Author: Paul
Date: 09:02:16 10/08/01
Go up one level in this thread
On October 08, 2001 at 11:28:49, Uri Blass wrote: >On October 08, 2001 at 10:42:41, Paul wrote: > >>On October 08, 2001 at 09:31:57, Uri Blass wrote: >> >>>On October 08, 2001 at 07:29:04, Bernhard Bauer wrote: >>> >>>>On October 07, 2001 at 21:39:52, Robert Hyatt wrote: >>>> >>>>> >>>>>2. You can tone down (or even disable) the null-move search. You can >>>>>try sel=2/3 (the default) then sel=2/2, sel=1/1, and finally sel=0/0 which >>>>>will turn null-move off. This will further reduce the search depth and overall >>>>>strength. >>>>> >>>> >>>>From my experience sel=0/0 doesn't turn null-move completely off. >>>>Here an example with sel=0/0 >>>> >>>>[D]4B/8/6N/5p/1r4p/6pk/7b/4K2Q w - - >>>> >>>> >>>> (4) 6-> 1.90 -0.44 1. Bc6 Rb1+ 2. Ke2 Rxh1 3. Nf4+ Kh4 >>>> 4. Bxh1 Kg5 5. Ke3 >>>> (3) 7 1.96 -0.22 1. Bc6 Rb1+ 2. Ke2 Rxh1 3. Nf4+ Kh4 >>>> 4. Bxh1 Bg1 5. Bg2 Bd4 >>>> 7 2.75 ++ 1. Kd2!! >>>> (2) 7 3.79 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 >>>> (2) 7-> 6.29 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 >>>> 8 8.14 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 >>>> (2) 8-> 14.57 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 >>>> 9 20.50 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 10. Nf4 >>>> (2) 9-> 42.50 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 10. Nf4 >>>> 10 1:05 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 10. Nf4 Bxf4 >>>> (2) 10-> 2:22 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 10. Nf4 Bxf4 >>>> 11 3:35 0.00 1. Kd2 g2 2. Qe1 g1=Q 3. Qh4+ Kg2 4. >>>> Bc6+ Re4 5. Bxe4+ fxe4 6. Qxg4+ Kh1 >>>> 7. Qxe4+ Qg2+ 8. Ke3 Qxe4+ 9. Kxe4 >>>> Bg3 10. Nf4 Bxf4 11. Kxf4 Kh2 >>>> time=5:00 cpu=201% mat=4 n=142525014 fh=89% nps=474k >>>> ext-> chk=10823921 cap=287226 pp=207595 1rep=668532 mate=112510 >>>> predicted=0 nodes=142525014 evals=28834988 >>>> endgame tablebase-> probes done=0 successful=0 >>>> hashing-> trans/ref=47% pawn=99% used=99% >>>> SMP-> split=1018 stop=90 data=7/32 cpu=10:05 elap=5:00 >>>> >>>> >>>>Kind regards >>>>Bernhard >>> >>>I am not sure if the problem here is null move pruning. >>> >>>The problem may be that programs need to know that there is a chance to win in >>>KN vs something(otherwise they may evaluate it as not more than a draw and stop >>>to search) >>> >>>There are programs without this knowledge so they cannot see that >>>1.Bc6 Rb1+ 2.Ke2 Rxh1 3.Bg2+ is leading to a forced mate. >>> >>>Deep Fritz with the default parameters(null move pruning) has no problem to find >>>the win because it has this knowledge that king and knight can mate. >>> >>>Uri >> >>Hi, >> >>I'm sure Bernhard is right here, checked with my own program (no endgame >>knowledge) and the only thing that helps here is turning of recursive nullmove. >>Just one nullmove per branch is still ok, but with recursive nullmove mine >>doesn't get a winning score. > >You are right that the reason for Crafty is null move pruning but there are also >other reasons to fail to find the right move(Junior cannot see that white wins >because of the fact that it believes that knight cannot win). Yes Uri, you're right about that, have seen you write that about Junior before. A case of "almost correct" endgame knowledge to speed up the search, but that works counterproductive here. Paul >>I think that Deep Fritz has a smarter kind of nullmove than older versions of >>Fritz (double nullmove or whatever). >Yes > >I know that there are cases when Deep Fritz fails to find moves because of null >move pruning but not in this case. > >I guess that there are positions when it turns off null move pruning(it may be >logical to do it in some simple positions when the number of moves of the >opponent is small). > >Uri
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