[SciPy-dev] PRIMME: PReconditioned Iterative MultiMethod Eigensolver

Robert Kern robert.kern at gmail.com
Sat Oct 28 04:33:35 CDT 2006

Gary Ruben wrote:
> Robert Kern wrote:
>> Gary Ruben wrote:
>>> Hi Brian,
>>> The issue is not one of convenience. The issue is that the GPL and LGPL 
>>> are legally and practically incompatible with the scipy/MIT licence and 
>>> would require a change of the scipy licence is any of their code were to 
>>> be included with the existing package.
>> No, it wouldn't. scipy's license is compatible with the GPL in that one can 
>> combine scipy code and GPLed code just fine without relicensing anything. The 
>> scipy license grants strictly more freedoms than the GPL.
>> However, the longstanding *policy* of the scipy project is not to include code 
>> with more restrictions than the BSD license. There are some exceptions made for 
>> certain wrappers which are strictly optional like FFTW.
> Sorry. Thanks for the correction. Would it be more correct to say that 
> there might be the possibility that, were Scipy to be incorporated in 
> commercial software, the existence of GPLed parts might cause confusion 
> on the part of developers? Is this the reason for the policy?

It's more than a possibility; it *is* incorporated in all of Enthought's 
proprietary software. As long as scipy is still a monolithic package with 
interdependencies between its components, introducing a non-optional GPLed 
component does more than cause confusion; it makes scipy impossible for us and 
others to use in this manner. The LGPL does not cause the same issue; however, 
we've always favored keeping scipy as a whole BSD-licensed for a number of 
reasons. The Python community tends towards BSD-like licenses due to Python's 
license; BSD-like licenses are easier to explain to our customers; it's 
requirements are easier to explain to other programmers. At this point in time, 
introducing an LGPLed component is most likely to cause confusion amongst the 
other BSDish components, as you say.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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