Re: matlab2tikz and dual BSD/GPL licensing

[bpabbott]

On Dec 14, 2010, at 10:26 PM, Judd Storrs <address@hidden> wrote:

On Tue, Dec 14, 2010 at 9:27 PM, Ben Abbott <address@hidden> wrote:
> The project matlab2tikz is now able to handle surface plots.
>
>        http://win.ua.ac.be/~nschloe/content/matlab2tikz-v006-released-initial-support-surface-plots
>
> I've contacted the author about using a GPL based or compatible office. Currently he (Nico) has adopted the BSD license promoted by MathWorks, but likes the idea of licensing under GPL.
>
> Is it possible to license both under BSD and GPL? ... and how might that be done?

It is possible to dual license this way.

On the other hand, it seems somewhat silly because the 3-clause BSD
license is GPLv2 and GPLv3 compatible. The issue is when a contributor
insists on GPL-only for their patches. Nico needs to be very clear
about how he will treat such contributions. BSD/GPL dual-licensed
files can lead to discord:

http://kerneltrap.org/Linux/Continuing_Dual-Licensing_Discussions
http://www.linux-watch.com/news/NS2902106404.html

Personally, it seems to me that the presence of the BSD license option
defeats the GPL. It really depends on whether Nico wants to possibly
maintain two branches. Perhaps one branch containing GPL-only
enhancements hosted on octave-forge with components that cannot be
used in the BSD-licensed branch, and a separate branch that is GPL/BSD
dual-licensed branch.

The other alternative is to license GPL-only -- but of course he would
have to forgo MatlabCentral hosting in that case. As far as I know
GPL-licensed packages can be used in Matlab, Mathworks just won't host
them.

--judd

Thanks for the links. 

The BSD license promoted by Mathworks is a 2-clause variant of the BSD license.

While reading the links, I was reminded that GNU has a page discussing various licenses. The part on the 3-clause BSD is linked to below.

http://www.gnu.org/licenses/license-list.html#ModifiedBSD

The 2-clause is the same as the 3-clause with the third clause removed.

"3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission."

I also came across the article "Maintaining Permissive-Licensed Files in a GPL-Licensed Project: Guidelines for Developers". The part I think is appropriate to this discussion is section 2.3 (Keeping modified files permissive-licensed within larger GPL’d works).

http://www.softwarefreedom.org/resources/2007/gpl-non-gpl-collaboration.html

In this instance, my understanding is that the GPL is more restrictive than the BSD license. Meaning that there may be a problem with propagating patches from a GPL branch to a BSD branch ... which I assume is what Judd was referring to when he wrote

The issue is when a contributor
insists on GPL-only for their patches. Nico needs to be very clear
about how he will treat such contributions

My impression is that if a pkg for matlab2tikz were included in Octave Forge, the problems would be minimal (is it permissible to use the BSD license on Octave-Forge?). If we decided to include a derivative of this function in Octave's core then I think we'd want to branch the development. I don't think this would be a big deal since the coding standards for Octave would require a rewrite anyway (only minor changes are needed to run matlab2tikz).

Personally, I'd like to add this function to Octave's core. This would allow for consistent TikZ output for the gnuplot and OpenGL backends. If that were done, the Octave version would be GPLv3 and would include Nico's name as author and copyright holder. The maintenance and development could then continue under Octave.

Ben