Author: Andrew Williams
Date: 13:42:26 08/09/00
Go up one level in this thread
On August 09, 2000 at 16:01:49, Christophe Theron wrote: >On August 09, 2000 at 05:41:22, Andrew Williams wrote: > >>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 > > >Thanks for the idea. > > > Christophe I'd like to claim credit for it, but I got it from a post Don Dailey made here ages ago. Andrew
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