Strelka -- Open source

[Orlov]

Why we don't attack rybka. Well known that Strelka is rewriten fruit and also well known from rybka forum that Strelka = Rybka 1.0 beta. What happens? Double standarts?

[hgm]

The difference is that Fruit was puplished as open source, which obviously has the intention that others might learn from how it works. With Rybka, this might not have been the case, as not many people possess the skill to decompile and decipher such a complicated piece of software.

Of course it is rather common practice that commercial competitors put each others products under the microscope. I would be really surprised if most commercial programmers would not have at least made an attempt to take a peek at the Rybka 'secrets'.

[Uri Blass]

Why we don't attack rybka. Well known that Strelka is rewriten fruit and also well known from rybka forum that Strelka = Rybka 1.0 beta. What happens? Double standarts?

It is not well known that strelka is rewritten fruit.

I have both sources and I say that strelka is not a clone of fruit.
Strelka takes some ideas from fruit is not using code of fruit and is allowed.

Uri

[Uri Blass]

The difference is that Fruit was puplished as open source, which obviously has the intention that others might learn from how it works. With Rybka, this might not have been the case, as not many people possess the skill to decompile and decipher such a complicated piece of software.

Of course it is rather common practice that commercial competitors put each others products under the microscope. I would be really surprised if most commercial programmers would not have at least made an attempt to take a peek at the Rybka 'secrets'.

I think that this type of effort is not the most productive way to try to get a strong program.

I have problems to understand programs that came with source so trying to decompile programs without source is probably a bad idea because the programmer may get more progress by trying to understand existing strong source programs.

Uri

[Orlov]

Igor Korshunov very good know strelka's code. His opinion - Strelka is rewriten Fruit. I don't ask that strelka is clone.

[Alexander Schmidt]

Why we don't attack rybka. Double standarts?

No. There is no evidence that Rybka took code from Fruit. There are strange similaries between Rybka and Fruit, and I posted this in CCC when Rybka 1 came out.

Alex

[hgm]

Well, re-writing Fruit is not forbidden. Copying and modifying it is only forbidden if you are not prepared to publish your sources under GPL.

If we would want an algorithmically identical re-write, or a port to another high-level language, or a PGO re-compile of an engine to compete in our tournaments as a separate entry is of course a different matter. If someone merely re-writes the search of Fruit, but completely changes the evaluation, this becomes an even more difficult decision.

[Orlov]

What your opinion: Strelka is clone Rybka 1.0 beta?
Happy New Year!

[Orlov]

If I take your moves generator, take eval from fruit, and take search from Glaurung It russian salad will be not a clone?
Happy New Year!

[Uri Blass]

Igor Korshunov very good know strelka's code. His opinion - Strelka is rewriten Fruit. I don't ask that strelka is clone.

I am not sure what means rewritten but it seems clear that no copy and paste from fruit was done.

I cannot take significant part of strelka and say that this is part of fruit except variable names.

Uri