Re: [eigen] New Licensing FAQ

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

2010/1/28 Daniel Stonier <d.stonier@xxxxxxxxx>:
> You've already got us on your web page (Yujin Robot), but as an aside,
> had an interesting development some 3-4months ago with regards to
> eigen.
>
> We were partnering with a much bigger company to develop a product and
> I've been using Eigen to drive the mathematics under the hood for
> quite some time when all of a sudden their legal team wanted to know
> all the specifics about what we're using.
>
> I've been careful about our code practices, making sure we never
> copy/paste/modify code and pushing for upstream changes when needed so
> we should never get in trouble, but Eigen turned into a veritable
> volcano within the space of a week. It was quite amusing watching
> events unfold. First email from their lawyers after we sent them a
> list of BSD/LGPL'd libraries we were using, and within the space of
> two sentences, (quoting) 'we will not support anything to do with
> those anti-patent fundamentalists.'

Wow, fun story!

Especially in our case, I'm pretty sure that we never even discussed
patents in our mailing list or anywhere --- anyway, Eigen being a
general mathematics library, it is essentially playing outside of the
domain where any patents exist, even in the US. I'm not aware of any
patented general linear algebra algorithm, and when that happens,
it'll be the last step until Pythagoras' theorem and the operation of
"multiplying two integers" ultimately get patented ;)

Notice one thing with respect copy and paste: the LGPL v3 is very
permissive with respect to #including code from header files. So if
you can implement your copy&paste as a #including operation, you
should be fine. As long as the LGPL code itself remains LGPL, there's
no worry. The only difference with BSD is when you are not including
LGPL code verbatim but are making changes to it: then the LGPL
requires you to release the modified source code, the BSD doesn't.

> And I found myself a little confused about exactly who was the
> fundamentalist... :P

Haha!

Just a question for my information. Were the lawyers in question from
the US or Korea?

> Anyway, turned out their legalese had adopted a blanket rule approach
> to LGPL3 in particular. The company had been in trouble with licensing
> before, mostly due to ignorance...and had adopted blanket policies
> that kept in line with their naivety.
>
> In the end, our project would have required a major overhaul and
> rescheduling at that point and our managers as well as theirs
> convinced their legalese that their poliical motivations towards GNU
> were not as important  as project schedules and budgets.

Nice to hear that pragmatism won!

>
> Anyway, Im happy say we're still enjoying eigen. My company even let
> me open up our control library which is starting to get some of the
> eigen stuff ported across to it (
> http://snorriheim.dnsdojo.com/redmine/wiki/ecl ).

Wow, this is really nice. So in the end, it sounds like your company
really 'got it'. This is the best licensing story I've heard in a
while! It's a great example that I'll keep in mind of why it's good
that we keep with the LGPL in the absence of any user having a
concrete legitimate need (as opposed to a 'political need') for
something even more permissive.

> Oh, and we're also using it in tandem with RoS as we start to plan our
> new platforms.

Great!

>
> Congratulations on the job by the way!

Thanks!

>
> Regards,
> Daniel Stonier.
>
> PS: I suspect some companies may be hesitant to use LGPLV3's as it has
> not been out in the wild for too long yet. Especially the older, more
> conservative companies who are missing the boat and concept behind
> open source and are still clinging to old paranoia's.

Good to know, and sounds like good news as this should naturally
improve over time.

Benoit