[SciPy-User] fit with 3 parameters ok, fit with 4 is going wrong!

[Robert Kern]

On Fri, Feb 7, 2014 at 9:42 PM, Matt Newville
<newville at cars.uchicago.edu> wrote:
>
> On Fri, Feb 7, 2014 at 7:22 AM, Robert Kern <robert.kern at gmail.com> wrote:
>>
>> On Fri, Feb 7, 2014 at 1:03 PM, Matt Newville
>> <newville at cars.uchicago.edu> wrote:
>> >
>> > On Feb 6, 2014 5:14 PM, "Robert Kern" <robert.kern at gmail.com> wrote:
>> >>
>> >> On Thu, Feb 6, 2014 at 9:20 PM, Matt Newville
>> >> <newville at cars.uchicago.edu> wrote:
>> >> > Hi David,
>> >> >
>> >> >
>> >> > On Thu, Feb 6, 2014 at 2:20 PM, Daπid <davidmenhur at gmail.com> wrote:
>> >> >>
>> >> >> On 6 February 2014 18:55, Matt Newville <newville at cars.uchicago.edu>
>> >> >> wrote:
>> >> >>>
>> >> >>> I'm interested, but slightly confused.   Iminuit / probfit is
>> >> >>> described
>> >> >>> as BSD, but depends on (and includes?) Minuit - isn't that GPL?
>> >> >>
>> >> >>
>> >> >> The license says iminuit is MIT, but Minuit is GPLv2. So, the Python
>> >> >> part,
>> >> >> that wraps the C code is MIT.
>> >> >
>> >> > The way I understand it, code that wraps GPLv2 code is required to
>> >> > use
>> >> > GPL,
>> >> > and so propagate the license to all code using it. That would mean
>> >> > that
>> >> > code
>> >> > that uses Minuit cannot be something other than GPL.   Perhaps I am
>> >> > not
>> >> > understanding something.
>> >>
>> >> GPLed code can be combined with code under a different license as long
>> >> as that other license imposes no conditions more restrictive than
>> >> those in the GPL. The MIT license is one such license. This is all
>> >> perfectly above board.
>> >
>> > Unless I am mistaken (not without precedent), the resulting mixed code
>> > must
>> > use the GPL. If library "M" is GPL and package "Mwrapper" calls it,
>> > "Mwrapper" must be GPL.   This license propagation is the distinguishing
>> > characteristic of GPL, and what differentiates it from LGPL and BSD/MIT.
>> > Do
>> > you disagree?
>>
>> Yes. The combined work must be distributed under the GPL license. But
>> each component can have a non-GPL-but-GPL-compatible license, like the
>> MIT license. The parts of "Mwrapper" that are not "M" itself do not
>> need to be GPLed. "Mwrapper+M" is GPLed. "Mwrapper" itself does not
>> need to be (provided they are licensed compatibly).
>>
>
> The parts of Mwrapper that use M must be GPL.
>
>>
>> This is why I say that the *practical effect* of saying that
>> "Mwrapper" is BSD-licensed is confusing. Users grab "Mwrapper+M" under
>> the impression that "Mwrapper"'s license is the only one, when it is
>> not.
>>
>> >> That said, as a practical matter, for a package that mostly just wraps
>> >> the functionality of the internal GPLed component, licensing that
>> >> wrapper under the MIT license leads to confusion, as we have seen.
>> >
>> > I think this does not lead to confusion, but to a license violation.
>> > The
>> > GPL is wordy, but not confusing.  If your code wraps (uses, links to,
>> > imports, or calls) GPL code, your code must use the GPL.  Not MIT.
>>
>> You have misread the GPL. Please consult the FSF's information about
>> mixing code with GPL-compatible licenses. The propagation applies to
>> the combined work as a whole, not every single piece of code in the
>> combined work.
>
> Perhaps this is a bit off-topic, but I believe that I have not misread the
> GPL. I do agree that it does not apply to every single piece of code in the
> combined work.  But I believe (and, sorry but I am not convinced by you
> saying otherwise, without strong evidence) it does apply to every piece of
> code that **uses** the GPL code, including making library calls.

Section 7 of the GPLv3:

"""
You may place additional permissions on material, added by you to a
covered work, for which you have or can give appropriate copyright
permission.
"""

Applying the BSD license to the portions of the code that you wrote is
providing just such additional permissions.

-- 
Robert Kern