Author: Andrew Williams
Date: 02:41:22 08/09/00
Go up one level in this thread
On August 08, 2000 at 15:56:04, Christophe Theron wrote: >On August 06, 2000 at 16:36:15, Vincent Diepeveen wrote: > >>Show me an MTD program that uses less nodes a ply as DIEP does. >> >>What diep is doing is very simple in search: >> >> PVS (starting with -infinite) >> check extensions >> checks in qsearch >> nullmove R=3 >> no other crap. no pruning. Perhaps at WMCC i prune a bit, >> but that's because against computers playing is different. >> >> Yet i'm missing programs using less nodes a ply with MTD. >> I"m missing *any* deep searching program that uses MTD actually. > > >Anmon, a french chess program, uses MTD(f). It is a strong program. > >If you are not pruning in the tree, then MTD(f) should be better for you. I >don't use MTD(f) because I use the value of alpha and beta to prune in the tree, >and with MTD(f) this kind of pruning makes the search really unstable (you get a >fail-high, and when you re-search with a higher window you get a fail-low, >oops). > > > > Christophe What you can do in these cases is to use the external bounds instead of alpha and beta. By "external bounds" I mean the bounds that have been established in the mtdf() loop which is driving the alphab-beta search. Cheers Andrew
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