Author: Dieter Buerssner
Date: 15:53:34 05/14/01
Go up one level in this thread
On May 14, 2001 at 12:47:32, Miguel A. Ballicora wrote:
>Besides the wording, Giancarlo's point was clear. Do the programs "understand"
>what's going on? Sometimes you avoid a6 because there so many good choices
>that a program took a anyone. Still does not prove that that the program
>understand the position.
I agree. Also, I think (after a small experiment) in the discussed positions
even stalemate detection in qsearch cannot help too much.
>This is an attempt to make it harder for the programs
>
>2k2r2/2P3R1/pP6/1P6/8/8/1K6/8 w - - 0 56
>
>White should avoid bxa6. With enough time (and maybe table bases) programs
>will avoid it because they will see a promotion in other line (Kb3 or Kc3) but I
>guess that it will take many plies to find that, unless the program "understand"
>the risk of playing bxa6.
For Yace, this is indeed much more difficult than the position of GCP. This is
what I get on my AMD k6-2 475, 20M hash, KRPKR and all 4-men TBs:
nodes time score depth
3738030 51.552 5.19 14. 56.bxa6 Rf2+ 57.Kc3 Rf3+ 58.Kd4 Rf4+ 59.Kd3
Rf3+ 60.Ke4 Rf4+ 61.Ke3 Rf3+ 62.Ke4 Rf4+ 63.Ke3
Rf3+ 64.Ke4 {240}
3918788 52.443 4.79 15-- 56.bxa6 Rf2+ 57.Kc3 Rf3+ 58.Kd4 Rf4+ 59.Kd3
Rf3+ 60.Ke4 Rf4+ 61.Kd5 Rf5+ 62.Kd6 Rf6+ 63.Ke7
Re6+ 64.Kf7 Rf6+ 65.Ke8 Rxb6 66.Rg6 Rxg6 67.a7
Re6+ 68.Kf7 Kxc7 69.a8=Q Rd6 70.Qa6 {501}
4352747 54.754 0.06 15t 56.bxa6 Rf2+ 57.Kc3 Rf3+ 58.Kd4 Rf4+ 59.Kd3
Rf3+ 60.Ke4 Rf4+ 61.Kd5 Rf5+ 62.Kd6 Rf6+ 63.Ke7
Re6+ 64.Kf8 Rf6+ 65.Rf7 Rxb6H 66.a7H Ra6H
67.a8=Q+H Rxa8H 68.Ke7H Kxc7H 69.Ke6+H Kc6H
70.Rd7H {0}
6620877 1:40.7 0.07 15t+ 56.Kc3 axb5
24951055 3:54.6 5.59 15++ 56.Kc3 axb5 57.Rg6 Rh8 58.Rd6 Re8 59.Kb4 Rh8
60.Rd8+ Kb7
38439546 5:27.3 5.59 15t 56.Kc3 a5 57.Rg6 a4 58.Rd6 a3 59.Kb3 a2 60.Kxa2
Rg8 61.Ka3 Rh8 62.Ka4 Kb7 63.Rd8H Rxd8H
64.cxd8=N+H {HT} {500}
43729283 6:26.9 5.60 15t+ 56.Kb3 a5 57.Rg6 Kd7 58.Ka4 Rh8 59.Kxa5 Ra8+
60.Kb4 Rf8 61.Rg7+ Ke6
53016052 7:32.1 5.66 15t 56.Kb3 axb5 57.Rg6 Kb7 58.Rd6 Ka6 59.Kc3 Rf3+
60.Rd3 Rf8 61.Rd8 Rf3+ 62.Kd4H Rf4+H 63.Kd5H
Rc4H 64.Rb8H Rc3H 65.c8=Q+H Rxc8H {HT} {0}
56867189 8:10.7 5.67 15t+ 56.Rg6 axb5 57.Rd6 b4
61843690 8:45.4 9.24 15t 56.Rg6 axb5 57.Rd6 b4 58.Kb3 Rg8 59.Kxb4 Kb7
60.Rd8 Rg4+ 61.Kc5 Rg5+ 62.Kd6 Rg6+ 63.Kd7 Rg7+
64.Ke8 Rxc7 65.bxc7 {HT} {580}
63260777 9:01.4 9.24 15. 56.Rg6 axb5 57.Rd6 b4 58.Kb3 Rg8 59.Kxb4 Kb7
60.Rd8 Rg4+ 61.Kc5 Rg5+ 62.Kd6 Rg6+ 63.Kd7 Rg7+
64.Ke8 Rxc7 65.bxc7 {HT} {580}
Moves, that have added a H are taken from the hash at display time, and are
therfore not reliable.
Without TBs I get essentially the same, but faster for this position.
For Gian Carlo's position
2k2r2/2P3R1/1P6/P7/8/1K6/8/8 w - - 0 56
I get:
477157 3.628 5.15 11t 56.a6 Rf3+ 57.Kc4 Rf4+ 58.Kd5 Rf5+ 59.Kd4 Rf4+
60.Ke5 Rf5+ 61.Ke4 Rf4+ 62.Kd5H Rf5+H 63.Kd4H
Rf4+H 64.Ke5H Rf5+H 65.Ke4H Rf4+H 66.Kd5HR {240}
695700 4.992 5.16 11t+ 56.Kc4 Kb7 57.Rg5 Ka6 58.Kd5 Rf3
771840 5.473 5.55 11++ 56.Kc4 Kb7 57.Rg5 Ka6 58.Rb5 Rg8 59.b7 Rg4+
60.Kd5 Rg5+ 61.Ke6 Rxb5 62.c8=Q Rxa5 {581}
1056002 7.201 8.25 11t 56.Kc4 Kb7 57.Rg5 Ka6 58.Rd5 Rh8 59.Rd8 Rh4+
60.Kd5 Rh5+ 61.Ke6 Rh6+ 62.Kf7 Rc6 63.c8=Q+
Rxc8H 64.Rxc8H Kxa5H {580}
1800604 12.937 8.25 11. 56.Kc4 Kb7 57.Rg5 Ka6 58.Rd5 Rh8 59.Rd8 Rh4+
60.Kd5 Rh5+ 61.Ke6 Rh6+ 62.Kf7 Rc6 63.c8=Q+
Rxc8 64.Rxc8 Kxa5 {580}
2238860 15.955 8.65 12++ 56.Kc4 Kb7 57.Rg5 Ka6 58.Rd5 Rh8 59.Rd8 Rh4+
60.Kd5 Rh5+ 61.Kc6 Rh6+ 62.Rd6 Rh5 63.c8=Q+
Kxa5 {1081}
2456093 17.637 8.91 12t 56.Kc4 Kb7 57.Rg5 Ka6 58.Rc5 Rc8 59.Rd5 Rf8
60.Rd8 Rf4+ 61.Kd3 Rf3+H 62.Ke2H Rc3H 63.c8=RH
{660}
and after a6 (and clearing hash tables):
833143 6.520 -5.21 13. 56...Rf3+ 57.Kc4 Rf4+ 58.Kd5 Rf5+ 59.Ke4 Rf4+
60.Kd3 Rf3+ 61.Kd4 Rf4+ 62.Ke3 Rf3+ 63.Ke4 Rf4+
64.Ke5 Rf5+ 65.Ke4 Rf4+ {-240}
1178667 8.144 -4.81 14++ 56...Rf3+ 57.Kc4 Rf4+ 58.Kd5 Rf5+ 59.Ke4 Rf4+
60.Kd3 Rf3+ 61.Kd4 Rf4+ 62.Kc5 Rf5+ 63.Kc6 Rf6+
64.Kb5 Rxb6+ 65.Kc5 Rxa6 66.Rg8+ Kxc7 67.Rg7+
Kb8 68.Kb5 Rd6 69.Kc5 {0}
1541179 10.346 -4.81 14t 56...Rf3+ 57.Kc4 Rf4+ 58.Kb5H Rf5+H 59.Ka4H
Rf4+H 60.Ka5H Rf5+H 61.Ka4H Rf4+H 62.Ka5H Rf5+H
63.Ka4HR {-240}
1549020 10.472 -4.81 14. 56...Rf3+ 57.Kc4 Rf4+ 58.Kb5 Rf5+ 59.Ka4 Rf4+
60.Ka5 Rf5+ 61.Ka4 Rf4+ 62.Ka5 Rf5+ 63.Ka4
{-240}
1868777 11.915 -4.41 15++ 56...Rf3+ 57.Kc4 Rf4+ 58.Kb5 Rf5+ 59.Ka4 Rf4+
60.Ka3 Rf3+ 61.Kb2 Rf2+ 62.Kc1 Rf1+ 63.Kd2 Rf2+
64.Ke3 Rf3+ 65.Kd4 Rf4+ 66.Ke5 Rf5+ 67.Ke6 Rf6+
68.Ke7 Re6+ 69.Kf8 Rf6+ 70.Ke8 Rxb6 71.Rg8 Rxa6
72.Rg7 {-80}
3171215 17.690 -0.05 15t 56...Rf3+ 57.Kc4 Rf4+ 58.Kb5 Rf5+ 59.Kc6 Rf6+
60.Kc5 Rf5+ 61.Kd4 Rf4+ 62.Ke5 Rf5+ 63.Ke6 Rf6+
64.Ke7 Re6+H 65.Kf8H Rxb6H 66.Rf7H Rxa6H {HT}
[...]
11233200 1:00.3 0.00 19t 56...Rf3+ 57.Kc4 Rf4+ 58.Kb5 Rf5+ 59.Kc6 Rf6+
60.Kc5 Rf5+ 61.Kd4 Rf4+ 62.Ke5 Rf5+ 63.Kd6 Rf6+
64.Ke7 Re6+ 65.Kxe6H {-740}
I think, more aggressive extensions for check (in rook endgames, Yace will not
do too many extenions for this) could help to "understand" the positions better.
Regards,
Dieter
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