Dear Yves, I just started using getfem, so I am afraid my questions quite trivial. I wanted to ask/confirm a couple of more things:
> mf.ind_dof_of_element(icv) gives the dof number of element icv I was wondering if the same thing can be achieved by another method. Since the subdomains are defined by mesh_regions, looking again at interpolation functions, they take in a mesh_region as argument. So, if I call interpolation_function multiple times (once for each mesh_region) and pass in the same vector, each interpolation_function will only fill in the part of the vector corresponding to its dof's. This way I should be able to get piecewise constant coefficients for each region. Is this correct? Thanks, -Jehanzeb On Wed, Jul 8, 2009 at 11:24 AM, Yves Renard<[email protected]> wrote: > > Dear Jehanzeb, > > This is the same of all finite element method. The function > > mf.ind_dof_of_element(icv) > > gives the dof number of element icv (a unique dof for the P0 method), and the > function > > mf.point_of_dof(idof) > > gives the coordinate of the finite element node. With this, is is not > difficult to fill the vector of dof (without any additional storage). > > Yves. > > > > On mercredi 8 juillet 2009, Jehanzeb Hameed wrote: >> Is there a simple way in getfem to map points to convexes, that is: >> > the interpolation point for each element is the barycenter. So you >> > can discriminate in wich part of your domain is the point. >> >> Given the particular barycenter, say 'b', do I have to build a list of >> all barycenters in the beginning, and then search for 'b' in that >> list? Or is there some already builtin way to go about it. >> >> Thanks, >> -Jehanzeb >> >> On Wed, Jul 8, 2009 at 4:50 AM, Yves Renard<[email protected]> wrote: >> > On mardi 7 juillet 2009, Jehanzeb Hameed wrote: >> >> Hello, >> >> >> >> In laplacian.cc "getfem::classical_fem(pgt,0))" is used to represent >> >> the fem space for coefficient function (mf_coef). This coefficient >> >> function is constant on each convex. It is not used in laplacian.cc, >> >> and is set to one by creating a vector ones ( >> >> std::vector<scalar_type>(mf_coef.nb_dof(), 1.0) ). >> >> >> >> Now say, I want to this coefficient to be piecewise constant, that is >> >> constant on each of (say two) subdomains. It seems I cant use >> >> interpolation for it, as interpolation functions use coordinates of >> >> points, and dont seem to indicate which convex they come from. >> > >> > Indeed you can. If you represent your coefficient on a P0 method >> > (piecewise constant), the interpolation point for each element is the >> > barycenter. So you can discriminate in wich part of your domain is the >> > point. If you want to fill the corresponding vector by hand, you can use >> > the method >> > mf.point_of_dof(i) for the P0 method which will give you the coordinates >> > of the corresponding barycenter. Otherwise, you can also use the >> > interpolation functions. >> > >> > Yves. >> > >> >> One way >> >> I can think of doing it, is to loop for mesh convexes, look up which >> >> region the convex belongs to, and then set the corresponding entry in >> >> the coefficient vector. However I am not sure if this is the way to >> >> go, as numbering of convexes in the mesh may not correspond to >> >> numbering of dof's of the vector passed as data for assembly. >> >> >> >> Is the above method the one to use, or is there a more elegant way >> >> around this? >> >> >> >> Thanks, >> >> -Jehanzeb >> >> >> >> _______________________________________________ >> >> Getfem-users mailing list >> >> [email protected] >> >> https://mail.gna.org/listinfo/getfem-users >> > >> > -- >> > >> > Yves Renard ([email protected]) tel : (33) 04.72.43.87.08 >> > Pole de Mathematiques, INSA-Lyon fax : (33) 04.72.43.85.29 >> > 20, rue Albert Einstein >> > 69621 Villeurbanne Cedex, FRANCE >> > http://math.univ-lyon1.fr/~renard >> > >> > --------- > > > > -- > > Yves Renard ([email protected]) tel : (33) 04.72.43.87.08 > Pole de Mathematiques, INSA-Lyon fax : (33) 04.72.43.85.29 > 20, rue Albert Einstein > 69621 Villeurbanne Cedex, FRANCE > http://math.univ-lyon1.fr/~renard > > --------- > _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
