Author: Dieter Buerssner
Date: 13:38:04 07/16/03
Go up one level in this thread
On July 16, 2003 at 14:11:23, Uri Blass wrote:
>On July 16, 2003 at 08:16:29, Grzegorz Sidorowicz wrote:
>>I think this problem is difficult for chess programs using null moves,
>>but if Ruffian can find it in short time I think it is problem not for
>>all.
>>;-)
>
>I think that you are wrong.
>Bg2 has a threat to capture the bishop and some moves after it also has a threat
>to promote a queen.
>
>Maybe there seem to be no threat in the last plies but without null move pruning
>you also lose plies.
For Yace, it makes a difference. In another post, I showed the result for
default parameter (solution found at depth 19, with rather convincing score).
Default for Yace is to use R=2 normaly, and use R=1 in endgames with minor
pieces. If I use R=3 (with much material) and R=2 in the late endgames, I get:
130214357 2:22.9 -0.23 18. 1.a7 e4 2.dxe4 Bxe4+ 3.Bd3 Bc6 4.Kd2 Ka5 5.Bc4
Kb6 6.Bxe6 Bb5
155847517 2:50.8 -0.24 19t 1.a7 e4 2.dxe4 Bxe4+ 3.Bd3 Bc6 4.Ba6 Ka5 5.Bc8
Kb6 6.Bxe6 Kxa7 7.Kd3 Kb6 {0}
207707675 3:50.9 -0.24 19. 1.a7 e4 2.dxe4 Bxe4+ 3.Bd3 Bc6 4.Ba6 Ka5 5.Bc8
Kb6 6.Bxe6 Kxa7 7.Kd3 Kb6 {0}
254666465 4:45.3 -0.33 20t 1.a7 e4 2.dxe4 Bxe4+ 3.Bd3 Bc6 4.Ba6 Ka5 5.Bc8
Kb6 6.Bxe6 Kxa7 7.Kd3 Kb6 8.Kc4 Bg2 9.Bd5 Bf1+
10.Kc3 Be2H 11.Be6H Kc6H 12.Bf5H Kd5H 13.b4H {0}
366425670 7:02.0 -0.33 20. 1.a7 e4 2.dxe4 Bxe4+ 3.Bd3 Bc6 4.Ba6 Ka5 5.Bc8
Kb6 6.Bxe6 Kxa7 7.Kd3 Kb6 8.Kc4 Bg2 9.Bd5 Bf1+
10.Kc3 Be2 11.Be6 Kc6 12.Bf5 Kd5 13.b4 {0}
447359155 8:40.7 -0.31 21t 1.a7 e4 2.dxe4 Bxe4+ 3.Bd3 Bc6 4.Ba6 Ka5 5.Bc8
Kb6 6.Bxe6 Kxa7 7.Kd3 Kb6 8.Kc4 Bg2 9.Bd5 Bf1+
10.Kc3 Be2 11.Be6 Kc6 12.Bf5 {0}
625433582 12:25.1 -0.30 21t+ 1.Bg2 Bxg2 2.e4 f5 3.gxf5 exf5 4.a7 fxe4 5.d4H
e3H 6.dxe5H Be4+H 7.Kd1H Bf3+H 8.Ke1H c4H 9.e6H
Kc5H 10.e7H c3H 11.a8=QH {HT} {571}
676203394 13:24.1 0.07 21++ 1.Bg2 Bxg2 2.e4 f5 3.gxf5 exf5 4.a7 fxe4 5.d4
exd4 6.a8=Q c4
721052360 14:16.8 1.07 21++ 1.Bg2 Bxg2 2.e4 f5 3.gxf5 exf5 4.a7 fxe4 5.d4
exd4 6.a8=Q Kc4
834197876 16:28.8 3.26 21t 1.Bg2 Bxg2 2.e4 f5 3.gxf5 exf5 4.a7 fxe4 5.d4
e3 6.dxe5 Kc4 7.e6 Be4+ 8.Kd1 Kd3 9.e7 Bc6
10.e8=Q Bxe8 11.a8=Q {HT} {491}
So, solution only at depth 21, but still faster than the default parameters! I
did not try other null move parameter, but I would guess, that an order of
magnitude difference in solution time would not be unlikely at all.
Regards,
Dieter
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