Author: Günther Simon
Date: 09:03:58 10/22/05
Go up one level in this thread
On October 22, 2005 at 11:35:31, Dieter Buerssner wrote: >On October 22, 2005 at 11:05:21, Günther Simon wrote: > >>On October 22, 2005 at 09:34:42, Uri Blass wrote: >> >>>On October 22, 2005 at 08:08:47, Günther Simon wrote: >>> >>>>This position really happened in one of my RWBC games today >>>>and it revealed a bug in a program. 6 men say it is a win. >>>>(Shredder Oracle : M27 with best play) >>>>I am not sure though, if there are programs, which are able >>>>to win this without tablebases at all? (in reasonable time ;) >>>> >>>>Guenther >>>> >>>>[D]4r3/8/8/8/8/6bk/7p/3R3K b - - 0 76 >>> >>>I doubt if there are programs that can find it without tablebases at reasonable >>>time because I expect KRB vs KR to be prune based on no threat but >>>Yace with 5 piece tablebases agree with shredder Oracle >>> >>>New game, 4320'/1 >>>4r3/8/8/8/8/6bk/7p/3R3K b - - 0 1 >>> >>>Analysis by Yace 0.99.87: >>> >>... >> >>>1...Bf4 2.Rf1 Kg4 3.Rb1 Rc8 4.Rf1 Be3 5.Kxh2 Rd8 6.Kg2 Rd2+ 7.Kh1 Bf2 8.Kg2 Bg3+ >>>9.Kg1 Re2 10.Rd1 Bf4 11.Rd3 Be3+ 12.Kf1 Kf3 13.Rd7 Rh2 14.Rf7+ Bf4 15.Rg7 Rc2 >>>16.Re7 Rb2 17.Re8 >>> -+ (-#27) Depth: 22/51 00:29:39 2527052kN >>> >>>(, 22.10.2005) >>> >>>Uri >> >>Thanks for the cpu time Uri. I have one question though, did you >>analyse this with 5 men + Yaces' bitbases or without bitbases? >>(Those would probably speed it up a 'bit') > > >Günther, I didn't try but I doubt that bitbases can help much here. Yace does >not use KRBKR bitbase. 4-men bitbases cannot help at all, to see a huge score >here - they can only help to prune some branches faster. Also note that the >engine was not slowed down very much by TB-accesses. Yace found a significant >score rather fast: > >[from Uri's post] >1...Bf4 2.Rf1 > -+ (-13.23) Depth: 22/44 00:00:49 41473kN > >[over 800 knodes/s] > >Only showing a mate score needed very long. I guess, this is not easy to avoid, >neither is it important for a game. Bitbases will typically not help, to show a >mate score. Even when Yace had KRBKR bitbase, a winning position might be scored >+15 (could show +100 or mate in 500 or something, but that is another thing). >This would not be enough to show the real mate. It could help to find a really >significant score faster. > >Regards, >Dieter Hi Dieter, thanks for the extra infos. I think we have to agree though, what a significant score means here? I mean every engine will show here a huge plus, but nevertheless it will not be capable of winning the game without tablebases, or may be even not with tablebases below 6 men? What score could be called as likely to win the game, when really _playing_ this position? Will > +10 be sufficient for most cases? Example with Amateur 2.86 @WB 4.27x, 128MB hash: (had only my P3 650 cpu available) + 7.62, but quite stuck with the score and PV until d 26 16223 >first : setboard 4r3/8/8/8/8/6bk/7p/3R3K b - - 0 1 18927 >first : time 720000 otim 720000 18927 >first : go 20279 <first : 6 762 1 1497 Re2 Rc1 Rd2 Re1 Bf4 20299 <first : 7 763 3 3902 Re2 Rc1 Rd2 Re1 Rd3 Rf1 Rd2 20329 <first : 8 763 6 7231 Re2 Rc1 Rd2 Re1 Kg4 Rf1 Kh3 20429 <first : 9 761 17 21752 Re2 Rc1 Rd2 Rf1 Rc2 Re1 Rf2 20529 <first : 10 762 27 35102 Re2 Rc1 Rd2 Rf1 Bf2 20709 <first : 11 762 44 56377 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 20980 <first : 12 762 71 96680 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 21340 <first : 13 762 107 154460 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 21911 <first : 14 762 164 245651 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 22492 <first : 15 762 222 335421 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 23153 <first : 16 762 287 444767 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 24295 <first : 17 762 402 630626 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 25877 <first : 18 762 561 904945 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 28370 <first : 19 762 810 1323623 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 31996 <first : 20 762 1173 1956109 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 37614 <first : 21 762 1735 2953422 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 46787 <first : 22 762 2652 4628658 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 63952 <first : 23 762 4369 7291751 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 82138 <first : 24 762 6188 10221718 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 116758 <first : 25 762 9649 16349063 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 199997 <first : 26 762 17972 29900001 Re2 Rc1 Rd2 Rf1 Rc2 Rd1 Rg2 Regards, Guenther
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