[Numpy-discussion] Code for compatibility with gfortran, license issues

[Bruce Southey]

On 06/29/2009 12:15 PM, Robert Kern wrote:
> On Mon, Jun 29, 2009 at 00:34, David
> Cournapeau<david at ar.media.kyoto-u.ac.jp>  wrote:
>    
>> Hi,
>>
>>     I started working on a new approach for windows 64 bits support, to
>> be able to combine gfortran and visual studio. Basically, I am
>> reimplementing the needed functions from libgfortran so that it can be
>> built with MS compiler, but I cannot hope to do that without using
>> gfortran sources (under the GPL 3), if only for the signature/API of the
>> functions.
>>      
>
> Function signatures and public APIs are not copyrightable. What else
> do you need?
>
>    
>> Is it ok to include those sources in numpy/scipy, given that
>> they will only be used in those cases where libgfortran would have to be
>> used anyway ?
>>      
>
> Keep in mind that libgfortran is GPLv3+exception. Is the code that you
> are looking at from gfortran itself (GPLv3) or libgfortran
> (GPLv3+exception)?
>
>    
Since you appear to require that the user already has gfortran 
installed, then you just need to avoid adding any GPL licensed code to 
actual numpy/scipy code as that would make numpy/scipy GPL. See SFLC's 
'Maintaining Permissive-Licensed Files in a GPL-Licensed Project: 
Guidelines for Developers':
http://www.softwarefreedom.org/resources/2007/gpl-non-gpl-collaboration.html

I would think that you could just provide an appropriately licensed 
package that combines a separately downloaded numpy/scipy with the  
separately downloaded/installed gfortran to install the new version of 
numpy/scipy. Essentially the same way you get non-free software like mp3 
decoders for certain Linux distros. If that works, then perhaps a clean 
room implementation and rewrite of certain fortran code could be done to 
remove the gfortran dependencies.

Regards
Bruce



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