Author: scott farrell
Date: 01:44:28 11/12/03
Go up one level in this thread
On November 11, 2003 at 14:22:53, Robert Hyatt wrote: >On November 11, 2003 at 13:31:21, Peter Kappler wrote: > >>On November 11, 2003 at 11:25:59, Robert Hyatt wrote: >> >>>On November 11, 2003 at 11:09:40, José Carlos wrote: >>> >>>>On November 11, 2003 at 10:52:20, Robert Hyatt wrote: >>>> >>>>>On November 11, 2003 at 10:42:10, José Carlos wrote: >>>>> >>>>>> So far, when I cutoff due to null move, I do BetaCutoffs++ but not >>>>>>BetaCutoffsAtFirst++ so my 100 * BCAF / BC statistic gets lowered. Is there an >>>>>>standard for this for I can compare with other people numbers? Should I count a >>>>>>null move cutoff as a beta cutoff at first? Should I not do BetaCutoffs++? >>>>>> >>>>>> José C. >>>>> >>>>>Don't do anything in that case. You only care about the ratio of >>>>>[cutoffs on first move] : [cutoffs on any but first move]. >>>>> >>>>>The higher that ratio the better. >>>> >>>> So you mean not to count null move cutoffs as cutoffs at all, right? >>>> >>>> José C. >>> >>> >>>Right. or you might count null-move searches done, and null-move searches >>>that failed high, if you want to know how effective null-move search is. But >>>it is clearly independent of the idea of base move ordering where the first move >>>should cause a cutoff if one is going to happen. >> >>This first-move-beta-cutoff metric is something that has always bothered me. In >>previous discussions, people have reported an average of ~90%. For my program, >>it's more like 80%, and I'd like to understand why. I don't use a SEE to >>eliminate bad captures, and also don't use internal iterative deepening. >>Perhaps that's enough to explain the difference? > >Very possibly. SEE makes sure you look at the "right" capture first each >time a capture is the best move. Without SEE, you might have to try a couple >before you find the good one. Breaking your fail-high-on-first-move count. > >> >>If either of you have time to run a quick test with one or both of these >>features disabled in your program, I'd be interested to hear how it affects the >>FMBC %. I dont have SEE, but have a function isWeaklyDefended .. which guesses .. it helps some. IID mainly helps when a new move becomes bests, and gets searched deeper than normal. Normal iterative deepening does pretty well if the best stays best. I get an average of better than 90%. It takes tuning. Work on killers and history pays off. Make sure you search bad captures before other moves also. Taking capture out of killers gave me a boost also. Move ordering is all about tuning and fiddling. Scott >> >>-Peter
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.