Author: Christophe Theron
Date: 20:06:56 12/10/00
Go up one level in this thread
On December 10, 2000 at 17:33:14, Thorsten Czub wrote:
(snip)
>The draw-score moves: 29,30,31,32,33,34,35,37,38,39,40,41 shows exactly the area
>Gambit-tiger gets the evaluation increase.
>In the moments Gambit-Tiger SEES and idea and evaluates it, Fritz sees only
>Silly draw-scores or scores nearly sero.
You are much too harsh against Fritz, Thorsten. Actually against Frans.
I don't see drawing score in difficult positions as a charateristic of Fritz,
even in your example.
It is apparently simply a by-product of a choice made by the programmer. The
programmer thinks that his program can see deep enough in most of the cases, and
that it will see by search when a king attack is overwhelming.
So if the search does not say "it works", the programmer's choice is to give a
rather low weight to the king attack.
That's why, if the search does not say that the attack will succeed, the program
can believe that the weaker side (based on material and other positional terms)
will try to get a draw. Even if actually the "weaker" side has a "strong" king
attack.
And it's a fact that the side that has a strong attack can generally force a
draw if it wants to. And generally, forcing the win takes much more plies, so
only the draw can be foreseen in a reasonnable time by search.
That's all you can say about this behaviour. I don't think it's something
written in stone in the Fritz engine. It's only because the programmer's choice
is to rely more on search than on evaluation to detect strong king attacks.
Now you can disagree, as I do, with this choice. However I can understand it,
because until version 12.0, Chess Tiger was doing the same. And not taking care
of king attacks is much, much simpler in term of programming efforts.
Now I have changed my mind, and the best proof is Gambit Tiger. But my task is
huge. Correct evaluation of king attacks is extremely difficult (solve this and
you are close to solving chess).
Fritz maybe underestimates the king attacks. As Genius and many others do. That
gives them an incredible steel-nerves style. When it works, they seems to play
like ET. And when it fails it makes them look very stupid.
Gambit Tiger has another approach and takes care of king attacks. It gives it an
interesting attacking style. When it works, it seems to play like a real GM. But
when it fails, it looks as stupid as the programs of the other group.
I don't see the draw score behaviour like an intrinsic weakness of Fritz. It's a
choice, a pragmatic choice, call it a bet, that has been working for years in
computer chess. We will see if it will keep on working in the next years, but
that's another story...
Christophe
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