Author: Vasik Rajlich
Date: 02:14:42 01/13/06
Go up one level in this thread
On January 12, 2006 at 09:33:04, Albert Silver wrote: > >>>>>>>Noomen-RybkaB9Neutral-Fruit22 2006 >>>>>>> >>>>>>>1 Rybka 1.01 Beta 9 32-bit 2900 +6 +34/-21/=25 58.13% 46.5/80 >>>>>>>2 Fruit 2.2 2850 -6 +21/-34/=25 41.88% 33.5/80 >>>>>>> >>>>>>>The GUI said Rybka performed 56 Elo over Fruit 2.2 using the Neutral settings. >>>>>>> >>>>>>>Noomen-RybkaB9Optimistic-Fruit22 2006 >>>>>>> >>>>>>>1 Rybka 1.01 Beta 9 32-bit 2900 +52 +36/-13/=31 64.38% 51.5/80 >>>>>>>2 Fruit 2.2 2850 -52 +13/-36/=31 35.63% 28.5/80 >>>>>>> >>>>>>>Here the GUI said Rybka performed 102 Elo over Fruit 2.2 using the Optimistic >>>>>>>settings. >>>>>>> >>>>>>>In order to gather more data I'll run a shorter Nunn2 match (only 40 games) >>>>>>>against Gambit Fruit 4bx, which had been the first Beta's toughest opponent in >>>>>>>the Nunn2 set aside from Fruit 2.2 in my testing. >>>>>>> >>>>>>>The rating of 2850 for Fruit was taken from the latest SSDF list, and Rybka's >>>>>>>2900 was chosen arbitrarily. >>>>>It is also possible that optimistic is simply better against weaker players when >>>>>neutral is better against stronger players or players of the same strength. >>>>> >>>>>The way to test it is to give fruit more time(in case of ponder off) or better >>>>>hardware in case of ponder on) and to test both optimistic and neutral. >>>>> >>>>>Uri >>>> >>>>Another possibility (which we will test with Beta 10) is that optimistic is >>>>better in better positions. I will try an "adaptive" approach, where if the >>>>previous iteration gave a score above a section threshold, an optimistic setting >>>>is used. >>>> >>>>Vas >>> >>> >>>Maybe, maybe not. Note that in the above results, Optimistic only won two more >>>games than Neutral. The biggest difference is that it lost far fewer. >>> >>> Albert >> >>Indeed, maybe I will look at that when all the data is ready. >> >>The adaptive approach is something which makes some sense to me. It will work if >>it's true that in better positions, you are more likely to find a move which >>becomes stronger with a deeper search. >> >>Yes, it's a mouthful - I hope it makes sense :) >> >>Vas > >I understood fine, but after a little thought, taking into consideration the >above results, I am not sure the logic follows. The idea as I understand it, is >to basically be more attentive to one's own winning possibilities when winning, >and the opponent's when worse. At first view this seems entirely logical, but is >it? Looking for one's own 'winning' possibilities really means moves that appear >to possibly improve one's position substantially. How much is that threshold? >What if what is happening above (fewer losses) isn't so much that it found >winning moves for the opponent and sidestepped them, but that it found ways to >improve its position, even when worse, that the Neutral setting missed? Perhaps >its best defense isn't greater paranoia towards the opponent's chances, but >simply its superior evaluation. > > Albert If the idea fails, it will be because of an explanation like this. Certainly, a lot of chess tactics improve bad positions, or degrade good positions. The question is what is the most frequent, and to what extent. Search is basically a statistical thing, you want to search more promising things first. Vas
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