Author: Uri Blass
Date: 06:44:15 05/07/02
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On May 07, 2002 at 09:06:46, Sune Fischer wrote: >On May 07, 2002 at 06:24:19, Uri Blass wrote: > >>I read in bruce moreland's site about hash tables >>see http://www.seanet.com/~brucemo/topics/hashing.htm >> >>I try to use them first in my program only for better order of moves >>and I try to use the algorithm that is in that site >> >>I think that there is some misleading information there >> >>The function RecordHash includes recording the best move but when the depth is 0 >>there is no best move that was leading to the position. > >In cases where there is no move I store a zero-move, the old move has to be >overwritten anyway. > >>When I use hash tables only for better order of moves then it seems to be >>useless to record hash tables when the remaining depth is 0. > >Yes I think you are right, unless you also hash in the qsearch you would have no >idea what kind of result (exact or fail low/high) to store. > >>I also think that recording hash tables in the last plies is relatively >>unimportant at long time control and it may be even better not to try it if I >>use the scheme "always replace" because it is more important to remember the >>best moves in the first plies. >> >>Am i right? > >I believe Vincent said he hashes everything in Diep, if your eval() is very >large it may be worth it. A special HT for pawnstructure evaluation is very >commen. My evaluation is not very large. > >>I prefer to start with something relatively simple and to check that I have no >>bugs and only later to develop it to something more complicated and this is the >>reason that I use "always replace" > >Well start by making sure you key is not corrupted during search (I assume you >build it incrementally), nothing will work until that is in order. > >-S. I build it incrementally and I hope that it is not corrupted. I checked only in some positions that the key is the same every time I go back to the root. I found that it is slightly faster in few test positions but only something like 20% faster. In game against the previous version the previous version has a score of 7-3 with white It won the first 4 games(1,2 minutes/40 moves and drew the games 3,4,5 minutes/40 moves) positions out of book were always 1.e4 Nf6 or 1.d4 d6. I may repeat the games with opposite colors. Uri
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