Author: Uri Blass
Date: 06:31:57 10/08/01
Go up one level in this thread
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
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