Mark,

thank you for pointing out an important point that I did not though about.
However, in that case the problem does not happen since the code is
already GPL (see https://github.com/MathieuDutSik/DualDescriptionADM)

I use GLPK for solving linear program in algebraic computation. When
GLPK approximate solution give exact solution, it does in very short time.
Otherwise I use the much slower cddlib from above github repo but this
is rare.

  Mathieu

On 14 December 2016 at 18:22, Meketon, Marc <[email protected]>
wrote:

> I am, by no means, the expert on the GPL license that GLPK.  My
> understanding is that if you make the changes suggested below and then
> proceed to distribute the software publicly (outside of your company), you
> will need to make the modified source code available to the users.  The
> actual wording is below.
>
>
>
> That’s one of the reasons why I prefer using Option (A) – no modification
> is required, so less burden on me if I give away the application.
>
>
>
> [below is from https://www.gnu.org/licenses/gpl.html]
>
> *5. Conveying Modified Source Versions.*
>
>
>
> You may convey a work based on the Program, or the modifications to
> produce it from the Program, in the form of source code under the terms of
> section 4, provided that you also meet all of these conditions:
>
>
>
> a)      The work must carry prominent notices stating that you modified
> it, and giving a relevant date.
>
> b)      The work must carry prominent notices stating that it is released
> under this License and any conditions added under section 7. This
> requirement modifies the requirement in section 4 to “keep intact all
> notices”.
>
> c)       You must license the entire work, as a whole, under this License
> to anyone who comes into possession of a copy. This License will therefore
> apply, along with any applicable section 7 additional terms, to the whole
> of the work, and all its parts, regardless of how they are packaged. This
> License gives no permission to license the work in any other way, but it
> does not invalidate such permission if you have separately received it.
>
> d)      If the work has interactive user interfaces, each must display
> Appropriate Legal Notices; however, if the Program has interactive
> interfaces that do not display Appropriate Legal Notices, your work need
> not make them do so.
>
>
>
> A compilation of a covered work with other separate and independent works,
> which are not by their nature extensions of the covered work, and which are
> not combined with it such as to form a larger program, in or on a volume of
> a storage or distribution medium, is called an “aggregate” if the
> compilation and its resulting copyright are not used to limit the access or
> legal rights of the compilation's users beyond what the individual works
> permit. Inclusion of a covered work in an aggregate does not cause this
> License to apply to the other parts of the aggregate.
>
>
>
> -----Original Message-----
> From: Help-glpk [mailto:help-glpk-bounces+marc.meketon=oliverwyman.com@
> gnu.org] On Behalf Of Andrew Makhorin
> Sent: Wednesday, December 14, 2016 11:27 AM
> To: Mathieu Dutour
> Cc: [email protected]
> Subject: Re: [Help-glpk] Parallel runs of glpk
>
>
>
> On Wed, 2016-12-14 at 15:06 +0100, Mathieu Dutour wrote:
>
> > I am interested in running glpk from a multithreaded program.
>
> > The goal is not to have GLPK itself parallel but instead to have glpk
>
> > used many times by different threads for solving many different linear
>
> > programs.
>
> >
>
> >
>
> > As is well known glpk is not thread safe and my question is about
>
> > alternative solution to that problem. Here are some
>
> > possibilities:
>
> >
>
> >
>
> > A) One is to have to run glpsol standalone by running it as external
>
> > program with the input file generated by the thread and then read by
>
> > the thread. But this solution has its costs in terms of runtime. It is
>
> > easy to program.
>
> >
>
> >
>
> > B) Have one thread that does only call glpk. It is adequate in single
>
> > threaded performance but potentially expensive since some thread may
>
> > wait. Relatively easy to program.
>
> >
>
> >
>
> > C) Use shared memory to exchange data. That is multiple number of
>
> > individual programs running glpk and getting their data from shared
>
> > memory.
>
> >
>
> >
>
> > Any other solution? Is there any implementation that you would
>
> > recommend?
>
>
>
> Please see
>
> http://lists.gnu.org/archive/html/help-glpk/2010-04/msg00038.html .
>
>
>
> If you are interested in this solution, I can post you a reentrant version
> of glpk/src/env/tls.c for GNU/Linux or MS Windows (from an old glpk
> distribution).
>
>
>
>
>
> Andrew Makhorin
>
>
>
>
>
>
>
> _______________________________________________
>
> Help-glpk mailing list
>
> [email protected]
>
> https://lists.gnu.org/mailman/listinfo/help-glpk
>
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