Graham Banks wrote:bob wrote:Alexander Schmidt wrote:bob wrote:For the record, the horizon-effect will not go away until a program can see to the end of the game.
Of course there is always a horizon for the programms, but when we are talking about bad moves due to horizon effects, we talk about unforced material loses.
A horizon effect can and will cause problems at the root, otherwise it is not an issue. It is being used to push some consequence over the horizon so that the effect is hidden. The farther this occurs from the root, the greater the probability that you can change your mind before entering such a forced sequence of moves not knowing about the eventual bad outcome. But no matter what, this influences the score at the root, because you play a root move assuming that the path to the terminal node you like is optimal for both sides. If you suddenly find your key move can't be played, farther down in the game, then you are going to be forced away from the original score you were playing toward and have to accept something worse. How much worse? Impossible to say, obviously. But it could lead to material loss. Or just a positional bust that still causes you to lose the game later.
Bob - would you regard the following as an example of the horizon effect at play?
[Event "World Regional Teams Championship 2010"]
[Site "Auckland"]
[Date "2010.09.20"]
[Round "4.17"]
[White "spark-0.4"]
[Black "Chronos 1.9.9"]
[Result "1-0"]
[ECO "E55"]
[Annotator "0.60;0.15"]
[PlyCount "51"]
[EventDate "2010.09.10"]
[EventType "tourn"]
[Source "Banks"]
[TimeControl "40/1500:40/1500:40/1500"]
{Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz 0 MHz W=19.6 ply; 1,893kN/s;
HS-Masterbook 2.0.ctg B=17.8 ply; 702kN/s; HS-Masterbook 2.0.ctg} 1. d4 {
[%eval 35534,0] [%emt 0:00:00]} Nf6 {[%eval 35534,0] [%emt 0:00:00]} 2. c4 {
[%eval 35534,0] [%emt 0:00:00]} e6 {[%eval 35534,0] [%emt 0:00:00]} 3. Nc3 {
[%eval 35534,0] [%emt 0:00:00]} Bb4 {[%eval 35534,0] [%emt 0:00:00]} 4. e3 {
[%eval 35534,0] [%emt 0:00:00]} c5 {[%eval 35534,0] [%emt 0:00:00]} 5. Bd3 {
[%eval 35534,0] [%emt 0:00:00]} O-O {[%eval 35534,0] [%emt 0:00:00]} 6. Nf3 {
[%eval 35534,0] [%emt 0:00:00]} d5 {[%eval 35534,0] [%emt 0:00:00]} 7. O-O {
[%eval 35534,0] [%emt 0:00:00]} dxc4 {[%eval 35534,0] [%emt 0:00:00]} 8. Bxc4 {
[%eval 35534,0] [%emt 0:00:00]} Nbd7 {[%eval 35534,0] [%emt 0:00:00]} 9. Qe2 {
[%eval 35534,0] [%emt 0:00:00]} b6 {[%eval 35534,0] [%emt 0:00:00]} 10. Rd1 {
[%eval 35534,0] [%emt 0:00:00]} cxd4 {[%eval 35534,0] [%emt 0:00:00]} 11. exd4
{[%eval 35534,0] [%emt 0:00:00]} Bb7 {[%eval 35534,0] [%emt 0:00:00]} 12. d5 {
[%eval 35534,0] [%emt 0:00:00]} Bxc3 {[%eval 15,16] [%emt 0:00:50]} 13. dxe6 {
[%eval 60,18] [%emt 0:00:43]} Bxf3 {[%eval 2,16] [%emt 0:00:50]} 14. gxf3 {
[%eval 54,19] [%emt 0:01:16]} fxe6 {[%eval 16,17] [%emt 0:00:50]} 15. Bxe6+ {
(bxc3) [%eval 49,18] [%emt 0:01:21]} Kh8 {[%eval 2,17] [%emt 0:00:50]} 16. bxc3
{[%eval 40,19] [%emt 0:01:36]} Re8 {(Qe8) [%eval -1,16] [%emt 0:00:50]} 17. Rd3
{(Ba3) [%eval 41,19] [%emt 0:00:55]} Nh5 {(Qc7) [%eval 14,17] [%emt 0:00:50]}
18. Qe4 {[%eval 58,20] [%emt 0:01:01]} Nhf6 {(Qf6) [%eval 26,18] [%emt 0:00:50]
} 19. Qf5 {[%eval 0,21] [%emt 0:01:30]} Qe7 {[%eval 39,17] [%emt 0:00:50]} 20.
Bxd7 {(Re3) [%eval 444,18] [%emt 0:00:44]} Qe1+ {[%eval 260,16] [%emt 0:03:20]}
21. Kg2 {[%eval 339,2] [%emt 0:00:00]} Re5 {(Re2) [%eval 402,15] [%emt 0:00:43]
} 22. Bd2 {(Be3) [%eval 570,19] [%emt 0:00:35]} Qe2 {
[%eval 445,18] [%emt 0:00:53]} 23. Re1 {[%eval 609,22] [%emt 0:01:05]} Qxe1 {
(Rxf5) [%eval 467,18] [%emt 0:00:42]} 24. Bxe1 {[%eval 635,22] [%emt 0:00:42]}
Rxf5 {[%eval 488,19] [%emt 0:00:42]} 25. Bxf5 {[%eval 645,23] [%emt 0:00:59]}
Re8 {(g6) [%eval 490,18] [%emt 0:00:42]} 26. Re3 {[%eval 672,22] [%emt 0:01:01]
} 1-0
:
)