Author: Ed Schröder
Date: 01:11:32 06/20/00
Go up one level in this thread
On June 20, 2000 at 02:12:32, blass uri wrote: >On June 19, 2000 at 19:02:51, Ed Schröder wrote: > >>On June 19, 2000 at 13:22:31, blass uri wrote: >> >>>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. >> >>The right way to do it ussue again. Ever tried to do it yourself? >>If not try it yourself and let's talk again 4-5 years later. > >I did not say that it is easy to do it. >> >> >>>You can also decide to have a time limit for searching with the extensions(for >>>example 1/10 of the time per move). >> >>Tried it? > >No >I did not say it is easy to do it but only that I believe that it is possible. >I guess that there are more important things for you to do in the near future. > >> >>It's no good. In fact it is a non working idea. When you for instance >>find something interesting in the first part with many extensions you >>will lose it as soon as you go back to normal search. Now that looks >>real silly for a chess program that after (say) ply 5 finds a nice >>tactical shot and then fails low on the 6th ply and then finds the >>combination back on ply 9 or 10. > >This was not what I meant. >I did not think to forget about what you found. >Of course if you find something intersting(a fail high or a fail low) there is >no reason to forget it and you can choose between only avoid doing extensions in >nodes that you did not search and if there is a problem with doing it to >continue with the extensions. And that is exactly the point. Of course you will find thousand and 10 thousands of interesting cases you are forced to "remember" while having no single effect on the best move. All these 10 thousands of useless extensions are needed to extend again every iteration resulting in time loss only. When you invest (say) 10% of the allowed time in a special tactical search and it brings you nothing (which is true for almost every try) then you don't end up with a 10% loss but with a percentage that is much higher because of all the extensions you have to "remember". If you are lucky you will end up with a total loss of 15-20% in a quiet position. If you have bad luck search performance will drop with a factor of 2-3. Ed >If you do not find something interesting you can forget about the extensions. >I think that it may be better in a correpondence game to use chessmaster for >1/10 of the time when I suspect that there may be a mate danger and if >chessmaster does not see something interesting to use another program for 9/10 >of the time. > >I believe that it is better than to use only the other program. >If I am right then the other program could be better if it knew to do the same > >Uri
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