Re: [Libmesh-users] [Libmesh-devel] Subdomain_id not getting set when reading Gmsh meshes

[David K. <dknez@MIT.EDU>]

I added elem->subdomain_id() = physical; on line 490 of GmshIO.C a while 
back in order to set element subdomain_id's based on gmsh physicals, and 
that worked for me... Arvind, are you using an updated version of libMesh?

Vijay: please send your patch to the list again, it should definitely be 
checked-in!

- Dave



Vijay S. Mahadevan wrote:
> Arvind,
>
> The reason for this is that the attributes are ignored when they are
> read in from the .msh file. I sent in a patch for this a long time
> back but I'm not entirely sure whether it was updated. Of course, I
> have added more things to my version of Gmsh reader/writer in libMesh
> to suit my needs which includes updating the subdomain_id, and the
> surface_id/volume_id  if you want it.
>
> Meanwhile you might want to look at GmshIO's read/write implementation
> where they parse the attributes. The physical region is usually the
> first attribute that is read after the element_id and num_attributes.
>
> I'm not on my work computer now but I can probably create a new patch
> against the working copy and send it over tomorrow.
>
> Vijay
>
> On Tue, Oct 27, 2009 at 6:07 PM, Arvind Ajoy <arv...@gm...> wrote:
>   
>> Dear Users and Developers
>>
>> I am trying to read in a simple mesh created using Gmsh, which has two
>> Physical regions.
>> I use the example programme ex1.cc to read the .msh file, and write it out
>> as another
>> .msh file, i.e ./ex1 -d 2 in.msh out.msh.
>>
>> I find that the output of ex1.cc mentions n_subdomains()=1, though there are
>> two physical
>> regions.
>>
>> Mesh Information:
>>   mesh_dimension()=2
>>   spatial_dimension()=3
>>   n_nodes()=45
>>     n_local_nodes()=45
>>   n_elem()=32
>>     n_local_elem()=32
>>     n_active_elem()=32
>>   n_subdomains()=1
>>   n_processors()=1
>>   processor_id()=0
>>
>> Also, when I look at the out.msh file, I notice that there is only one
>> Physical region!
>>
>> I have tried with both the Gmsh v1 and v2 formats. My libmesh version
>> corresponds
>> to the svn trunk.
>>
>> I have searched extensively on the archives, but didnt find a solution to my
>> problem.
>> Can someone with experience with Gmsh import throw more light on this issue?
>>
>> Thanks.
>> Regards
>>
>> Arvind Ajoy
>>
>>
>>
>> The Gmsh in.geo file is as under ........
>>
>> ==================================================================
>> a = 1;
>>
>> // 4    3    6
>> // +    +    +
>> //
>> //
>> //
>> //
>> // +    +    +
>> // 1    2    5
>>
>> Point(1) = {0, 0, 0};
>> Point(2) = {a, 0, 0} ;
>> Point(3) = {a, a, 0} ;
>> Point(4) = {0, a, 0} ;
>> Point(5) = {2*a,0, 0};
>> Point(6) = {2*a,a, 0};
>>
>> Line(1) = {1,2} ;
>> Line(2) = {3,2} ;
>> Line(3) = {3,4} ;
>> Line(4) = {4,1} ;
>> Line(5) = {2,5} ;
>> Line(6) = {5,6} ;
>> Line(7) = {6,3} ;
>>
>> Line Loop(8) = {4,1,-2,3} ;
>> Line Loop(9) = {5,6,7,2};
>> Ruled Surface(10) = {8} ;
>> Ruled Surface(11) = {9} ;
>>
>> Transfinite Line{4} = 5 ;
>> Transfinite Line{2} = 5 ;
>> Transfinite Line{1} = 5 ;
>> Transfinite Line{3} = 5 ;
>> Transfinite Line{5} = 5 ;
>> Transfinite Line{6} = 5 ;
>> Transfinite Line{7} = 5 ;
>>
>> Transfinite Surface{10} = {1,2,3,4};
>> Transfinite Surface{11} = {2,5,6,3};
>> // (Note that the list on the right hand side refers to points, not
>> // curves.
>>
>> // Recombine the triangles into quads
>> Recombine Surface{10};
>> Recombine Surface{11};
>>
>> Physical Surface (100) = {10};
>> Physical Surface (200) = {11};
>> Physical Line (300) = {1,5,6,7,3,4};
>> ================================================================
>>
>>
>> ------------------------------------------------------------------------------
>> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
>> is the only developer event you need to attend this year. Jumpstart your
>> developing skills, take BlackBerry mobile applications to market and stay
>> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
>> http://p.sf.net/sfu/devconference
>> _______________________________________________
>> Libmesh-devel mailing list
>> Lib...@li...
>> https://lists.sourceforge.net/lists/listinfo/libmesh-devel
>>
>>
>>     
>
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay 
> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
> http://p.sf.net/sfu/devconference
> _______________________________________________
> Libmesh-devel mailing list
> Lib...@li...
> https://lists.sourceforge.net/lists/listinfo/libmesh-devel
>