Witam, i am aware that at least one person felt that an earlier version of a package i released contained "expressions (particularly any arbitrary or stylistic choices)" identical to those in Numerical Recipes routines.
My own judgment had been that the expression was different, only the "ideas, methodology and algorithm" were identical to the Numerical Recipes routines. In NR's own words, this is perfectly acceptable within the definition of copyright. And, of course, there were clear warnings that the code was inspired from NR.
Nevertheless, i followed the concern, and stopped distribution.
In order to avoid any ambiguity, i (and any other volunteers) will rework the code using routines from the GSL (GNU Scientific Library):
http://adjani.astro.uni.torun.pl/cgi-bin/twiki/view/Cosmo/ComputerLanguages#...
which Michał Frąckowiak brought to our attention :)) and will reexpress any remaining algorithms, possibly changing the algorithms themselves, even though this is not necessary.
However, you might want to note that there seems to be something curious about a certain non-free package called Healpix_1.20.
i suggest to people with a copy of this package to have a look at two files, which, apparently, exist in this package:
Healpix_1.20/src/f90/mod/num_rec.f90
and also at the copyright notice Healpix_1.20/READ_Copyrights_Licenses.txt
and then to look at the Numerical Recipes guidelines for redistributing their routines, whether binary or as source code:
http://www.numerical-recipes.com/com/info-permissions.html
Apparently, the file Healpix_1.20/src/f90/mod/num_rec.f90 contains the source code for the routines:
dsvbksb dpythag dsvdcmp isort
A quick search on google on, e.g., "dsvbksb" shows that NR probably cannot control distribution of these files:
http://www.google.pl/search?hl=pl&q=dsvbksb&btnG=Szukaj+z+Google&...
Nevertheless, there *are*, apparently, NR routines provided as source code in the file Healpix_1.20/src/f90/mod/num_rec.f90 which is *claimed* to be NR code, including one-line copyright notices from NR.
In principle, redistributing NR routines without permission from NR is a violation of copyright - stating the copyright notice is not enough to satisfy NR.
Of course, it could, in principle, be the case that the Healpix collaboration have paid "a fixed fee" for this and have permission to redistribute.
However, first note the cases in which NR provides permission: http://www.numerical-recipes.com/com/info-permissions.html
if you want to make available to your users a subset of Recipes in object, or individually callable, form, but not including source code. We consider such requests on a case-by-case basis, with permission more likely when they are for fewer than 20 Recipes used in this manner.
- In most cases of specialized software, we charge only a nominal
flat fee per Recipe for each use (unlimited number of copies).
- The copyright notice is required, as above, and we also request that
the printed manual contain words to the effect "the procedures [your procedure identifiers] are based on routines in Numerical Recipes: The Art of Scientific Computing, published by Cambridge University Press, and are used by permission."
Note: "not including source code".
Also: the full copyright notice (not just one line, see "EXACT WORDING OF REQUIRED COPYRIGHT NOTICES" on http://www.numerical-recipes.com/com/info-permissions.html ) is required.
However, for distributing *source code*:
Finally, there is the case where our source code, or source code based in copyright on our code, is to be made available to users. We consider these requests on a case-by-case basis, but the success rate of these requests is not high.
...
# If permission is given, you will need to include a notice similar to the sample below as a comment in each routine that is based on a Numerical Recipes routine.
So Healpix_1.20 could, in principle, redistribute NR source code (probably for a fixed fee).
However, this is only considered "on a case-by-case basis" and "the success rate of these requests is not high".
Moreover, there would need to be the full copyright notice, and, apparently, the file Healpix_1.20/READ_Copyrights_Licenses.txt does not contain any reference to Numerical Recipes.
Also, the full copyright notice needs to be included "as a comment in each routine". (GNU recommends including a big copyright announcement at the top of each routine, not just one line.)
There could be one way around this: since Healpix is non-free, and requires personal email between applicants and authors, the authors could restrict distribution to people who declare that they already have access to a legal copy of NR. i'm not sure if NR would be happy, but it might work.
However, this is not our problem. But it does demonstrate why an open model of code development has advantages: people worried about copyright issues are more likely to speak up earlier in an open model compared to a non-free model. Now that Healpix is so widely used, the authors might have a problem negotiating with NR based on the large number of copies already distributed.
It would seem to me that their options are either to negotiate with NR and pay whatever fee is required (i'm sure ESO could pay this), or else to rewrite the parts that need NR recipes.
Of course, that is their problem, not ours.
pozdr boud
PS: It would also seem that Healpix has been using Mahatma Gandhi's "illegal civil disobedience" technique in protest against the patent on the LZW compression algorithm for making gif files. This file Healpix_1.20/src/f90/lib/gd.c apparently contains the ppmtogif.c code
The code itself is freely redistributable. However, *usage* of the code was probably illegal, since the *algorithm* was patented. This is different from copyright, which only protects the expression of an algorithm and not the algorithm itself. See
http://netpbm.sourceforge.net/doc/ppmtogif.html
If you use ppmtogif without the -nolzw option, you are using a patent on the LZW compression method which is owned by Unisys, and in all probability you do not have a license from Unisys to do so. Unisys typically asks $5000 for a license for trivial use of the patent. Unisys has never enforced the patent against trivial users. The patent expired in the US in 2003 and is due to expire in other countries in 2004.
So the patent has now expired (e.g. http://news.bbc.co.uk/1/hi/technology/3007862.stm ) but for many years, more "conservative" GNU/Linux groups like GNU, Debian recommended using PNG instead of GIF, or else used a pseudo-GIF format.
More radical software groups and probably millions and millions of users (probably including you!) simply used the algorithm despite the patent.
A big battle is continuing against software patents in Europe.
Go to http://kwiki.ffii.org/SwpatplEn to see info on what Polish poseł in the European parliament are doing or http://kwiki.ffii.org/FfiiprojEn or http://www.gnu.org/server/takeaction.pl.html for more on what you can do concretely.