Author: Torstein Hall
Date: 04:19:43 05/29/03
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On May 29, 2003 at 02:55:04, Rupesh wrote: >Shredder 7.04 shows a curious behaviour. While playing on playchess, i have >observed that shredder's eval has a tendencey to change signs dramatically ( >like -2.4 from +1.3, many examples like this abound). While it is true that the >program does not show this kind of behaviour if the same position recurs again >and it does try a different move (perhaps using its learn file). > >So the program plays really badly initially and becomes better gradually after >playing a reasonably large number of games. I have a plr ( the learn file of >shredder 7.04) of 4.9 MB which is considered to be very big. Still shredder has >not stopped the habit of changine the sign of its eval. > >What i really suspect is that shredder's evaluation function is not robust and >often misses completely to evaluate a chess position at crucial time.I bneleive >this happens with shredder significantly more often than other programs. But >over repeated games against a fixed number of opponents ( it learns to expect >the kind of positions that might arise and becomes better)..but if it faces a >new opponent ( may be the same program on a different hardware and setting), it >again has to learn before it starts beating the opponent program.) > >It has been a curious fact that shredder starts doing well after playing many >games against a fixed opponent. I t almost always loses initial games against >any program ( mean inng any good program like f8, df7). I do not know Shredder very well, but I find it not very probable that the learn file should should affect play a lot. As there is quite a number of positions in chess and you would have to play a laaaarge amount of games to hit many learned positions during a game. But perhaps SMK has found a new way to generalise position learning, so the position only had to be similar and not 100% equal, but I doubt it. Torstein > >To my mind, it shows that shredder depends on learn file heavily. Which is >something which dissappoints me as i look for a program which has a good >evaluation function rather than learn function. > >Any remarks will be very muchg appreciated. > >Amitesh
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