On Monday 19 November 2007 11:15, mikael gueguen wrote: > hi > what is the good way to write global matrix for FEM with gmm? > if i use a dense_matrix for writing the global matrix during the > assembly procedure, i have problem with large scale problem, > and if i use a col_matrix < gmm::wsvector<double> >, it 's not > possible to access the rows, and i cannot insert boundary condition. > > How can i resolve that? >
You mean you want to prescribe Dirichlet type boundary conditions (solution prescribed on the boundary) ? It depends on how you prescribe the boundary conditions. There is at least three possibilities : Adapt the stiffness matrix cleaning some lines of the matrix, penalization or Lagrange multipliers. For the first method, the optimal way if either to have a row matrix (row_matrix < gmm::wsvector<double> > or row_matrix < gmm::rsvector<double> > for instance) or if you have a column matrix, set to zero the potentialy non zero elements by considering the neighbor dofs (i.e. the dofs of the elements containing the dof to be prescribed). Yves. -- Yves Renard ([EMAIL PROTECTED]) tel : (33) 04.72.43.87.08 Pole de Mathematiques, INSA de 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
