Author: Uri Blass
Date: 08:54:15 02/28/03
Go up one level in this thread
On February 28, 2003 at 11:05:21, Amir Ban wrote: >On February 28, 2003 at 03:11:41, Uri Blass wrote: > >>On February 27, 2003 at 20:23:39, Amir Ban wrote: >> >>>On February 26, 2003 at 18:48:53, Stephen Ham wrote: >>> >>>>Thanks, >>>> >>>>Dann, Uri, and Robin! I think I understood all of that. That was very helpful. >>>>Again, I'm know next to nothing about chess engine programing, so I assumed that >>>>the evaluation function guided the search function. I don't know why I assumend >>>>that...I just did. >>>> >>> >>>Of course the evaluation guides the search. Since you got here various answers >>>that basically say evaluation is not that important I will add a view that >>>strongly disagrees. Getting evaluation right is the most important thing for a >>>program to do in a position. Under-evaluation will often lead to playing weak >>>moves, but over-evaluation is almost always fatal against an opponent who has >>>the right assessment. >>> >>>Amir >> >>I have some comments here >> >>1)Evaluation is not only to be more correct in score but to choose better moves. > >That's almost the same. I'm not arguing with that if there's only one good move >in a position a program will choose it regardless of its evaluation, but given >half a chance a program with incorrect evaluation will get it wrong. > > >>If you add to your evaluation a random small noise the result may be worse >>than if you add a constant. >> > >There are transformations to the scores that do not change the meaning of the >evaluation. Any linear mapping is one of them. Actually any mapping that >preserves order doesn't matter in principle. > >This doesn't mean that evaluation is not important. > > >>2)I think that evaluation is one of the main things but it is not clear that >>it is more important than search. >> >>If you make the program 3 times faster thanks to better search rules(I mean >>something eqvivalence because I do not expect better search rules to give the >>same improvement in every position) then it is a big improvement(I believe that >>the potential is practically bigger). >> > >Bigger than what ? Bigger than being 3 times faster. I believe that it is possible to get more than you can get from being 3 times faster by only better search rules without changing the evaluation. > > >>3)If I understood correctly most of your work from Junior5 is about evaluation. >> >>It may be interesting to know if Junior8 can beat Junior5 with time odds of 3:1 >>(it is possible to say +200% for one engine in engine matches) >> >>I believe that it will be the case only if the time control is long enough >>but again I think that better search rules with the same evaluation may give >>exponential improvement when the time control is slower. >> >>4)The problem is that practically you cannot seperate between the 2 and >>say that the evaluation gave you x elo and the search gave you y elo because >>it is possible that a change in the search rules is productive only thanks to >>better evaluation. >> > >Tell me about it :) The fact that things are complicated and interconnected >doesn't mean that we should not discuss them. > >Amir Parameters for search rules may be dependent on evaluation. null move pruning is one example. The question if to use R=2 or R=3 may be dependent on the evaluation. My point is that it is possible that you could do a positive change on the search rules thanks to changes in your evaluation . Uri
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