Author: Robert Hyatt
Date: 08:06:48 08/10/00
Go up one level in this thread
On August 09, 2000 at 16:42:26, Andrew Williams wrote: >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 I think that solves the 'lazy evaluation' problem. But I am not sure it is a cure-all for pruning based on alpha and beta...
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.