Anthony Cozzie about Rybka

[Sylwy]

"In hindsight, Vasik must have been quite amused
by those discussions, because Rybka's "secret" was simply to be super
optimized to 3 or 4 times faster than everything else."

Take a look to :

http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=3172

Regards,
Sylwy

[Tony Thomas]

Only post that I found interesting.

I have to thank you for your post, because it exposes a completely
different viewpoint than my own, and yours is probably much more
common. One of the interesting things about computer chess is that it
is both a scientific and competitive endeavour. As a graduate
student, I am emphasizing the former. As a user and computer chess
enthusiast, you are emphasizing the latter.

In academia, novelty rules all. It is much better to be novel than to
have great experimental results. The goal is to add to the knowledge
of the human race, and the key question is "What can we as a community
learn from this?" You will have to take my word for it that the
source code of Strelka simply does not contribute to the state of the
art in building computer chess engines. Consider Fruit: you can take
the new ideas from Fruit, add them to an existing chess program, and
make it better. Just about everyone uses late move reductions of some
sort nowadays. There is no equivalent in Strelka, no magical
techniques that could be added to a new chess program and give it 100
elo. There is no equivalent to null move, history pruning, or even
singular extensions. For two years, whenever things were becoming
boring computer chess enthusiasts could always debate about what
Rybka's secret was. In hindsight, Vasik must have been quite amused
by those discussions, because Rybka's "secret" was simply to be super
optimized to 3 or 4 times faster than everything else.

There is only one thing that is really interesting about Strelka: that
a search is still important. A lot of people (myself included, under
the dark school of Diepeveen) thought that 16-18 or at most 20 ply was
sufficient for any position. Obviously, we were wrong. This is why I
said earlier that I thought Vasik went in a different direction (at
least from me). While I was trying to improve the evaluation, he was
trying to optimize his program, and since Rybka gets about 4-5 more
plies than Zappa, his 5 ply search, especially in quicker games,
proved better than my heuristical evaluation.

Anyway, from an engineering standpoint Strelka (rybka) is fantastic.
It packs most of the search and evaluation of Fruit/Crafty into
something almost 3 times faster. For those of you that have never
written code, 3 times is quite a bit, considering that Fruit and
Crafty are already reasonably well coded. Rybka is even faster than
the ultimate beancounter, Fritz 5, while having a lot more under the
hood. And this is why I said that Strelka was more a source of
motivation than insight, because I had never really taken the time to
optimize Zappa, persuaded by the standard CS doctrine of "don't waste
your time trying to improve the constants on an exp-time algorithm".

What this all boils down to is the difference between interesting and
useful, two qualities that are often unrelated.

I think that is about the best I can do to try to explain my
viewpoint. I personally have had a life long love affair with science
and engineering. I find it amazing that they work at all. Imagine
the zillions of quantum interactions involved when we say that the
American dollar has lost value against the Euro! That we can build
models for such complex phenomena is preposterous - and yet those
models work down to 20 decimal places. This is why I am trying to
earn my PhD: I would like to make some small contribution to science.
Of course, I don't expect everyone to have this view. I don't think
this particularly bothers Rajlich; he seems a pure competitor who wants
to win games and keep himself in twinkies. Just because it isn't
scientifically interesting
(or wasn't in 2005. Perhaps he has done something interesting
since then) doesn't make Rybka any less of a great chess program.

cheers,

anthony

P.S. I don't consider Zappa to be particularly interesting from a
scientific standpoint either. This is why I don't work on it that
much.

P.P.S. I think this scientific attitude is what gets Hyatt in trouble in this forum as well.

P.P.P.S. Yes, I am sort of arrogant. We all have these little flaws, but it is considered courteous not to point them out.