Test Position

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bob
Posts: 20549
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Location: Birmingham, AL

Re: Test Position

Post by bob » Thu Sep 10, 2009 9:05 pm

Tord Romstad wrote:
bob wrote: This might be a case of some aggressive check extension working, where I have found in real games that the give-check extension is good, the rest are either harmful or do not help.
I don't think so. Crafty extends checks far more aggressively than Stockfish, unless you have changed something recently. Stockfish extends checks by only half a ply, except at PV nodes.
I only extend checks, and by 1 ply everywhere. But i have no other extensions of any kind. No one-legal-move extensions, no passed pawn push extensions, etc... I thought you did some of those still???

Also note that the discussion is not only about stockfish. Some others find it very quickly, some strong programs take a long time to find the move. It has my attention because crafty quickly sees that if I play f5, it is losing with white, with a worse score than if I play Be8. But given the choice, it likes Be8 for a long time. I do not know when or if it will switch to f5. I am running it, but I am only using one CPU so that I can get repeatable results if I find something to test or debug...

Spock

Re: Test Position

Post by Spock » Thu Sep 10, 2009 9:10 pm

Naum 4 finds it very quickly on my quad, about 5 mins

15/35 0:01 -0.93 1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Kg2 Bxe5 6.Bc2 Bb5 7.Bd3 Bxd3 8.Qxd3 Bd4 (3.314.464) 3115
16/39 0:02 -0.87 1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Ne3 Bxe5 5.Qxh4 Bc6 6.Qb4+ Kg8 7.Qg4 Qb1 8.Qb4 Bf3 9.Qd2 (8.291.619) 3380
17/59 0:06 -0.89 1...Be8 2.Ng4 Qb2+ 3.Kf1 Bd2 4.Qf6 Qc1 5.Qh8+ Ke7 6.Qf6+ Kd7 7.Qf3 Kc7 8.Ne3 Bxe3 9.fxe3 Qa1 (21.945.690) 3568
18/47 0:09 -0.89 1...Be8 2.Ng4 Qb2+ 3.Kf1 Bd2 4.Qf6 Qc1 5.Qh8+ Ke7 6.Qf6+ Kd7 7.Qf3 Kc7 8.Ne3 Bxe3 9.fxe3 Qa1 10.Qg4 (34.095.825) 3572
19/58 0:22 -0.88 1...Be8 2.Ng4 Qb2+ 3.Kf1 Bd2 4.Ne3 Bc6 5.Qf6 Qd4 6.Qh8+ Ke7 7.Qf6+ Ke8 8.Bf3 Bxf3 9.Qxf3 Qxe5 10.Ke2 Bxe3 (81.371.373) 3672
20/50 0:40 -0.88 1...Be8 2.Ng4 Qb2+ 3.Kf1 Bd2 4.Ne3 Bc6 5.Qf6 Qd4 6.Qh8+ Ke7 7.Qf6+ Ke8 8.Bf3 Bxf3 9.Qxf3 Qxe5 10.Ke2 Bxe3 11.Qxe3 (153.296.020) 3787 TB:4
21/62 1:20 -1.02 1...Be8 2.Ng4 Qb2+ 3.Kf1 Bd2 4.Ne3 Bc6 5.Qf6 Qd4 6.Qh8+ Ke7 7.Qf6+ Ke8 8.Bf3 Bxf3 9.Qxf3 Qxe5 10.Qa8+ Ke7 11.Qb7+ Kf8 (308.538.172) 3842 TB:27
21/62 5:02 -4.55 1...f5 2.exf6 e5 3.Qg4 Bb7 4.Nf7 Qa2+ 5.Kf1 Qd2 6.Qe2 Kxf7 7.Qxd2 Bxd2 8.Be2 Bc6 9.Bd3 Bxg5 10.Kg1 Bxf6 11.Be2 Bd7 (1.199.737.567) 3962 TB:881
22/62 6:35 -4.55 1...f5 2.exf6 e5 3.Qg4 Bb7 4.Nf7 Qa2+ 5.Kf1 Qd2 6.Qe2 Kxf7 7.Qxd2 Bxd2 8.Be2 Bc6 9.Bd3 Bxg5 10.Kg1 Bxf6 11.Be2 Bd7 12.Bg4 (1.584.826.257) 4011 TB:1.032
23/62 8:40 -4.55 1...f5 2.exf6 e5 3.Qg4 Bb7 4.Nf7 Qa2+ 5.Kf1 Qd2 6.Qe2 Kxf7 7.Qxd2 Bxd2 8.Be2 Bc6 9.Bd3 Bxg5 10.Kg1 Bxf6 11.Be2 Bd7 12.Bg4 Be8 (2.114.712.732) 4065 TB:1.151
24/62 12:57 -4.55 1...f5 2.exf6 e5 3.Qg4 Bb7 4.Nf7 Qa2+ 5.Kf1 Qd2 6.Qe2 Kxf7 7.Qxd2 Bxd2 8.Be2 Bc6 9.f3 Bxg5 10.Kf2 Bxf6 11.Bd3 Bd7 12.Kg2 Bg5 13.Bc2 (3.211.178.123) 4129 TB:1.855

Tord Romstad
Posts: 1808
Joined: Wed Mar 08, 2006 8:19 pm
Location: Oslo, Norway

Re: Test Position

Post by Tord Romstad » Thu Sep 10, 2009 9:11 pm

bob wrote:
Tord Romstad wrote:
bob wrote: This might be a case of some aggressive check extension working, where I have found in real games that the give-check extension is good, the rest are either harmful or do not help.
I don't think so. Crafty extends checks far more aggressively than Stockfish, unless you have changed something recently. Stockfish extends checks by only half a ply, except at PV nodes.
I only extend checks, and by 1 ply everywhere. But i have no other extensions of any kind. No one-legal-move extensions, no passed pawn push extensions, etc... I thought you did some of those still???
Yes, we do. You talked about "aggressive check extension" in particular, which is why I replied the way I did.

At non-PV nodes, Stockfish extends single replies and captures leading to a pawn endgame by 1 ply, and checks and pawn pushes to the 7th rank by half a ply.

I think zugzwang is the most likely reason why the results of different programs vary so much here, though. The position does look very zugzwang-ish.

bob
Posts: 20549
Joined: Mon Feb 27, 2006 6:30 pm
Location: Birmingham, AL

Re: Test Position

Post by bob » Thu Sep 10, 2009 9:16 pm

Tord Romstad wrote:
bob wrote:
Tord Romstad wrote:
bob wrote: This might be a case of some aggressive check extension working, where I have found in real games that the give-check extension is good, the rest are either harmful or do not help.
I don't think so. Crafty extends checks far more aggressively than Stockfish, unless you have changed something recently. Stockfish extends checks by only half a ply, except at PV nodes.
I only extend checks, and by 1 ply everywhere. But i have no other extensions of any kind. No one-legal-move extensions, no passed pawn push extensions, etc... I thought you did some of those still???
Yes, we do. You talked about "aggressive check extension" in particular, which is why I replied the way I did.

At non-PV nodes, Stockfish extends single replies and captures leading to a pawn endgame by 1 ply, and checks and pawn pushes to the 7th rank by half a ply.

I think zugzwang is the most likely reason why the results of different programs vary so much here, though. The position does look very zugzwang-ish.
I backed off the null-move stuff, all the way to zero for one run, and it doesn't seem to make any difference...

Tord Romstad
Posts: 1808
Joined: Wed Mar 08, 2006 8:19 pm
Location: Oslo, Norway

Re: Test Position

Post by Tord Romstad » Thu Sep 10, 2009 9:58 pm

bob wrote:
Tord Romstad wrote:I think zugzwang is the most likely reason why the results of different programs vary so much here, though. The position does look very zugzwang-ish.
I backed off the null-move stuff, all the way to zero for one run, and it doesn't seem to make any difference...
But this does not prove that zugzwang is not the issue! Disabling null move has another obvious effect besides allowing you to detect zugzwangs: It dramatically reduces your search depth. Assume that one critical line ends up in a zugzwang, while another critical line does not contain a zugzwang, but is very deep. In this case, disabling null move probably isn't going to help you to find the solution.

The right way to test is to run with and without zugzwang detection. I would have tested it myself if I could, but my computer is busy right now.

bob
Posts: 20549
Joined: Mon Feb 27, 2006 6:30 pm
Location: Birmingham, AL

Re: Test Position

Post by bob » Thu Sep 10, 2009 10:05 pm

Tord Romstad wrote:
bob wrote:
Tord Romstad wrote:I think zugzwang is the most likely reason why the results of different programs vary so much here, though. The position does look very zugzwang-ish.
I backed off the null-move stuff, all the way to zero for one run, and it doesn't seem to make any difference...
But this does not prove that zugzwang is not the issue! Disabling null move has another obvious effect besides allowing you to detect zugzwangs: It dramatically reduces your search depth.

Doesn't reduce mine. :) I just let it run longer. :)


Assume that one critical line ends up in a zugzwang, while another critical line does not contain a zugzwang, but is very deep. In this case, disabling null move probably isn't going to help you to find the solution.

The right way to test is to run with and without zugzwang detection. I would have tested it myself if I could, but my computer is busy right now.

kgburcham
Posts: 2016
Joined: Sun Feb 17, 2008 3:19 pm

Rybka & Zappa

Post by kgburcham » Thu Sep 10, 2009 10:08 pm

[D] 5k2/5p2/2b1p1pN/1p2P1P1/5Q1p/1Pb4P/4KP2/1q1B4 b - - 0 1

Rybka 3:

1...Be8 2.Ng4 Qb2+ 3.Kf1[] Bd2 4.Ne3 Bc6 5.Qf6 Bxe3 6.Qd8+ Be8 7.Qd6+ Kg7 8.fxe3 Qh2 9.Bg4 Qh1+ 10.Ke2 Bc6 11.Qb4 Qb1 12.Kf2 Qc2+ 13.Ke1 Qb2
-/+ (-1.22) Depth: 19 00:00:52 14719kN
1...f5
-/+ (-1.26 !) Depth: 19 00:01:21 23560kN
1...f5
-+ (-1.46 !) Depth: 19 00:01:28 26139kN
1...f5
-+ (-1.86 !) Depth: 19 00:01:42 30979kN
1...f5
-+ (-2.66 !) Depth: 19 00:02:08 39613kN
1...f5
-+ (-4.26 !) Depth: 19 00:04:03 80001kN
1...f5 2.Qe3 Qb2+[]
-+ (-4.90) Depth: 19 00:07:31 163mN, tb=33



Zappa Mexico II:

1...Be8 2.Ng4 b4 3.Ne3 Bc6 4.Qxh4 Kg8 5.Qc4 Bb7 6.Kf1 Bf3 7.Qc8+ Kg7 8.Qd7 Bxe5 9.h4
-/+ (-1.03) Depth: 16/51 00:01:05 228mN
1...Be8 2.Ng4 b4 3.Ne3 Bc6 4.Qxh4 Kg8 5.Nc4 Be4 6.Qg3 Qa2+ 7.Kf1 Qa1 8.Ke2 Qb1 9.h4 Bd4 10.Ke1
-/+ (-1.06) Depth: 17/53 00:01:36 330mN
1...f5 2.exf6 e5 3.Qg4 Bb7 4.Nf7 Qa2+ 5.Kf1 Qd2 6.Qe2 Kxf7 7.Qxd2 Bxd2 8.Be2 Bc6 9.Bg4 Bxg5 10.Ke2 e4 11.Kd1 Kxf6
-+ (-3.41) Depth: 17/53 00:04:51 947mN

plattyaj

Re: Test Position

Post by plattyaj » Fri Sep 11, 2009 12:27 am

Obviously Schola is a patzer compared to many of the engines taking a long time but finds it pretty early. It's search does a couple of extensions (check mostly) and has LMR but nothing special there. There's no zungwang detection and it's standard null move applied pretty much everywhere.

One suspicion is that it's one of the cases where a very basic evaluation is actually better than one that considers a lot of factors.

Andy.

Robert Flesher
Posts: 1213
Joined: Tue Aug 18, 2009 1:06 am

Re: Test Position

Post by Robert Flesher » Fri Sep 11, 2009 12:44 am

Rybka 3.0 .... 35 seconds on my hardware.

New game
5k2/5p2/2b1p1pN/1p2P1P1/5Q1p/1Pb4P/4KP2/1q1B4 b - - 0 1

Analysis by Rybka 3 Dynamic :

1...Be8
µ (-1.04) Depth: 2 00:00:00
1...Be8
µ (-0.74) Depth: 3 00:00:00
1...Be8
µ (-0.86) Depth: 4 00:00:00
1...Be8 2.Ng4
µ (-0.87) Depth: 5 00:00:00
1...Be8 2.Ng4 Qa2+
µ (-0.79) Depth: 6 00:00:00 8kN
1...Be8 2.Ng4 Qa2+ 3.Kf1 Qa1
µ (-0.82) Depth: 7 00:00:00 13kN
1...Be8 2.Ng4 Qa2+ 3.Kf1 Qa1 4.Ke2
µ (-0.82) Depth: 8 00:00:00 18kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Qd3
µ (-0.94) Depth: 9 00:00:00 40kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Qd3
µ (-0.94) Depth: 10 00:00:00 55kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Ke2 b4 5.Ne3 Bb5+ 6.Kf3
µ (-1.04) Depth: 11 00:00:00 100kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Ke2 b4 5.Ne3 Bb5+ 6.Kf3 Kg8 7.Kg4 Bd4 8.Qf3
µ (-1.03) Depth: 12 00:00:00 155kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Kg2 Bxe5 6.Be2 Bd4 7.Nf6 Qc1 8.Nxe8 Qxg5+
µ (-1.14) Depth: 13 00:00:01 340kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Kg2 Bxe5 6.Bc2 Bb5 7.Bd3 Bxd3 8.Qxd3 Qa5 9.Kg1 Kg7 10.Nxe5 Qa1+ 11.Kg2 Qxe5
µ (-1.10) Depth: 14 00:00:03 717kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Kg2 Bxe5 6.Bc2 Bb5 7.Bd3 Bxd3 8.Qxd3 Qa5 9.Kg1 Kg7 10.Nxe5 Qa1+ 11.Kg2 Qxe5 12.Kf1 Qb2 13.Qe3 Kg8
µ (-1.09) Depth: 15 00:00:05 1097kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Kg2 Bxe5 6.Bc2 Bb5 7.Bd3 Bxd3 8.Qxd3 Qa5 9.Kg1 Kg7 10.Nxe5 Qa1+ 11.Kg2 Qxe5 12.Kf1 Qb2 13.Qe3 Kg8
µ (-1.09) Depth: 16 00:00:09 1752kN
1...Be8 2.Ng4 Qb2+ 3.Kf1 Qa1 4.Qf3 b4 5.Kg2 Bxe5 6.Bc2 Bb5 7.Ne3 Qd4 8.Bxg6 Qf4
µ (-1.05) Depth: 17 00:00:20 4040kN
1...f5
µ (-1.29) Depth: 17 00:00:35 7201kN
1...f5
-+ (-1.49) Depth: 17 00:00:48 10094kN
1...f5
-+ (-1.89) Depth: 17 00:00:53 11157kN

(, Microsoft 10.09.2009)

peter
Posts: 1782
Joined: Sat Feb 16, 2008 6:38 am
Full name: Peter Martan

Re: Test Position

Post by peter » Fri Sep 11, 2009 5:04 am

5k2/5p2/2b1p1pN/1p2P1P1/5Q1p/1Pb4P/4KP2/1q1B4 b - - 0 1

Analysis by Deep Fritz 10:
...
1...Le8 2.Sg4 Db2+ 3.Kf1 Da1 4.Df3 b4 5.De2 Dc1 6.Dd3 Dxg5 7.Dd6+ Kg7 8.Le2 Dc1+ 9.Kg2 Dc2 10.Lc4 De4+ 11.Kg1 De1+
-/+ (-1.09) Tiefe: 16/39 00:00:03 19275kN
1...f5
-/+ (-1.09) Tiefe: 16/39 00:00:04 22358kN
...
1...f5
-+ (-2.41) Tiefe: 20/47 00:00:30 189mN
1...f5 2.exf6 e5 3.Dg4 Lb7 4.Sg8 Db2+ 5.Kf1 Dd2 6.De2 Kxg8 7.f3 Kf7 8.b4
-+ (-5.38) Tiefe: 20/58 00:01:58 806mN, tb=3
1...f5 2.exf6
-+ (-5.10) Tiefe: 21/44 00:02:16 925mN, tb=3
...
1...f5 2.exf6 e5
-+ (-3.70) Tiefe: 22/46 00:03:14 1303mN, tb=3
Peter.

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