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Subject: Is position learning the key in shredder 7.04

Author: Rupesh

Date: 23:55:04 05/28/03


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).

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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