Author: blass uri
Date: 10:22:31 06/19/00
Go up one level in this thread
On June 19, 2000 at 11:47:12, Ed Schröder wrote: >On June 19, 2000 at 04:45:33, blass uri wrote: > >>On June 19, 2000 at 03:03:49, Ed Schröder wrote: >> >>>On June 18, 2000 at 19:46:03, Dave Gomboc wrote: >>> >>>>On June 18, 2000 at 18:21:01, Ed Schröder wrote: >>>> >>>>>On June 18, 2000 at 16:34:16, blass uri wrote: >>>>> >>>>>>On June 18, 2000 at 12:00:08, Ed Schröder wrote: >>>>>> >>>>>>>On June 18, 2000 at 10:36:40, Gian-Carlo Pascutto wrote: >>>>>>> >>>>>>>>On June 18, 2000 at 10:17:08, Ed Schröder wrote: >>>>>>>> >>>>>>>>>According Rebel it is a mate in 10. >>>>>>>>> >>>>>>>>>Ed >>>>>>>>> >>>>>>>>>00:00 07.00 0.81 1.Rxh5 gxh5 2.Rxh5 Kf8 3.Rxh7 Ke8 4.Rh8+ Kd7 5.Qf5+ Kc7 >>>>>>>>>00:01 08.00 2.37 1.Rxh5 gxh5 2.Rxh5 Kf8 3.Rxh7 Ke8 4.Qf5 Kd8 5.Qxf7 Kc8 >>>>>>>>>6.Qxe7 >>>>>>>>>00:03 09.00 2.47 1.Rxh5 gxh5 2.Rxh5 Kf8 3.Rxh7 Ke8 4.Qf5 Kd8+ 5.Qxf7 Kc7 >>>>>>>>>6.Qxe7+ Kc8 >>>>>>>>>00:43 10.00 11.74 1.Rxh5 gxh5 2.Rxh5 Kf8 3.Rxh7 e6 4.Bf6 Ke8 5.dxe6 Qxc4+ >>>>>>>>>6.Qxc4 >>>>>>>>>02:35 11.00 Mate in 10 moves 1.Rxh5 Kf8 Rxh7 2.Ke8 Rxf7 3.Qxc4 Qxc4 4.g5 Rhh7 >>>>>>>>>5.b5 Rxe7+ 6.Kd8 >>>>>>>> >>>>>>>>I find it interesting to notice that even Rebel has some trouble with this, >>>>>>>>taking more than 10 times as much time to resolve the 10th ply. >>>>>>> >>>>>>>That's pretty normal whith such big score differences (2.47 -> 11.74) as >>>>>>>search is confrontated with big score fluctuations which causes move >>>>>>>ordering to collapse. I wouldn't bother too much about it, it's quite >>>>>>>normal. >>>>>> >>>>>>Not for all programs. >>>>> >>>>>Of course. >>>>> >>>>>>Chessmaster6000(ss=10) can see a forced mate in only 4 seconds and does not have >>>>>>a big branching factor >>>>> >>>>>Sure. Maybe not in this position. >>>>> >>>>>>This is normal for chessmaster to see mates clearly faster than other programs >>>>>>and I think that this is because the other programs do some mistakes in their >>>>>>search rules. >>>>> >>>>>Nope. Johan has special (mate) stuff in his search no program has. >>>>> >>>>>Ed >>>> >>>>Just curious... why don't you add it to Rebel too? :-) >>> >>>a) because I don't know "exactly" what it is; >>>b) too much emphasis on mates loses too much elo points in games. >>> >>>Ed >> >>I think reason a is the right reason because I do not think that chessmaster >>loses too much elo points in games(chessmaster6000 is one of the top programs >>and is only one point behind Fritz5.32 in the ssdf list inspite of having no >>learning function and having an older engine) >> >>I believe that having special mate stuff is productive for chess programs if you >>do it in the right way. > >The right way? Now tell me what that is... You might ask yourself the >question if such a thing exist in computer chess. > >Finding deep mates requires extensions. Extensions mean a higher branch >factor. A higher branch factor means a lower search depth. A lower search >depth means a lower elo. The right way is to do it almost without a lower search depth. In order to do it you need to do the extensions only in the right places so when there is no mate danger you will not have lower search depth. You can also decide to have a time limit for searching with the extensions(for example 1/10 of the time per move). > >So far so good. The question remains if the gain in elo seeing deep mates >is higher than the loss in elo because of the lower search depth. IMHO you >better can put your cards on the deeper search depth. Show me one game >where ChessMaster is able to win because of the deep mate stuff. You will >have a hard time finding one or two games. Why is that? It just doesn't >happen because the other comps see deep enough to avoid the trouble. Cases >you can win a game by a nice piece sacrifice the other comp didn't see are >seldom to none these days. I remember a game when chessmaster won insomaniac This is the relevant position: [D]3r2k1/pp2nppp/1q1br3/8/3N4/1P1pP3/P2P1PPP/RQB2RK1 b - - 0 1 Chessmaster6666 found 23...Bxh2+ and won(24.Kxh2 Rh6+ 25.Kg1 Rxd4 26.exd4? Qd6 27.f3 Qxd4+ 28.Rf2 Nf5...) I do not know if it happens often but I believe that it can happen often if you play for king attacks. It is not rare in chess sysytem tal's games. Uri
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