[SciPy-User] log pdf, cdf, etc

[Nathaniel Smith]

On Fri, May 28, 2010 at 9:00 PM,  <josef.pktd at gmail.com> wrote:
> On Fri, May 28, 2010 at 11:24 PM, Nathaniel Smith <njs at pobox.com> wrote:
>> On Fri, May 28, 2010 at 7:53 PM,  <josef.pktd at gmail.com> wrote:
>>> R's license, GPL, is incompatible with the license of scipy, BSD.
>>> While they are allowed to look at our code, code that goes into scipy
>>> cannot be based on GPL licensed code.
>>
>> You mean, they're allowed to copy our code, and we're allowed to look
>> at their code for reference but can't use it directly :-).
>
> We are allowed to look at their manuals but not their code.
> (Life ain't fair.)

It sounds like you guys have this well in hand, but just a point here
-- you certainly are allowed to look at their code, just not copy the
"expressive aspects" of it. (Saying you can't *look* at it because of
the license is like saying writers can't read other people's novels!)
"Expressive" is a tricky term, of course -- IIUC it's basically
anything that could be changed while preserving functionality (because
the functionality, the algorithm itself, is not covered by copyright).
So, say, variable names certainly count as expressive, decisions about
which way to lay out the code, etc. If one wants to be really safe,
one can write down a textual description of the algorithm and then ask
someone else to translate back to code (the "clean room" method).

So you do have to be a bit careful, but when you have code that
contains valuable information that isn't really written down anywhere
else then I'd say it's worth it.

-- Nathaniel