Author: Uri Blass
Date: 16:50:02 12/14/05
Go up one level in this thread
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. Uri
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