[Dune-devel] dune-common update seems to cause error in my ParMetis routine

[Christian Engwer]

On Fri, Jan 22, 2016 at 02:56:30PM +0100, Aleksejs Fomins wrote:
> Dear Christian,
> 
> Ok, the celebration was a little too soon. Now the previous error is gone and I get the same error in Metis, namely
> 
> -----------------------------------------------------------------------------------------------------------------------
> /opt/extlib/parmetis/4.0.3/openmpi/1.10.0/gcc/5.2.0/include/metis.h:187:34: error: reference to ‘real_t’ is ambiguous
>                    idx_t *nparts, real_t *tpwgts, real_t *ubvec, idx_t *options, 
>                                   ^
> /opt/extlib/parmetis/4.0.3/openmpi/1.10.0/gcc/5.2.0/include/metis.h:120:17: note: candidates are: typedef float real_t
>    typedef float real_t;
>                  ^
> In file included from /home/fomins/gitwork/hades-lspr-ag/dune-common/dune/common/fvector.hh:15:0,
>                  from /home/fomins/gitwork/hades-lspr-ag/dune-common/dune/common/fmatrix.hh:13,
>                  from /home/fomins/gitwork/hades-lspr-ag/hades/stdincl/hadestypes.hh:33,
>                  from /home/fomins/gitwork/hades-lspr-ag/hades/hadesx/3d/dg/fd/hades3ddgfdx.hh:39,
>                  from /home/fomins/gitwork/hades-lspr-ag/hades/hadesx/3d/dg/fd/hades3ddgfdx.cc:17:
> /home/fomins/gitwork/hades-lspr-ag/dune-common/dune/common/typetraits.hh:565:55: note:                 template<class Type> using real_t = typename Dune::FieldTraits::real_type
>    using real_t = typename FieldTraits<Type>::real_type;
> -----------------------------------------------------------------------------------------------------------------------
> 
> Any suggestions?

My suggestion is that you either have a broken compiler or broken
code. As dune puts the real_t into namespace Dune it should not
collide. As it obviously does, either your compiler does something
wrong (which one are you using?) or you somehow inject the metis
typedef into the Dune namespace.

Christian

> Regards,
> Aleksejs
> 
> On 22.01.2016 13:45, Christian Engwer wrote:
> > On Fri, Jan 22, 2016 at 01:41:43PM +0100, Aleksejs Fomins wrote:
> >> Dear Christian,
> >>
> >> Thank you for your advice. After a brief look at the commit tree, I have found a commit 
> >>
> >> 93f16b5ecdb60704cc9c369a9ee14f24708c506a
> >>
> >> by Lars Lubkoll as of 2015-12-07 16:08:42, which adds the line
> >>
> >> using real_t = typename FieldTraits<Type>::real_type;
> >>
> >> to namespace Dune.
> >>
> >>
> >> Since curvilinear grid is inside namespace Dune, I suppose that including parmetis.h creates a name clash.
> >>
> >>
> >> Do you think that
> >>
> >> namespace MyParmetis{
> >>   #include <parmetis.h>
> >> }
> >>
> >> would be a good solution?
> > 
> > No! This will craete completely different names and linking will
> > fail. You will have to use proper scoping. ::real_t will refer to the
> > global name and not the one in the Dune namespace.
> > 
> > Christian
> > 
> >> Best,
> >> Aleksejs
> >>
> >>
> >> On 22.01.2016 13:14, Christian Engwer wrote:
> >>> Easiest wuld be a git bisect to identify te commit that caused the
> >>> problems.
> >>>
> >>> Alternatively you can look at the preprocessor output.
> >>>
> >>> Christian
> >>>
> >>> On Fri, Jan 22, 2016 at 12:13:58PM +0100, Aleksejs Fomins wrote:
> >>>> Dear Markus,
> >>>>
> >>>> real_t is a datatype that is essentially float or double, as defined in <parmetis.h>, which is included in the file in question.
> >>>>
> >>>> In fact, the error disappears if I manually type
> >>>>
> >>>> typedef float real_t;
> >>>>
> >>>> inside of my code. However, this same line is already written in parmetis.h, and the compiler clearly sees this file, because it does not complain about other parmetis functions I use. What puzzles me is that the code compiles no problem with previous version of dune-common.
> >>>>
> >>>> Thanks,
> >>>> Aleksejs
> >>>>
> >>>>
> >>>> On 22.01.2016 12:07, Markus Blatt wrote:
> >>>>> Hi,
> >>>>>
> >>>>> On Fri, Jan 22, 2016 at 11:55:31AM +0100, Aleksejs Fomins wrote:
> >>>>>> My Parmetis code, which used to compile before, includes the following lines:
> >>>>>>
> >>>>>> ------------------------------------------------------------------------------
> >>>>>> #if PARMETIS_MAJOR_VERSION < 4
> >>>>>>       typedef idxtype idx_t;
> >>>>>>       typedef float real_t;
> >>>>>> #endif
> >>>>>>
> >>>>>> std::vector<real_t> tpwgts(ncon*nparts, 1./nparts);
> >>>>>> ------------------------------------------------------------------------------
> >>>>>>
> >>>>>> With the latest pull of dune-common, I get the following error
> >>>>>>
> >>>>>> ------------------------------------------------------------------------------
> >>>>>> /home/fomins/gitwork/hades-lspr-ag/dune-curvilineargrid/dune/curvilineargrid/io/file/curvilineargmshreader.hh:1124:25: error: type/value mismatch at argument 1 in template parameter list for ‘template<class _Tp, class _Alloc> class std::vector’
> >>>>>>        std::vector<real_t> tpwgts(ncon*nparts, 1./nparts);
> >>>>>>                          ^
> >>>>>> /home/fomins/gitwork/hades-lspr-ag/dune-curvilineargrid/dune/curvilineargrid/io/file/curvilineargmshreader.hh:1124:25: note:   expected a type, got ‘real_t’
> >>>>>> ------------------------------------------------------------------------------
> >>>>>>
> >>>>>> Would you be so kind as to suggest what caused this error and how to correct it?
> >>>>>
> >>>>> The error message is pretty clear: The compiler does not know real_t
> >>>>> for whatever reason. What is it supposed to be?
> >>>>>
> >>>>> Cheers,
> >>>>>
> >>>>> Markus
> >>>>>
> >>>>
> >>>> _______________________________________________
> >>>> Dune-devel mailing list
> >>>> Dune-devel at dune-project.org
> >>>> http://lists.dune-project.org/mailman/listinfo/dune-devel
> >>>
> >>
> > 
> 

-- 
Prof. Dr. Christian Engwer 
Institut für Numerische und Angewandte Mathematik
Fachbereich Mathematik und Informatik der Universität Münster
Einsteinstrasse 62
48149 Münster

E-Mail  christian.engwer at uni-muenster.de
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