Dear Umut,
I your exemple, you should define two mesh_fems as follows :
getfem::mesh_fem meshFemCore1(mshGmsh);
// region 1, scalar domain, pressure field, dimension 1
for(getfem::mr_visitor i(region1); !i.finished(); ++i){
meshFemCore1.set_finite_element(i.cv(),getfem::fem_descriptor("FEM_QK(3,
1)"));
}
meshFemCore.set_qdim(1); // not really necessary.
getfem::mesh_fem meshFemCore2(mshGmsh);
// region 2, vectorial domain, displacement field, dimension 3
for(getfem::mr_visitor i(region2); !i.finished(); ++i){
meshFemCore2.set_finite_element(i.cv(),getfem::fem_descriptor("FEM_QK(3,
1)"));
}
meshFemCore.set_qdim(3);
Then, you can use these two mesh_fem objects in the assembly procedure
in order to compute your coupling term.
Regards,
Yves.
Umut Tabak <[email protected]> a écrit :
> Renard Yves wrote:
>>
>> Umut Tabak <[email protected]> a écrit :
>>
>>> Renard Yves wrote:
>>>>
>>>> Umut Tabak <[email protected]> a écrit :
>>>>
>>>>> Renard Yves wrote:
>>>>>>
>>>>>> Dear Umut,
>>>>>>
>>> Hi again,
>>>
>>> I tried to apply a sample analysis where I can assemble the fluid
>>> part(scalar) and the structural part(displacement). Now I have a
>>> problem concerning the coupling matrix assembly. I attached the
>>> code and the necessary msh files. Now the questions are(better to
>>> answer these after taking a look at the source file attached. In
>>> brief, I have 3 mesh structures and 3 mesh_fems attached to these
>>> mesh structures and the operations should be clear for you.)
>>>
>>> + To have this kind of analysis(coupled structural-acoustic), we
>>> have to set the mesh_fem dimensions to 3 and 1 for the structural
>>> and fluid parts respectively, if there is only one mesh_fem
>>> definition, how can I assign different dimensions to different
>>> regions of my mesh?
>>
>> You cannot ! Even if you have only one mesh representing both the
>> structure and the fluid, the best is to have two mesh_fem, each
>> defined only on the corresponding region. This is the easiest for
>> computing the coupling terms but of course it means that the meshes
>> of the structure and the fluid match to each other.
>> If you have two separate meshes you can try to compute the coupling
>> term using the object "interpolated fem" which interpolate a fem
>> from a mesh to another (see for instance
>> tests/test_interpolated_fem.cc)
> Dear Professor Renard,
>
> That is the question I am still puzzling with, how to assign two
> mesh_fems to different regions of a mesh, I am sorry again but let
> me ask one more, I can iterate over regions as you have suggested,
> to assign pfem definitions, but how to change the dimensions of the
> these regions? As far as, I can understand from your definitions, I
> can have one mesh and different mesh_fem definitions for different
> regions. I could partly accomplish this task by assigning the pfem
> by iteration but I still could not understand how to change the
> target dimension, Or do I have a conceptual misunderstanding on this
> point? Or there is a trick to do this that I am still missing? There
> is a simple code below to explain my purposes.
>
> Best regards,
>
> Umut
>
> A very simple code vhere I think the dimensions also be changed, but
> you are the creator of the library.
>
> // standard headers
> #include <iostream>
> #include <vector>
> #include <string>
> #include <cstdlib>
> #include <cassert>
> #include <stdexcept>
> // gmm++ headers, pay attention that this is a template
> // library, so that no build is required.
> #include <gmm/gmm.h>
> #include <gmm/gmm_inoutput.h>
> // getFem++ headers
> #include <getfem/getfem_import.h>
> #include <getfem/dal_bit_vector.h>
> #include <getfem/getfem_mesh.h>
> #include <getfem/getfem_mesh_fem.h>
> #include <getfem/getfem_partial_mesh_fem.h>
> #include <getfem/getfem_mesh_im.h>
> #include <getfem/getfem_integration.h>
> #include <getfem/getfem_assembling.h>
> #include <getfem/getfem_modeling.h>
> #include <getfem/getfem_regular_meshes.h>
> //
> typedef getfem::modeling_standard_sparse_matrix sparse_matrix;
> //using namespace getfem;
> //using namespace gmm;
> using namespace std;
> //
> int main(int argc, char** argv)
> {
> try{
> getfem::mesh mshGmsh;
> getfem::import_mesh("gmshv2:./boxSolidCheck.msh", mshGmsh);
> // region 1 is the fluid part of the model mesh definition
> if(mshGmsh.has_region(1))
> cout << "Region 1 is defined" << endl;
> if(mshGmsh.has_region(2))
> cout << "Region 2 is defined" << endl;
> if(mshGmsh.has_region(3))
> cout << "Region 3 is defined" << endl;
> getfem::mesh_region region1(mshGmsh.region(1));
> getfem::mesh_region region2(mshGmsh.region(2));
> getfem::mesh_region region3(mshGmsh.region(3));
> // optional print out for the convexes(elements) of a specific
> // region
> cout << "Number of elements in region 1 is " <<
> region1.nb_convex() << endl;
> cout << "Number of elements in region 2 is " <<
> region2.nb_convex() << endl;
> cout << "Number of elements in region 3 is " <<
> region3.nb_convex() << endl;
> // can also be an array of vectors
> if(region1.is_only_convexes()) cout << "region 1
> only contains convexes" << endl;
> else
> cout << "region 1 is not composed of convexes only" << endl;
> //
> dal::bit_vector elemsInRegion1= region1.index();
> dal::bit_vector elemsInRegion2= region2.index();
> dal::bit_vector elemsInRegion3= region3.index();
> //
> for(getfem::mr_visitor i(region1);!i.finished();++i){
> cout << "Element :" << i.cv() << " in region1." << endl;
> }
> // assign fem definitions to the regions
> getfem::mesh_fem meshFemCore(mshGmsh);
> // region 1, scalar domain, pressure field, dimension 1
> for(getfem::mr_visitor i(region1); !i.finished(); ++i){
>
> meshFemCore.set_finite_element(i.cv(),getfem::fem_descriptor("FEM_QK(3,
> 1)"));
> // should not dimensions set here??
> }
> // region 2, vectorial domain, displacement field, dimension 3
> for(getfem::mr_visitor i(region2); !i.finished(); ++i){
>
> meshFemCore.set_finite_element(i.cv(),getfem::fem_descriptor("FEM_QK(3,
> 1)"));
> // should not dimensions set here??
> }
>
> }
> catch(std::exception &e){
> std::cout << e.what() << std::endl;
> }
> return EXIT_SUCCESS;
> }
>
>
>
>
>
>
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