On Sat, Dec 13, 2008 at 3:32 PM, Benoit Jacob
<jacob.benoit.1@xxxxxxxxx> wrote:
2008/12/14 FMDSPAM <fmdspam@xxxxxxxxx>:
> I have read your emails beforehand :-) . Yes Eigen2 is really amazing and
> seems to me very agile.
> My focus are the sparse linear algebra for FEA-like stuff at first But I am
> really impressed of the wide range of performance gifts, eigen2 is able to
> spent. I really like the idea to only deal with one lib in a consistent
> design for all my linear algebra.
If you're mostly interested in the Sparse module, note that it's still
considered experimental, although it is probably going to become
stable (i.e. API stability guaranteed) in about 6 monthes as Gael is
currently working on potentially making KDE 4.3 rely on it.
> For me, legal issues are always somewhat like quirky nitpicking. So, I am
> sorry for my quirks contribution here, really.
Np, actually my main concern regarding licensing is to allow everybody
to use Eigen just so we don't have to deal with any licensing issues.
That's how I meant the LGPL when I chose it.
If you ever find that the LGPL doesn't allow you to use Eigen then
tell us and we'll consider relicensing.
If it turns out that the BSD does provide the same back-contribution
guarantee in our case, then why not add it as a license choice (so
we'd triple-license).
There is no back-contribution requirement in the BSD license. The BSD license is one of the easiest to read:
http://en.wikipedia.org/wiki/BSD_license
The nicest part of a BSD license is that it's easy for companies to approve usage. With higher uptake in commercial products, hopefully more developers will use Eigen, and contributions will flow back. However, there is no requirement for contributions.
It's a tough call which is better for a core numerical library such as Eigen (bsd vs lgpl). There are arguments on both sides. Some companies are GPL-phobic, even LGPL, so it is not unimaginable that an eigen developer might end up not being able to use eigen at work. However there is a higher chance to fork with the BSD license. For my project, libmv, I chose the MIT license because I wanted to encourage companies to use it and improve it because there are a limited number of free software hackers that are also computer vision experts. I am willing to take the chance that some companies will use the software without releasing their contributions. With Eigen, the situation is a bit different because of the wide appeal.
Keir
Cheers,
Benoit
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