Author: Tony Werten
Date: 11:15:46 11/05/03
Go up one level in this thread
On November 05, 2003 at 11:58:18, Christophe Theron wrote: >On November 05, 2003 at 03:03:19, Tony Werten wrote: > >>On November 04, 2003 at 13:58:29, Christophe Theron wrote: >> >>>On November 04, 2003 at 02:43:34, Tony Werten wrote: >>> >>>>On November 03, 2003 at 13:22:42, Christophe Theron wrote: >>>> >>>>>On November 03, 2003 at 10:04:32, Will Singleton wrote: >>>>> >>>>>>On November 03, 2003 at 02:35:09, Gerd Isenberg wrote: >>>>>> >>>>>>>On November 03, 2003 at 02:33:02, Gerd Isenberg wrote: >>>>>>> >>>>>>>>On November 02, 2003 at 17:12:38, Will Singleton wrote: >>>>>>>> >>>>>>>>>On November 02, 2003 at 16:52:49, Gerd Isenberg wrote: >>>>>>>>> >>>>>>>>>><snip> >>>>>>>>>>>In the same vein, the following position has always been a nightmare for Tiger: >>>>>>>>>>> >>>>>>>>>>>[D]8/1KP5/3q2k1/8/6p1/8/8/8 b - - >>>>>>>>>>> >>>>>>>>>>>This position comes from a real game between the Modular Game System Sargon 2.5 >>>>>>>>>>>and Mike III, played in September 1980 during the Personal Computer World Fair. >>>>>>>>>>>Mike III continued the game with a long series of checks leading to a draw. >>>>>>>>>>> >>>>>>>>>>>Chess Tiger is not smarter than Mike III here. It is something that I had fixed >>>>>>>>>>>in the 16 bits version, to the expense of some added complexity in the passed >>>>>>>>>>>pawns evaluation code. I have not transfered this code to the 32 bits version >>>>>>>>>>>because it was not general enough (add another black pawn and the code did not >>>>>>>>>>>work). >>>>>>>>>>> >>>>>>>>>>>I am interested in results of other (amateur and commercial) programs. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Christophe >>>>>>>>>> >>>>>>>>>>Hi Christophe, >>>>>>>>>> >>>>>>>>>>IsiChess on AMD XP2.6+ first shuffles around with Qb4+, Qxc7 and Qd7. >>>>>>>>>>After 5 seconds at depth 13 Qxc7 came up. Mate in 14 resp. 12 after one minute >>>>>>>>>>and 1:10. I guess a matter of won KPK eval. >>>>>>>>>> >>>>>>>>>>Cheers, >>>>>>>>>>Gerd >>>>>>>>> >>>>>>>>>Sure, but I'm not sure CT was referring to finding the mate as the problem. CT >>>>>>>>>seems to have some problem understanding that KQK is better than KQKP, that's >>>>>>>>>all I can figure. >>>>>>>>> >>>>>>>>>Will >>>>>>>> >>>>>>>you mean won KPK against KQPKP? I use interior node recognizers and assign >>>>>>>shlightly more than queen advantage in won KPK. Additionaly there is a >>>>>>>heuristic, that reduces score a bit (e.g. abs(delta material) / X) if a lot of >>>>>>>checks occur with "no progress". >>>>>>> ^^^^ >>>>>>>Gerd >>>>>> >>>>>>I do that too, but it's constrained to several consecutive checks that don't >>>>>>reset the fifty-move counter. Seems to help in some positions, but I'm not sure >>>>>>how generally effective it is. >>>>>> >>>>>>Will >>>>> >>>>> >>>>> >>>>>That's exactly what I have tried, with different values for X and the number of >>>>>consecutive checks needed to trigger it. >>>>> >>>>>It has always weakened my program. Not by much, but I expected a minor gain, not >>>>>a minor loss! >>>> >>>>Make sure your trigger is counted from the back, not the front. ( I don't want >>>>to make it too easy :) >>>> >>>>Tony >>> >>> >>> >>>I really don't understand what you mean... >> >>Whatever adjustments you do after no progress, it is only important if the last >>fe 5 moves made no progress (or gave checks). If the first 5 moves did this and >>then there is a no-check or capture you should do nothing. >> >>If you trigger from the front (ie root) you'll seriously weaken the engine >>because sometimes it is nescessairy to shuffle some pieces around before doing >>something, but you will be giving a penalty for that. >> >>Tony > > > >Oh yes. That's how I did it. When I reach a leaf I check if the last X plies >where just checks without capture (X=10..12). > >Probably my definition of "no progress" was not restrictive enough. For example >if there is a pawn push, it is not a case of "no progress" I guess. I would call that a clear sign of progress :) It's not going to make all horizon effects go away, but it does take care of a few annoying ones. And it makes you look like a fool less often. I think I decided to implement this after a draw with Gandalf at IPCC in a won position. Tony > > > > Christophe
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