Author: Alvaro Jose Povoa Cardoso
Date: 00:54:00 02/03/01
Go up one level in this thread
On February 02, 2001 at 21:33:10, Robert Hyatt wrote: >On February 02, 2001 at 14:42:23, Alvaro Jose Povoa Cardoso wrote: > >>On February 01, 2001 at 18:37:48, Robert Hyatt wrote: >> >>>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.. >> >> >>That is exactly what I was talking about. When I get an EXACT hash hit the PV is >>cut short, and extending it from the hash table doesn't help much, I just get >>1-3 moves from the hash, perhaps there is something wrong with my program. >>Also, and in response to Dr. Robert Hyatt, I can´t execute the assignment >>because my program is the portuguese version of checkers. I hope you don't mind >>if I ask questions not related to the game of chess. >> >>Thank you >>Alvaro Cardoso > >That is a perfectly normal problem. My PV is often shorter than it should >be due to an EXACT hash hit. Nothing you can do about it, not that there >is anything wrong with it. > >And you can _still_ turn in your assignment on time. Checkers is perfectly fine >to test your hypothesis. :) I'll do the test and I will report the results soon. Thank you Alvaro Cardoso
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