There have been rumblings for years, at least since Strelka came out. I happen to think the GPLed code of Fruit was the best thing to happen to computer chess for a long while (thank you to Fabian). IMHO, cloning is not a bad thing since allows incremental improvement by multiple authors. Cloning without respecting the license of the source, however, it not okay and it seems clear now that's what Rajlich did.
For those interested in the issue, I recommend you read the report, as well.
Some real heavies weight in on the issue including Ken Thompson. All are in agreement that early versions of Rybka show disturbing similarities to Crafty and then Fruit(this is when the big jump in rating performance was made).
Rajlich has continued to claim that his code is all original which is highly doubtful.
To me the real damning evidence was by Hyatt, which showed that the early version of Rybka has whole bunch of useless code from Crafty, which Hyatt had used:
"Summary: Pre-Rybka 1.6.1 contains much identical code to Crafty, even including large
blocks of code with obsolete code inside them, and code that performs tests that make
no sense today (code that was left in Crafty by accident, by Robert Hyatt, also shows
up in Rybka 1.6.1)."
Off course, most of the code must be gone by the later versions, but it is seriously in such a bad taste to be so disrespectful to other programmers.
Comments
There have been rumblings for years, at least since Strelka came out. I happen to think the GPLed code of Fruit was the best thing to happen to computer chess for a long while (thank you to Fabian). IMHO, cloning is not a bad thing since allows incremental improvement by multiple authors. Cloning without respecting the license of the source, however, it not okay and it seems clear now that's what Rajlich did.
Thank you for the explanation!
I took the time to read the official report on Rybka Investigation and Summary of Findings for the ICGA http://www.chessvibes.com/plaatjes/rybkaevidence/RybkaInvest...
For those interested in the issue, I recommend you read the report, as well.
Some real heavies weight in on the issue including Ken Thompson. All are in agreement that early versions of Rybka show disturbing similarities to Crafty and then Fruit(this is when the big jump in rating performance was made).
Rajlich has continued to claim that his code is all original which is highly doubtful.
To me the real damning evidence was by Hyatt, which showed that the early version of Rybka has whole bunch of useless code from Crafty, which Hyatt had used:
"Summary: Pre-Rybka 1.6.1 contains much identical code to Crafty, even including large blocks of code with obsolete code inside them, and code that performs tests that make no sense today (code that was left in Crafty by accident, by Robert Hyatt, also shows up in Rybka 1.6.1)."
Off course, most of the code must be gone by the later versions, but it is seriously in such a bad taste to be so disrespectful to other programmers.