Re: [Getfem-commits] please merge branch devel-tetsuo-asm_lumped_mass_matrix

[Yves Renard]

Dear Tetsuo,

Your contribution can of course be interesting. I hope that you are 
aware that is has a limitation. This is valid only for order one 
elements (lumped matrices for higher order elements are rather difficult 
to build). It should be noted somewhere.

Another aspect: you implemented the lump with two loops which can be 
very inefficient for large matrices. So, can you test something as the 
following implementation

template<typename MAT>
  inline void asm_lumped_mass_matrix_for_first_order
  (const MAT &M, const mesh_im &mim, const mesh_fem &mf1,
   const mesh_region &rg = mesh_region::all_convexes()) {
    asm_mass_matrix(M, mim, mf1, rg);
    size_type nbd = gmm::mat_ncols(M), nbr = gmm::mat_nrows(M);
    GMM_ASSERT1(nbd == nbr, "mass matrix is not square");
    typedef typename linalg_traits<V>::value_type>::T value_type;
    std::vector<value_type> V(nbd), W(nbr);
    gmm::fill(V, T(1));
    gmm::mult(M, V, W);
    gmm::clear(const_cast<MAT &>(M));
    for (size_type i = 0; i < nbd; ++i)
       (const_cast<MAT &>(M))(i,i) = W[i];
 }

which should be more efficient.

Best regards,

Yves


Le 07/01/2019 à 04:55, Tetsuo Koyama a écrit :
> Dear GetFEM project
>
> P.S.
> I did a test in my local and checked.
> But I'm wondering where I should add test for new function.
> Thank you.
>
> Best Regard Tetsuo
>
> 2019年1月7日(月) 12:49 Tetsuo Koyama <address@hidden>:
> > Dear GetFEM project
> >
> > I added a asm_lumped_mass_matrix which calculate lumped mass matrix by
> > asm_mass_matrix.
> > I am planning to also add lumped mass to model object to use it for
> > dynamic response analysis.
> > I would appreciate having advice and comments.
> >
> > Best Regard Tetsuo


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  Yves Renard (address@hidden)       tel : (33) 04.72.43.87.08
  INSA-Lyon
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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