Author: blass uri
Date: 08:41:00 07/19/00
Go up one level in this thread
On July 19, 2000 at 08:14:56, Amir Ban wrote: >On July 19, 2000 at 03:55:44, blass uri wrote: > >>On July 18, 2000 at 19:10:46, Amir Ban wrote: >> >>>On July 18, 2000 at 14:05:46, Jeroen Noomen wrote: >>> >>>>On July 18, 2000 at 09:29:12, Amir Ban wrote: >>>> >>>>Amir, >>>> >>>>I agree that Junior earned its points honestly. I also agree with most you write >>>>about these games. Still, you don't point out anything about the losses against >>>>Kramnik and Piket. And that was exactly what I had in mind writing this thread. >>>>Those two games showed exactly where chess computer programs still can be >>>>improved. And HAVE to be improved, otherwise human GM's will have good chances >>>>to get more points next year. And they will, because they have learnt. >>>> >>>>IMO if you solve most of the problems about king's attacks and closed positions, >>>>then it will be almost impossible for the strongest GM's ta beat a computer. >>>>Because in that case they have no advantage in any type of position anymore. But >>>>in 2000 there is still not much to be done when a clever player manages to block >>>>the position or start a slow attack: The programs do not know about this and >>>>only human mistakes will save them. >>>> >>>>So the crucial question is: When will one of the leading programmer stop >>>>searching for higher NPS, better searching techniques etc? When somebody will >>>>REALLY tackle the 2 problems I mentioned? Because otherwise a computer can still >>>>be beaten in 2010, running on 500 GHz. But as I already mentioned: This is the >>>>computerchess paradox: NOBODY wants to sac NPS for more knowledge. And as long >>>>as nobody wants to quit this 'rule', human GM's are still superior in knowledge >>>>and understanding of the game. >>>> >>>>Jeroen >>>> >>> >>>The speed vs. knowledge dilemma is a false one. It may apply to Rebel and other >>>programs, but it doesn't apply to Junior, where I have a framework to code >>>evaluation stuff virtually for free. >> >>2 questions: >>1)I guess that the fact that you can add evaluation stuff virtually for free >>in run time make adding knowledge to the evaluation less simple and you need >>more time to do the design decisions to change the evaluation function relative >>to other programs. >> >>Am I correct? >> > >No If it is simple to change the evaluation then what is the reason for some mistakes in the evaluation of Junior6a(for example that in some positions it does not evaluate stalemates correctly and can say mate against itself when there is a stalemate combination). I can also see that Junior cannot see at evaluation time things that Crafty or Hiarcs can see at evaluation time(at least for Junior5.9) [D]8/8/p7/pp6/7P/k7/8/K7 w - - 0 1 Junior5.9 at depth 3 cannot see that white is winning when Hiarcs and Crafty have no problem to do it at depth 1. It is not relevant in this position but Junior may need more plies to see the problem in more comlicated position. > > >> >> >>2)I know that Junior6a does not have a trapped knight code at least in part of >>the positions. >>Here is one position that demonstrates it from the game Junior6a-tal(15 minutes >>per move with no pondering) >> >>[D]r4rk1/pp1n1pbp/2p1p1p1/3nP3/2B2P1q/2N4P/PPPBQP2/2KR3R w - - 0 1 >> >>Junior blundered by 14.Qg4 and only after 14...Qxf2 it understood that it lost a >>pawn(15.Bxd5 cxd5 16.Nxd5 h5 17.Qg1 Qxg1 18.Ne7+ is bad because the knight is >>trapped in e7). >> >> >>Can you evaluate this stuff virtually for free? >> > >In principle yes, but I wouldn't do it in this case because it's not clear how >to formulate it. The knight is not really trapped. It can be defended by >friendly pieces. There may be a bishop on c8 that could be exchanged for it. If there is a bishop at c8 then a good evaluation can say that the knight is not trapped. The knight is trapped if there is no good square to go and if there is a bishop at c8 the knight has a good square to go. In >the late endgame with few pieces on board the knight would not be trapped at all >because the back rank is free, etc. etc. > >It's a common error to code an evaluation term with a specific position in mind, >and then find that your program applies it in dozens of positions where you >don't want it applied. I thought that the knight is trapped because there was no square in knight distance that is not defended by a pawn or defended and not attacked by the white pieces Every square that is not defended by a pawn is defended by 2 pieces and not only one piece and this fact increase the suspect that the knight is trapped. The question is if in similiar cases the knight is often trapped. If it is trapped in 1/2 or 1/3 of the similiar cases then it may be enough to be a good afraid to be afraid from Qg4. I do not suggest to change the evaluation by a very big score because assuming that the knight is trapped when it is not clear is also a problem but even a small change may be enough to avoid Qg4. Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.