Author: Gian-Carlo Pascutto
Date: 03:02:09 08/29/05
Go up one level in this thread
On August 27, 2005 at 23:30:52, Robert Hyatt wrote: >On August 27, 2005 at 15:36:15, rasjid chan wrote: > >>On August 27, 2005 at 10:09:21, Jon Dart wrote: >> >>>> So this mean we don't need to keep pv[][] if we have hash tables (it is >>>> like double accounting). >>> >>>I think this is false, given you have a finite size hash table and must >>>eventually replace something. I have some experience: I used to retrieve pv from >>>the hash table but now use a pv array and back up the scores. >>> >>>--Jon >> >>They tell me so and I begin to doubt. Maybe as Dr Hyatt says, backup the pv. >>It may be best to be simple as I don't yet know how hashing twists and turns >>within. >> >>Rasjid > >Just remember this. While searching the PV, _after_ you search a move on the PV >path, you do a lot of other searching. Any of which can overwrite the PV move >so that you get no move at that point, and a resulting short PV. The "back up" >method has no significant cost associated with it, since it is not done very >often in a PVS-type search... > >If you really don't care, the hash table approach works much of the time, and >does have zero overhead. The array backup method has a finite but small >overhead. I find that avoiding the short PVs helps in testing and debugging, >but in real games is irrelevant with respect to the game outcome... What about setting a flag in the hashtable that it is a PV move and should not be overwritten? I never did this, but thinking of it, why not? -- GCP
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.