Author: Robert Hyatt
Date: 18:33:10 02/02/01
Go up one level in this thread
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. :)
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