Author: Uri Blass
Date: 13:37:13 05/27/02
Go up one level in this thread
On May 27, 2002 at 14:23:28, Robert Hyatt wrote: >On May 27, 2002 at 12:33:55, Sune Fischer wrote: > >>On May 27, 2002 at 11:58:38, Robert Hyatt wrote: >> >>>On May 27, 2002 at 06:14:38, Sune Fischer wrote: >>> >>>>On May 27, 2002 at 05:52:21, José Carlos wrote: >>>> >>>>> If I understood you right, you can simple put this on top of AlphaBeta() and >>>>>QSearch(): >>>>> >>>>> if (ply >= MAX_PLY) return Eval(); >>>>> >>>>> With 'ply' being the current depth, that you increment on every MakeMove() and >>>>>decrement on UnMakeMove(). >>>>> >>>>> José C. >>>> >>>>Yes, I guess that would work, technically. >>>>But having a check like that in the alpha-beta and the qsearch is all too often >>>>just a waste of time. >>>>I would like to solve the problem at the root if possible. >>> >>>I don't see how to do it at the root. If you do an N-ply iteration, how would >>>you know at the root how many extensions will "fire" so that you can be sure >>>that N + extensions <= MAXDEPTH??? >> >>If there is a limit on the number of extensions, then there you have it. >>Isn't it normal to limit the extensions to avoid explosions in certain >>positions? >> >>-S. > > >Yes. But how many? IE I allow 1 ply of extension for every ply of search, >up to some ply limit. Then I cut it back to 1/2 ply of extension for each >ply of search beyond that point. But a 20 ply search _could_ extend on >every ply.. That could take you to nearly infinite depth since each extended >ply could also extend a ply... The assumption that each extended ply could also extend a ply is wrong. If you allow a ply of the extension for every ply in the first 20 plies and 1/2 ply of extensions later then in the first 20 plies 1 ply does not have to reduce the depth but in the next plies every ply must reduce the depth by at least 1/2 ply. It means that you cannot have lines of more than 60 plies before qsearch. The first 20 plies are not going to reduce the depth but the next 40 plies are going to reduce the depth from 20 plies to 0 plies. Uri
This page took 0.01 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.