Author: Larry Griffiths
Date: 19:09:24 02/14/01
Go up one level in this thread
On February 14, 2001 at 14:06:03, José Carlos wrote: >On February 14, 2001 at 12:37:52, Larry Griffiths wrote: > >>On February 14, 2001 at 10:11:53, Carmelo Calzerano wrote: >> >>>On February 14, 2001 at 09:35:58, Larry Griffiths wrote: >>> >>>>Carmelo, >>>> >>>>I will dink around with the hash table some more and see if I can find a bug >>>>somewhere. >>>> >>>>Is this Fine 70? >>>> >>>>[D]8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - - >>> >>>Exactly ;-) >>> >>>Bye, >>>Carmelo >> >>Ok Carmelo, >> >>I did find a bug in my hash code and am getting upper_bound cutoffs now. >>I owe you one since I was about to give up on the hash table for a while. >>I ran the Fine 70 position using a 16meg hash table. My hash tables are >>28 bytes in size. >> >>My program goes 17 plys in 18 seconds without the hash table, >>and 19 plys in 6 seconds with the hash table. >> >>I noticed that Hardly any of the 16meg hash table was used. I am only using 1 >>slot per hash key, and maybe if I add/look at the next 8 slots I can get some >>more entries in the hash table and go deeper on plys. > > I don't know what you mean with the slots thing (though I figure), but I think >you may have a problem with the hash codes, because you're doing too slow in >this problem, and don't even fill 1 Mb of the hash... > > I may be wrong, but I think your hash codes are not different enough for >similar positions. > > José C. > Thanks for the information Jose. I generated my piece-square tables using random numbers and the hash-keys in the tables might not be different enough. I am using 64-bit hash-keys as 32-bit hash keys were producing lots of instances where different positions equated to the same hash-key. I think this caused my program to make some terrible moves so that is why I went to 64-bit hash-keys. I will try using some different hash-key generations schemes and then see what percentage of the hash-tables is used. Larry.
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