Author: Robert Hyatt
Date: 15:37:47 09/06/04
Go up one level in this thread
On September 06, 2004 at 13:14:36, Stuart Cracraft wrote: >On September 06, 2004 at 11:23:23, Richard Pijl wrote: > >>On September 06, 2004 at 10:48:00, Stuart Cracraft wrote: >> >>>On September 06, 2004 at 04:47:12, Alessandro Scotti wrote: >>> >>>>On September 05, 2004 at 22:12:35, Stuart Cracraft wrote: >>>> >>>>>I walk the PV until there is no further position. No limit. This can then >>>>>either be left in the hash table if you don't clear between searches >>>>>but like Bob, you should keep the PV entries and restore them in the >>>>>hash table before the next search whether or not you table-clear due to >>>>>potential changes. >>>>> >>>>>I don't do this. It's a simple fix. I don't know why I've delayed putting >>>>>it in. >>>> >>>>I don't either. But since I get my PV from the hash table, it's already there. >>> >>>Mine is already in there as well so I don't see why Bob said to >>>store it in the hash table after the last iteration unless Crafty uses >>>some different method to record the PV and has to store it in the hash >>>table prior to the next iteration. Why wouldn't it be in there already? >>>Does Crafty clear the hash table between moves? >> >>Reinserting (from a PV array) makes sure that the whole PV is in there for the >>next search. The PV positions could have been overwritten by other positions. >>Richard. > >But if you got it originally from the hash table in the first place at the >end of the last iteration, then they may already have been overwritten. >You would have to use an alternate method like triangular array to >store them, away from hash, then access that array and fill hash from >it prior to new iteration. That is the point. _I_ don't get it from the hash table in the first place, but I do want to make sure it is there at the start of the next iteration so that my move ordering (which always searches hash move first) will be correct. If you get it from the hash, you get bad/short PVs regularly. No need to re-insert them since what is already there is all you have anyway. But it does lead to PV problems to do it from the hash...
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