Author: Ricardo Gibert
Date: 12:46:58 12/05/00
Go up one level in this thread
On December 05, 2000 at 15:21:02, Miguel A. Ballicora wrote: >Before the question, a little background and an aknowledge. >I am writing a program that plays chess mainly for fun. I started 3-4 years >ago and I could not keep up but now I want to continue. I made it to work, >and I can play a game against it (in fact, it plays much better >than I would have predicted being so basic). I like to thank most of the >people in this forum because the little I know I learned it from one chapter >in the enciclopedia of A.I. and mainly from >reg.games.chess.computer and their archives in www.dejanews.com 3-4 yrs ago. >Most of the authors of those messages are writing here now. > >My program generates the moves using bitboards. It does what it is called >"aspiration search" and iteration deepening, >I sorts the move by something similar to MVV/LVA, it uses history tables, i t >does not do "killers" yet. It has a transposition/refutation table, I use the >store moved trying to make a cutoff first (>=beta). It has a rudimentary >evaluation function that takes into account material, movility >terms and rudimentary pawn structure (isolated and double pawns). >I extend teh search when I found a check or a recapture. Also when >It looks like there could be a perpetual. It detects draw repetition. >I also implemented null move (I am using what I understand people call it R=2) >The program is slow (30-40 knps in AMD K-2 400 mhz) and my "to do list" >is huge. I am happy because it is "running" but I feel that most of >the code should be updated, debugged, improved, modified, profiled, optimized >etc. etc. >(any suggestion about what my next step should be will be greatly appreciated) >My plans now are to improve the search and the tree size. > >Too much of an introduction. My question is: >How do you realize that your hash table is efficiently coded? >from the initial position into ply 7 or 8 I have ~4-5% of the nodes >hit in the hash table (position was found) but only ~10% of those hits (0.5% >total) can be used to return a value (depth stored is >= than depth). >Are these numbers reasonable? >If I use two tables, one for overwriting always and the other to overwrite >only if depth >= depth stored it does not change much. > >If the numbers are not reasonable, what would you try to change or debug? > >Regards, >Miguel How about some sample search output on test positions from your program with data on PV, nodes per second, depth, total nodes, etc. People will get a better idea of what to suggest with this information. Also, a game score would be helpful. Interesting too.
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