[GiNaC-list] sympy and a derived work

[Richard B. Kreckel]

Dear Ondrej,

Ondrej Certik wrote:
> I was recently at a Sage workshop, some of my notes here:
> 
> http://ondrejcertik.blogspot.com/2007/11/sage-days-6.html
> 
> and there we also discussed sympy and ginac and licensing issues
> and we came to the conclusion, that just by copying a C++ code
> to Python (by hand) is a derived work. That's what I did
> at the beginning - I used the same class structure and copied
> some of the algorithms from ginac. Ginac is GPL and sympy used to be too,
> so far so good. But then, we decided to use BSD, because
> it's more free and we think it's just better for sympy.

Good heavens. Let's not try to quantify this "free" thing too much, 
please. At the ICMS'2006 in Spain, someone started exactly the same 
discussion at the end of my talk about CLN: Some people really do 
believe that if you put your software under a BSD, LGPL, or MIT style 
license, then the entire closed-source software industry will 
miraculously be turned into saints and start helping your project by 
contributing code, doing the debugging for you, organizing events, 
giving you free lunch, etc.

That is just so naive. At the ICMS'2006, the GMP (LGPL) developer 
explained in response, how much feedback he ever got back from Wolfram 
Research who ship libgmp with Mathematica: absolutely no feedback. Zero, 
vacuum, null, rien, nada, nix. There was a Wolfram employee in the room 
then, and I don't really know if the situation has changed since but I 
wouldn't bet it has.

Oh, and interestingly, at the end of the old argument why CLisp is GPL 
you'll find someone foreseeing this problem with GMP:
<http://cl-debian.alioth.debian.org/repository/pvaneynd/bzr-moved/clisp/doc/Why-CLISP-is-under-GPL> 
(CLN wasn't around at that time. But it borrows enough code from CLisp 
so that this argument applies to it, too. In the end, it's not 
far-fetched to argue that this decision set the course for GiNaC's license.)

If you pick another license, that's fine. But, please, be careful not to 
offend other open-source developers who, by choice or by necessity, made 
a different pick.

> However, we now changed almost everything in sympy,
> just the class structure stayed - but I mean - it's just a class structure
> (even that is not 100% the same, we don't use ex for example).
> 
> So I wanted to clarify with you, if it's ok, if we use BSD for sympy.

Ondrej, you're going to have fun if you are seriously bringing this up.

IANAL, but you are obviously raising two questions: Is SymPy derived 
work of GiNaC? Personally, I do not know or care (but don't know about 
other contributor.) If *you* think it is, then, you must now clarify the 
situation with the copyright holder for GiNaC. According to the source 
files, that would be the University of Mainz, Germany. Please, do keep 
us posted about what comes out from the discussion with their lawyers, 
okay? Because I don't think they are reading this list.  ;-)

Best wishes
    -richy.
-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>