dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Sat, Apr 01, 2006 at 08:24:02PM +0200, Garth N. Wells wrote:
> On Sat, 2006-04-01 at 06:52 -0600, Anders Logg wrote:
> > On Sat, Apr 01, 2006 at 11:25:16AM +0200, Garth N. Wells wrote:
> > > On Fri, 2006-03-31 at 13:11 -0600, Anders Logg wrote:
> > > > On Fri, Mar 31, 2006 at 06:22:39PM +0200, Garth N. Wells wrote:
> > > > > On Fri, 2006-03-31 at 10:17 -0600, Robert C. Kirby wrote:
> > > > > > >
> > > > > > > I downloaded boost, pulled the header files out and dropped them  
> > > > > > > into my
> > > > > > > directory and it worked fine, so it appears that no binary  
> > > > > > > libraries are
> > > > > > > involved. I did a grep on the header files, and the dependency on  
> > > > > > > other
> > > > > > > boost components is limited.
> > > > > > >
> > > > > > 
> > > > > > Is there any license issue to just stuffing the requisite .h files  
> > > > > > into DOLFIN?
> > > > > > 
> > > > > 
> > > > > No. The Boost license is more liberal the GPL. You can find it here
> > > > > http://www.boost.org/LICENSE_1_0.txt.
> > > > > 
> > > > > Garth
> > > > 
> > > > I'm not sure. If you look in the GPL FAQ which is available at
> > > > http://www.gnu.org/licenses/gpl-faq.html you find the following answer
> > > > to the question "What is the difference between "mere aggregation" and "combining two
> > > > modules into one program?":
> > > > 
> > > >     Mere aggregation of two programs means putting them side by side
> > > >     on the same CD-ROM or hard disk. We use this term in the case
> > > >     where they are separate programs, not parts of a single
> > > >     program. In this case, if one of the programs is covered by the
> > > >     GPL, it has no effect on the other program.
> > > > 
> > > > --> Combining two modules means connecting them together so that they
> > > > --> form a single larger program. If either part is covered by the
> > > > --> GPL, the whole combination must also be released under the GPL--if
> > > > --> you can't, or won't, do that, you may not combine them.
> > > > 
> > > >     What constitutes combining two parts into one program? This is a
> > > >     legal question, which ultimately judges will decide. We believe
> > > >     that a proper criterion depends both on the mechanism of
> > > >     communication (exec, pipes, rpc, function calls within a shared
> > > >     address space, etc.) and the semantics of the communication (what
> > > >     kinds of information are interchanged).
> > > > 
> > > >     If the modules are included in the same executable file, they are
> > > >     definitely combined in one program. If modules are designed to run
> > > >     linked together in a shared address space, that almost surely
> > > >     means combining them into one program.
> > > > 
> > > >     By contrast, pipes, sockets and command-line arguments are
> > > >     communication mechanisms normally used between two separate
> > > >     programs. So when they are used for communication, the modules
> > > >     normally are separate programs. But if the semantics of the
> > > >     communication are intimate enough, exchanging complex internal
> > > >     data structures, that too could be a basis to consider the two
> > > >     parts as combined into a larger program. 
> > > > 
> > > > You could interpret this as if we distribute ublas as part of DOLFIN,
> > > > then ublas must be licensed under the GPL, which we can't do?
> > > > 
> > > > On the other hand, the boost license is listed as compatible with the
> > > > GPL so I guess it should be ok:
> > > > 
> > > >     http://www.gnu.org/philosophy/license-list.html
> > > > 
> > > > /Anders
> > > > 
> > > 
> > > Looks ok to me since it's GPL-compatible. From
> > > http://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses
> > > 
> > >     "We classify a license according to certain key questions:
> > > 
> > >         * Whether it qualifies as a free software license.
> > >         * Whether it is a copyleft license.
> > > -->     * Whether it is compatible with the GNU GPL. (This means 
> > >           you can combine a module which was released under that 
> > >           license with a GPL-covered module to make one larger program.)
> > >         * Whether it causes any particular practical problems."
> > > 
> > > 
> > > Garth
> > 
> > Yes, looks ok.
> > 
> > What is logic behind including ublas and not other dependencies? Why
> > don't we include libxml2 and PETSc? In the first case perhaps because
> > it may be considered more standard than ublas and be expected to be
> > present and in the second case because it's too big...
> > 
> 
> I thought about this and some reasons to include it are (in no
> particular order)
> 
> 1. uBlas is not a binary library, so it seems natural to include it (not
> sure that this is a legitimate motivation).
> 
> 2. It is small, so the cost in terms of the increased size of the DOLFIN
> source package is minimal, while the benefit is that we avoid an extra
> dependency.
> 
> 3. Boost has a non-standard build procedure that may confuse some users,
> while uBlas does not need to be built. Also the default installation
> location of Boost is version dependent, so it is likely that users will
> have to specify the location manually.

All seem to be compelling reasons...

> A reason not to include it is that it is available as a package for most
> Linux distributions and for Cygwin. Another reason not to include it and
> to make it a dependency is if we wish to exploit more Boost libraries in
> the future we don't have to be shy about it. I can see the Boost
> libraries multi_array, static_assert, random and python possibly being
> useful.
>
> What I'll do is first not add ublas in the development version of DOLFIN
> and see how everybody goes building it. It should be straightforward to
> install the Boost package. If it proves problematic, we can add the
> ublas code later.

That's a good plan.

I suspect I will only need to do apt-get install libboost-dev...

/Anders