Author: Tord Romstad
Date: 11:09:19 08/17/03
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On August 17, 2003 at 04:27:06, Rudolf Huber wrote: >First scan you source files for occurences of alpha and beta. There are no alphas or betas left -- I rewrote search() and qsearch() from scratch when implementing MTD(f). I only have the single parameter (gamma), like in Aske Plaat's paper. >If you find any look hard and try to understand what you are doing there. In >mtd(f) there ist NO alpha and NO real beta. All the things (lazy eval?) >you do with alpha and beta are most likely wrong. Use the last score instead. What does the "last score" mean in the above sentence? >Also I think it is a good idea to keep it simple. Why not disabling >forward pruning and your "convergence accelerator" and first try to make >your mtd(f) implementation better than negascout. I agree entirely. This is basically what I have done (except that I have no negascout implementation to compare it to). I started with a very rudimentary full-width search without any extensions, reductions or pruning. When everything appeared to work, I gradually added the usual extensions, recursive null move pruning, and checks in the qsearch. When I was satisfied with this, I implemented a more efficient search driver. It has now reached the stage where it works rather well, except that my program is so slow (it has a heavy and time-consuming eval) that I need to implement some kind of forward pruning. The techniques I use with aspiration search do not combine very well with MTD(f), because they use alpha and beta. I have to look for something better. Tord
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