Author: Robert Hyatt
Date: 09:29:52 01/19/04
Go up one level in this thread
On January 19, 2004 at 12:11:30, Tord Romstad wrote: >On January 19, 2004 at 11:43:21, Sune Fischer wrote: > >>A while back I ran lots of test positions and compared the PVs between the two >>methods. >>What I generally saw was that they were identical, only the hash extracted PV >>usually were a few moves longer. > >I extract all my PVs from the hash table. I am not sure I agree with >your observation that the hash extracted PVs are usually longer, but I >agree that they are *sometimes* longer. > >Today Leo helped me discover an obscure bug related to this. The >maximum search depth in Gothmog is 60 plies, and my PV[] array has >60 entries. The fact that extracting the PV from the hash table >could cause a PV of length greater than 60 plies had never passed >my mind until Leo sent me a debug file from a game where Gothmog >crashed directly after printing out a 61-move PV. :-) I assume you are eliminating cycles when you do this? IE you can reach a path like this: a-b-c-d-e-f-g-h-i-j-k-e If you don't stop, you can now cycle forever and blow _any_ array size you want. I used to expand my PV by probing the hash after an iteration ended, and I had to handle this case myself... > >Tord
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.