Author: Robert Hyatt
Date: 08:05:24 11/24/02
Go up one level in this thread
On November 24, 2002 at 07:01:46, Omid David Tabibi wrote: >On November 23, 2002 at 23:33:39, Tony Werten wrote: > >>On November 23, 2002 at 23:14:52, Omid David Tabibi wrote: >> >>>On November 23, 2002 at 22:25:02, Tony Werten wrote: >>> >>>>On November 23, 2002 at 22:14:27, Omid David Tabibi wrote: >>>> >>>>>On November 23, 2002 at 21:50:01, Tony Werten wrote: >>>>> >>>>>>On November 23, 2002 at 21:24:08, Omid David Tabibi wrote: >>>>>> >>>>>>>On November 23, 2002 at 21:09:36, Tony Werten wrote: >>>>>>> >>>>>>>>On November 23, 2002 at 20:52:01, Omid David Tabibi wrote: >>>>>>>> >>>>>>>>>On November 23, 2002 at 20:00:15, Tony Werten wrote: >>>>>>>>> >>>>>>>>>>On November 23, 2002 at 11:11:16, Christophe Theron wrote: >>>>>>>>>> >>>>>>>>>>>On November 23, 2002 at 09:22:37, jefkaan wrote: >>>>>>>>>>> >>>>>>>>>>>>oops, wasn't finished yet.. >>>>>>>>>>>> >>>>>>>>>>>>>are done by using the results of the positional eval >>>>>>>>>>>>>to prune the q-search, >>>>>>>>>>>>and there using only material eval >>>>>>>>>>>> (haven't tried it out yet, and wouldn't >>>>>>>>>>>>know how to do it, but it's only an idea, >>>>>>>>>>>>you know.. to explore options of >>>>>>>>>>>>more effective branch factor reducements >>>>>>>>>>>>and efficient programming (besides >>>>>>>>>>>>lousy solutions as inline assembler >>>>>>>>>>>>and bitboards.. >>>>>>>>>>>>:) >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>>Yes Chess Tiger does much more pruning than known (published) techniques. >>>>>>>>>>> >>>>>>>>>>>I think other top programs do it also. >>>>>>>>>>> >>>>>>>>>>>I still fail to see why the efficiency of an algorithm depends on what your >>>>>>>>>>>QSearch does. >>>>>>>>>>> >>>>>>>>>>>If your pruning algorithm is good, it will increase the strength of the program >>>>>>>>>>>regardless on how good your QSearch is. >>>>>>>>>>> >>>>>>>>>>>If your QSearch is smart, then it will increase the strength even more. >>>>>>>>>>> >>>>>>>>>>>I don't like the idea that some algorithms that have almost nothing to do with >>>>>>>>>>>each other would have such an influence on each other. It is indeed possible and >>>>>>>>>>>it probably happens all the time, but it's hard to work with such hypothesis in >>>>>>>>>>>mind. >>>>>>>>>>> >>>>>>>>>>>I think it's better to first assume that the kind of QSearch you do will not >>>>>>>>>>>interfere with the quality of the pruning algorithm used before the QSearch. >>>>>>>>>>> >>>>>>>>>>>If your QSearch sucks, it's not because you are doing a lot of pruning in the >>>>>>>>>>>"full width" part of the search. It's because it sucks. >>>>>>>>>> >>>>>>>>>>The paper does prove that the more your (q)search sucks, the better your pruning >>>>>>>>>>algoritm seems. But that's not really news. >>>>>>>>>> >>>>>>>>> >>>>>>>>>Does it prove that?! No, it's just my impression based on the data gathered so >>>>>>>>>far. Maybe a reduction of 2 (instead of 1) in case of fail-high report, will >>>>>>>>>work better in programs with heavy extensions and quiescence. >>>>>>>> >>>>>>>>A reduction of 20% seems to be working best in XiniX ( heavy qsearch). >>>>>>> >>>>>>>What do you mean by 20%? (you used a reduction of 1 or 2 in case of fail-high >>>>>>>report?) >>>>>> >>>>>>In case of a fail high I reduce the depth with 20%. ( doesn't work in your silly >>>>>>program :) >>>>>> >>>>> >>>>>Anyway, no matter what the reduction is, you are using verified null-move >>>>>pruning, which is good :-) In my paper I just gave a new null-move pruning >>>>>framework; feel free to play with the values that best fit your program. >>>> >>>>It's a no brainer to implement. If it's not bad then it's worth investigating. >>>> >>>>> >>>>>Even better values do exist. I've been working on them for some time and will >>>>>publish them in near future. >>>> >>>>If I might give an advice. For first reviews, send them it to some active >>>>chessprogrammers, and not to academic has beens. It will save you a lot of >>>>typework. ( you have been quite active on this forum lately ) >>>> >>> >>>I will. However, after posting a new method, several days of "heavy presence" >>>will always be needed to clear things up and answer the questions... >> >>Yes, that's good. >> >>I just think that sending your algoritm to Robert (I think we were using this in >>74 ), Gian Carlo ( Can't work, just implemented it in 3 seconds ) and me ( >>didn't crash my program, must be a good idea ) would have given you some "real" >>input. >> > >Yes, I agree. At least I would have changed my too optimistic comment "it can be >implemented by merely adding a few lines of code"! It is a few lines of >pseudo-code, but practically needs some more tuning to find the best reduction >values... > > It wasn't really "too optimistic". But it is probably easier for me than most, as I am already using internal iterative deepening, which means I can call search recursively for the same position/ply, without wrecking things. That simplifies the code in that I don't do the little block of verification code plus a goto that you used, I simply recursively call search when the null-move search fails high and the "ok-to-verify" flag is set. However, to be efficient, I wanted to modify my "do_null" flag I pass to each successive search() call, so that it would include "do_null & verify" to avoid adding a new search parameter. That was a bit messier than I originally thought and that is the only thing that caused my initial attempt to produce errors, in that I simply blew the two flags out at times and did extra verification searches when I shouldn't have due to the bug. BTW, when I get this working, I have a huge cluster of quad xeons. I can certainly re-run all your test positions with Crafty, and let 'em run 32 at a time to depth 12, 13, and 14 to see what happens... If you want to send me your positions, I should probably re-run the 9, 10 and 11 tests as well to get a baseline comparison between crafty and your program also... but I have plenty of machine time to run deeper tests... >>Tony >> >>> >>> >>>>BTW last time we mailed I concluded your last name was David, were does the >>>>Tabibi come from ? >>>> >>> >>>My full name has always been Omid David Tabibi. But I usually use just David as >>>my last name in informal occasions. After ICGA put my name as "O.D. Tabibi" on >>>their cover, I thought it would be a good idea to use my full name here to avoid >>>confusion. >>> >>> >>>>Tony >>>> >>>>> >>>>> >>>>>>In XiniX I have partial extensions (PLY is 32). >>>>>>The addition to your idea is to give big reductions when there is still a lot of >>>>>>searchdepth remaining. So fe when there is 12 ply left I give more reduction >>>>>>than when there's 6 ply left (with a minimum of 1 ply ) That's 6*0,2 is 1,2 ply >>>>>>more. For XiniX that seems to make the difference between a good and a bad new >>>>>>idea. >>>>>> >>>>>>Tony >>>>>> >>>>>>> >>>>>>> >>>>>>>>I'm >>>>>>>>interessed in your idea. It's commented out in my program now, but not deleted. >>>>>>>>I still have to play with it some more. >>>>>>>> >>>>>>>>Despite of the negative comments you had, I don't think it's a bad idea. I'm >>>>>>>>just not convinced yet it's a good one. >>>>>>>> >>>>>>> >>>>>>>It took me several months of experiments to get convinced. After a little more >>>>>>>tuning and playing with different reduction values (1 or 2), I believe you will >>>>>>>be convinced too ;-) >>>>>>> >>>>>>> >>>>>>>>Tony >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>>>Tony >>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Christophe
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