly smart with a super eval, >which all evidence suggests it had serious tuning issues with, or it is doing >some very deep calculating. > > Albert DB search had smart extensions (esp. singular extension) which made it tactically stronger than a 12-ply search might suggest. Also, if it is true that they avoided a lot of forward pruning (did they have null move?), their 12 ply counts for more than a modern heavily forward pruned 12-ply search. I don't know. Deep Blue might have been able to search to 18 ply in the middlegame, but then they had more pruning than I thought. An optimal ordered alpha-beta tree to 18 ply with 40 moves avg. without any smart pruning etc. cannot be done even with 200 Mn/s, I think. I might be wrong. /David
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.