Author: Dann Corbit
Date: 17:42:27 12/14/05
Go up one level in this thread
On December 14, 2005 at 19:50:02, Uri Blass wrote: >On December 14, 2005 at 19:25:38, Dann Corbit wrote: > >>On December 14, 2005 at 19:18:28, Uri Blass wrote: >> >>>On December 14, 2005 at 18:53:21, Dann Corbit wrote: >>> >>>>On December 14, 2005 at 08:00:00, Vasik Rajlich wrote: >>>> >>>>>On December 14, 2005 at 04:44:15, Steve Maughan wrote: >>>>> >>>>>>Vasik, >>>>>> >>>>>>>The problem is when the hash entry ages. >>>>>> >>>>>>This is easy to get around - just store the distance to mate from the *position* >>>>>>(i.e. not the root) in the hash table. >>>>>> >>>>>>In pseudo code: >>>>>> >>>>>>procedure push_hash(position) >>>>>>begin >>>>>> if winning_mate_value_in_hash then >>>>>> hash_draft_depth += position's_ply_from_root >>>>>> else if losing_mate_value_in_hash then >>>>>> hash_draft_depth -= position's_ply_from_root >>>>>> store(position) >>>>>>end; >>>>>> >>>>>>procedure probe_hash(position) >>>>>>begin >>>>>> if found_in_table(poistion) then >>>>>> begin >>>>>> get_hash(position) >>>>>> if winning_mate_value_in_hash then >>>>>> hash_draft_depth -= position's_ply_from_root >>>>>> else if losing_mate_value_in_hash then >>>>>> hash_draft_depth += position's_ply_from_root >>>>>> end >>>>>>end; >>>>>> >>>>>>I hope this helps! >>>>>> >>>>>>Regards, >>>>>> >>>>>>Steve >>>>> >>>>>Steve, >>>>> >>>>>thanks, I guess this also works - although it's a bit dirty. >>>> >>>>What's the other way to do it? >>> >>>see my post in >>> >>>http://www.talkchess.com/forums/1/message.html?470096 >> >>Can't the same position (therefore) have a huge number of different scores then >>(depending on where we saw it in the tree)? >> >>Tbis way seems more complicated to me. > > >You are right. >I did not think about that problem. > >I do not use hash for pruning so I have no experience with that problem. I am curious about why you do not use hash for pruning. The chances of collision are very low and you can detect that as well. Are you worried about losing the pv?
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