Author: Uri Blass
Date: 04:12:30 08/03/03
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On August 03, 2003 at 06:54:47, Jonas Bylund wrote: >On August 03, 2003 at 06:50:25, Uri Blass wrote: > >>On August 03, 2003 at 05:45:42, emerson tan wrote: >> >> >>> Of course given enough depth, most chess >>>programs can give good evaluation, but there are still a lot of positions that >>>are far beyond the search depth of top engines on the most powerful hardware, >>>and it is here where chess knowledge is needed. >> >>Based on my understanding increasing the chess knowledge in Rebel is not going >>to help it to understand these positions. >> >>I understood that >>Rebel does the full evaluation at every node except the leaves so I guess that >>if it can see something important in the tree before the leaves then it is going >>to see it also in the leaves. >> >>Cases when something important is generated only in the leaves can be detected >>with less chess knowledge (maybe even faster) thanks to deeper search. >> >>In order to change my mind >>I need to see a case when knowledge does not help to detect the problem one or 2 >>plies earlier but help to detect the problem 10 plies earlier. >> >>If Rebel with full knowledge say +1 for white at plies 5-10 when default Rebel >>say evaluations near +1 for black at plies 5-15 then it is going to be a >>convincing evidence that knowledge in Rebel is what you think about when you use >>that word. >> >>Uri > >But how can we know without trying it? > >This has the potential to be a very interesting experiment! > >Jonas I know that people tried personalities with Rebel century and found that reducing the knowledge of Rebel lead to better results. There was no difference that was observed between blitz and longer time control(Ed did not say based on tests to use knowledge=25 in blitz and knowledge=50 at long time control). I see no reason to believe that things changed. I do not claim that knowledge is not important but that I believe that the name knowledge in Rebel is simply misleading because Rebel does the full evaluation in every node when the remaining depth is positive based on Ed's page. I believe that the lazy evaluation at the leaves miss nothing big that was detected in the previous plies so there is no case that Rebel with knowledge can do clearly better than Rebel without knowledge(in the best case for the full knowledge evaluation it can only find that it is in trouble faster but there are more cases when it can find that it is in trouble faster when the default personality is used) I guess that it may also miss a small positional difference that it does not consider in the lazy evaluation but the important thing in the evaluation is not to miss a big thing and deeper search by 1 ply often more than compensate for a small positional difference. I am not Ed and I may be wrong but if you want to prove that I am wrong then it is better that you start by provifing a position when default Rebel show clear advantage for white at depthes 5-15 when Rebel with maximal knowledge shoe something completely different at depth 5-10. Uri
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