Re: [Getfem-users] interpolated fem: gradient of the shape functions

[Andriy Andreykiv]

Little correction to the previous code (I didn't do the copy paste correctly)
the second line of the code was not

getfem::pfem fem=getfem::new_interpolated_fem(mf_QuadMesh,mim);

but

getfem::pfem ifem=getfem::new_interpolated_fem(mf_QuadMesh,mim);
(hence, my problems are not caused by a typing mistake)


But this doesn't change the essence of my question regarding the the 
interpolation of the base functions gradient on another fem

Regards,
                        Andriy

On Monday 28 May 2007 19:17, Andriy Andreykiv wrote:
> Dear Yves and Julien,
>
> Would you be so kind to consult me on the following:
>
>     I'm using the interpolated fem (new_interpolated_fem) in an FE
> model, based on fictitious domain method. For instance I was already
> able to successfully build a mass matrix between the mesh_fem's defined
> on two overlapping meshes that was used to impose Dirichlet boundary
> conditions in a week sense:
> ___________________________________________________________________________
>_____________________ 
>getfem::mesh_fem mq_interpolate(line_mesh);  
> //LINE_MESH='GT_PK(1,1)' getfem::pfem
> fem=getfem::new_interpolated_fem(mf_QuadMesh,mim);
> //MF_QUADMESH='FEM_QK(2,1)';
> mq_interpolate.set_finite_element(line_mesh.convex_index(),ifem);
> size_type n=mq_interpolate.nb_dof(),m=mf_line.nb_dof(); /MF_LINE =
> 'FEM_PK(1,1)';
> sparse_matrix M(n,m);
> getfem::generic_assembly assem;
> assem.set("M(#1,#2)+=comp(Base(#1).Base(#2))");
> assem.push_mi(mim);
> assem.push_mf(mq_interpolate);
> assem.push_mf(mf_line);
> assem.push_mat(M);
> assem.assembly();
> ___________________________________________________________________________
>______________________
>
> The above works perfect. However, now I want to interpolate the gradient
> of the shape functions from the quad mesh on the line mesh and calculate
> something like this:
>
> 1) assem.set("M(#1,#2)+=comp(Grad(#1).Base(#2))(:,i,:)");
> 2) assem.set("M(#1,#1)+=comp(Grad(#1).Grad(#1))(:,i,:,i)"); // with
> M(n,n)
> 3) assem.set("M(#1,#1)+=comp(vGrad(#1).vGrad(#1))(:,i,j,:,i,j)"); //
> with M(n,n)
>
> and so on
>
>
>
> In all cases I'm getting an error message:
>
>
> ===========================================================
>
> |    An error has been detected !!!
>
> ===========================================================
> Error in getfem_mat_elem.cc, line 352:
> Internal error
>
> *** Exited with status: 1 ***
>
>
> Is this a bug? Or I'm doing something wrong? If this is a bug, could
> you, please, suggest a fix or a different way to obtain those matrices?
>
> Thank you in advance,
>                       Andriy

-- 
__________________________________________
Andriy Andreykiv
Delft University of Technology
Faculty of Mechanical Engineering 
Fundamentals of Microsystems
Mekelweg 2
2628 CD  Delft
The Netherlands

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