Author: Robert Hyatt
Date: 15:37:48 02/01/01
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On February 01, 2001 at 16:27:29, Tony Werten wrote: >On February 01, 2001 at 14:19:25, Alvaro Jose Povoa Cardoso wrote: > >>Does any one tried to use just Upperbounds and Lowerbounds in hashing, ignoring >>ExactScore entries? >>My question has to do with the fact that if we use ExactScores we don´t get long >>PVs to feed in the next iteration, even if we extend PVs from hash. >>My testing shows that if we do not use ExactScore entries in the hash table, we >>end up with very long PVs that can be fed into the next iteration in order to >>aproximate the minimal tree. After all, ExactScores are rare compared to >>Upperbounds and Lowerbounds. >> >>Can someone comment on this? > >One of us is missing something. The PV is always exact. If you don't store >exact, you don't have a pv. I don't know what you get from the hashtable, but it >isn't a PV. > >I take my PV from hashtable and I (almost) always get a long pv, at least as >long as the search depth. > >Tony > >> >>Thank you >>Alvaro Cardoso He is talking (I think) about a PV that is cut short when you get an EXACT hash hit. IE in crafty, where a PV ends with <HT> which sometimes happens at ply=2/3/4 and results in a very short PV. I use internal iterative deepening to help search around this the next iteration, however..
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