orgfert wrote:Rebel wrote:I assume there is rational explanation for this ...
The following just might fall within the scant capabilities of Rybka embusques. Determine if any engines beside Fruit and its un-cromulent offspring find themselves at sea in this position.
http://www.talkchess.com/forum/viewtopi ... 233#427233
It is however, only one position. I found that the last
100 versions of Rainbow Serpent actually could not solve this anymore, all of them showing 0.00 scores, and the ones before build 224 could. It had nothing to do with Transposition Tables in this case, but fawlty Step 14C "Double Pass Stand Pat Futility Pruning"
I can assure you that the affected code is not present in Fruit either/or Rybka, unless someone copied it from the free search.cpp that is out there somewhere, but seeing it is buggy as #$@ I hope that no one has. Anyway thanks very much to Harm-Geert working on Sparctacus endgame theory for the Open NK next weekend, or I would probably never have found this out, I never test any of those changes by actually playing testgames, so from time to time the engine has to undergo serious regression therapy. In this case of about 100 versions.
Eelco
With "Double Pass Stand Pat Futility Pruning" commented out it works again:
8/6k1/1p6/6P1/p1p5/P1P2K1p/2P2P2/8 b - -
Engine: eXperimental Tommy Cooper - Rainbow Serpent Build 324 (Athlon 2009 MHz, 48 MB) by Tord Romstad, Marco Costalba, Joona Kiiski
1/01 0:00 +1.05 1...Kg6 (12) 0
2/02 0:00 +0.44 1...Kg6 2.Kg3 (156) 3
3/04 0:00 +0.20 1...Kg6 2.Kg3 Kxg5 3.Kxh3 (1.108) 24
4/04 0:00 +0.20 1...Kg6 2.Kg3 Kxg5 3.Kxh3 (2.869) 62
5/06 0:00 0.00 1...Kg6 2.Kg3 Kxg5 3.Kxh3 b5 4.Kg3 (5.111) 82
6/15 0:00 +0.12 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.f3 Ke5 6.Kg3 Kf5 7.Kf2 Kf4 8.Ke2 Ke5 (9.216) 148
7/14 0:00 +0.08 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kg4 6.Ke2 Kf4 7.f3 Ke5 8.Ke3 (17.986) 230
8/14 0:00 -0.10-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kg4 6.Ke2 Kf4 7.f3 Ke5 8.Ke3 (29.824) 320
8/12 0:00 -0.15 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kg4 6.Ke2 Kf5 7.Ke3 (36.988) 339
9/14 0:00 -0.16 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kg4 6.Ke2 Kf5 7.Ke3 Ke5 8.f3 (47.629) 436
10/18 0:00 -0.04 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kf4 6.Kf2 b5 7.Ke2 Kf5 8.Ke3 Ke5
9.f4+ Kf5 10.Kf3 (66.230) 473
11/18 0:00 -0.24-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kf4 6.Kf2 b5 7.Ke2 Kf5 8.Ke3 Ke5
9.f4+ Kf5 10.Kf3 (107.984) 531
11/14 0:00 -0.28 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kg3 Kf5 7.f4 Ke4 8.Kg4 (140.175) 599
12/18 0:00 -0.60-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kg3 b5 7.f4+ Kf6 8.Kf3 Kf5
9.Ke3 Ke6 10.Ke4 (222.500) 678
12/16 0:00 -0.52 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kg3 b5 7.f4+ Kf6 8.Kg4 Ke7
9.Kg5 (247.003) 688
13/24 0:00 -0.56 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kd5
9.Ke3 Kc5 10.Ke4 Kd6 11.f4 Ke6
12.f5+ Kf6 13.Kf4 (265.005) 706
14/20 0:00 -0.64 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke5 8.Ke3 Kd5
9.f4 Ke6 10.Ke4 Kf6 11.f5 (334.294) 714
15/22 0:00 -0.60 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Kf5 8.Ke3 Kf6
9.Ke4 Kf7 10.f3 Kf6 11.f4 Ke7 12.Ke5 (391.496) 737
16/26 0:00 -0.64 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kf4
9.Kf2 Kf5 10.Ke3 Ke5 11.f4+ Kf5
12.Kf3 Ke6 13.Ke4 Kf6 14.f5 (468.667) 749
17/26 0:00 -0.66 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kf5
9.Ke3 Ke5 10.f4+ Kf5 11.Kf3 Kf6
12.Kg4 Kg6 13.f5+ Kf6 14.Kf4 (528.074) 751
18/28 0:00 -0.78-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kf5
9.Ke3 Ke5 10.f4+ Kf5 11.Kf3 Kf6
12.Kg4 Kg6 13.Kf3 Kf5 14.Kg3 Kf6 (727.935) 763
18/24 0:01 -0.80 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kf5 6.Kg3 Kg5 7.f4+ Kf5 8.Kf3 b5
9.Kg3 Ke6 10.Kg4 Kf6 11.f5 Ke7
12.Kf4 Kf8 13.f6 (802.600) 778
19/22 0:01 -0.80 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Kf5 8.Ke3 Kf6
9.Ke4 Ke7 10.f4 Kd6 11.Kd4 Ke6
12.Kc5 (1.093.983) 804
20/24 0:02 -0.92-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Kf5 8.Ke3 Ke5
9.f4+ Kd5 10.Kf3 Ke6 11.Ke4 Kd6
12.Kd4 Ke6 13.Kc5 (1.674.651) 800
20/36 0:02 -0.98 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kh2 Kf3
5.Kg1 Kf4 6.Kg2 b5 7.Kf1 Kf3 8.Ke1 Kf4
9.Ke2 Kf5 10.Kf3 Ke5 11.Ke3 Kf5
12.f3 Ke5 13.f4+ Kd5 14.Kf3 Kc6 (2.136.433) 818
21/36 0:03 -1.22-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kf4
9.Kf2 Kf5 10.Ke3 Ke5 11.f4+ Kd5
12.Kf3 Kc6 13.f5 Kd5 14.Kg4 Kd6 (2.901.107) 818
21/28 0:04 -1.54-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kf4
9.Kf2 Kf5 10.Ke3 Ke5 11.f4+ Kd6
12.Ke4 Ke6 13.Kd4 Kf7 14.Kc5 Ke6 (3.940.980) 829
21/32 0:05 -1.22++ 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Ke4 7.Ke2 Kf4 8.f3 Ke5
9.Ke3 Kd5 10.f4 Kc5 11.Ke4 Kd6
12.Kf5 Ke7 13.Kg6 Kd7 14.f5 Ke7 (4.380.177) 834
21/28 0:06 -2.08-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Ke4 7.Ke2 Kf4 8.f3 Ke5
9.Ke3 Kd5 10.f4 Kc5 11.Ke4 Kd6
12.Kf5 Ke7 13.Kg6 Kd7 14.f5 Kd6 (5.485.303) 839
21/28 0:06 -2.43++ 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Ke4 7.Ke2 Kf4 8.f3 Ke5
9.Ke3 Kd5 10.f4 Kc5 11.Ke4 Kd6
12.Kf5 Ke7 13.Kg6 Kd7 14.f5 Kd6 (5.501.490) 840
21/34 0:06 -1.93++ 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kf1 Kf3 6.Ke1 Kf4 7.Ke2 Ke4 8.f3+ Kd5
9.Ke3 Kc6 10.Kd4 Kb6 11.f4 Kc6
12.Ke4 Kd6 13.Kf5 Ke7 14.Kg6 Kd8 (5.526.104) 840
21/32 0:06 -1.97 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kf4 7.Ke2 Kf5 8.Ke3 Ke5
9.f4+ Kd5 10.Kf3 b5 11.Ke3 Kc5
12.Ke4 Kd6 13.Kd4 Kc6 14.Ke5 Kd7 (5.656.571) 842
22/26 0:08 -3.06-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kf4 7.Ke2 b5 8.Kf2 Kg5
9.Ke3 Kf5 10.Kd4 Kf4 11.Kc5 Kxf3
12.Kxb5 Ke4 13.Kxc4 Kf5 14.Kb4 (7.116.284) 852
22/34 0:09 -4.95 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kf4 7.Ke2 Ke5 8.Ke3 Kf5
9.f4 Kf6 10.Ke4 b5 11.f5 Kf7 12.Kf4 Kf6
13.Kg4 Kf7 14.Kg5 Kg7 (8.083.633) 859
23/36 0:10 -4.95 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kf4 7.Ke2 Ke5 8.Ke3 Kf5
9.f4 Ke6 10.Ke4 Kf6 11.f5 Ke7 12.Ke5 Kf7
13.f6 Kg8 14.Ke6 Kf8 (8.679.591) 858
24/25 0:11 -5.11 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kh5 7.Kg3 Kh6 8.Kg4 Kg7
9.Kg5 Kh8 10.Kf5 Kg8 11.f4 Kf7
12.Ke5 Ke7 13.Kf5 Kf7 (9.627.431) 860
25/40 0:13 -6.02 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf1 Kf5 7.Ke2 Kf4 8.Kf2 b5
9.Ke2 Ke5 10.Ke1 Kf5 11.Kf1 Kg6
12.Ke2 Kf7 13.Ke3 Kg8 14.Kf4 b4 (11.838.602) 862
26/31 0:20 -7.03-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kg6 7.Ke3 b5 8.Ke2 Kg7
9.Ke3 Kf7 10.Ke4 Kf8 11.Kf4 b4
12.cxb4 c3 13.Ke4 Ke7 14.f4 Kd8 (18.222.635) 885
26/36 0:45 -9.76-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kg5 6.Kf2 Kg6 7.Ke3 b5 8.f4 Kf5
9.Kf3 Kg6 10.Ke4 Kh6 11.f5 Kg7
12.Kf3 Kf8 13.Ke3 Ke7 14.Kf4 Kf7 (42.923.403) 945
26/13 0:49 -9.77++ 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kf4 6.Kf2 b5 7.Ke2 Kf5 (46.483.792) 930
26/22 1:27 -15.93 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf5 4.Kg3 Ke4
5.f4 Ke3 6.f5 Ke2 7.f6 Kd2 8.Kg4 Kxc3
9.f7 Kd4 10.f8Q Ke5 11.Kf3 c3 12.Ke3 (76.167.593) 866
27/17 3:59 -26.34 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Kg4
5.f3+ Kf4 6.Kf2 b5 7.Ke2 Kg3 8.Ke3 Kg2
9.f4 Kf1 (190.316.853) 796
28/04 9:47 -37.90 1...Kg6 2.Kg3 Kxg5 3.Kxh3 (481.935.961) 820
29/09 21:03 -57.01 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kg1 Kg4 (1.110.408.233) 878
30/31 27:00 -84.50 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Ke5
5.Kg3 Kf6 6.Kf4 Ke6 7.Kg5 Kd5 8.f4 b5
9.f5 Kd6 10.f6 b4 11.cxb4 Ke6 12.b5 Kd5
13.f7 Kd4 14.f8Q Kc3 (1.383.843.179) 854
31/31 27:16 -84.50 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Ke5
5.Kg3 Kf6 6.Kf4 Ke6 7.Kg5 Kd5 8.f4 b5
9.f5 Kd6 10.f6 b4 11.cxb4 Ke6 12.b5 Kd5
13.f7 Kd4 14.f8Q Kc3 (1.394.241.513) 852
32/31 27:21 -84.50 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Ke5
5.Kg3 Kf6 6.Kf4 Ke6 7.Kg5 Kd5 8.f4 b5
9.f5 Kd6 10.f6 b4 11.cxb4 Ke6 12.b5 Kd5
13.f7 Kd4 14.f8Q Kc3 (1.398.040.938) 851
33/31 27:29 -84.50 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 Ke5
5.Kg3 Kf6 6.Kf4 Ke6 7.Kg5 Kd5 8.f4 b5
9.f5 Kd6 10.f6 b4 11.cxb4 Ke6 12.b5 Kd5
13.f7 Kd4 14.f8Q Kc3 (1.404.005.032) 851
34/09 28:05 -84.52 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.f3 Ke3 (1.427.940.617) 847
35/24 30:38 -84.52-- 1...Kg6 2.Kg3 Kxg5 3.Kxh3 Kf4 4.Kg2 b5
5.Kg1 Kf3 6.Kf1 b4 7.cxb4 Kf4 8.b5 c3
9.Kg2 Ke5 10.Kg3 Ke6 11.f4 Kf5 12.b6 Ke4
13.b7 (1.558.279.989) 847
best move: Kg7-g6 time: 57:55.390 min n/s: 950.328 nodes: 3.302.760.850