Thank you very much, now it works. to completeness to the future readers, I would like to correct a typo I made when asking for the command. K= --equation-- gf_model_set(md, 'add initialized data', 'K', [K]); gf_asm('generic', mim3, 2, 'K*(Test_ut.*ut)', -1, 'ut', 1, mf3, zeros(gf_mesh_fem_get(mf3, 'nbdof'),1), 'K' , 0, K);
Again, thank you, Have a nice day Nicolò Cambiaso Il giorno lun 30 set 2019 alle ore 22:19 Yves Renard < yves.ren...@insa-lyon.fr> ha scritto: > > Dear Nicolo Cambiaso, > > You can use gf_asm to produce a mass matrix as you tried, but you have to > specify a fem on which the variable is described. The correct syntax is for > instance > > gf_asm('generic', mim3, 2, 'Grad_Test2_ut.Grad_Test_ut', -1, 'ut',1, mf, > zero(gf_mesh_fem_get(mf, 'nbdof'),1)); > > where mf is the mesh_fem structure describing the fem. > > Best regards, > > Y.R. > > ----- Mail original ----- > De: "Nicolò Cambiaso" <cambiaso.nic...@gmail.com> > À: "getfem-users" <getfem-users@nongnu.org> > Envoyé: Lundi 30 Septembre 2019 12:25:51 > Objet: [Getfem-users] Generic Bricks definition using gf_asm. > > Dear users, > I would like to solve a system of equations using Getfemm++ with Matlab > interface. > So I created a block matrix, and now i cannot create the corresponding > bricks. > I'm using the command "gf_asm", hoping it's the correct one. > > the block is the following: > Mtt=1/k u_t v_t. (v_t is the test function corresponding to u_t) > in full despair, i also removed the 1/k therm, and still nothing worked. > this is what i wrote: > > gf_asm('generic', mim3, 2, 'Grad_Test2_ut.Grad_Test_ut', -1, 'ut',1, U); > > And the error message is: > > "Error using gf_matlab > Error in getfem_generic_assembly.cc, line 9519 void > getfem::ga_node_analysis(const string&, getfem::ga_tree&, const > getfem::ga_workspace&, getfem::pga_tree_node, bgeot::size_type, > bgeot::size_type, bool, bool, int): > Error in assembly string > > Error in gf_asm (line 338) > [varargout{1:nargout}]=gf_matlab('asm', varargin{:}); > > Error in Comeon (line 56) > Mtt=gf_asm('generic', mim3, 2, 'Grad_Test2_ut.Grad_Test_ut', -1, 'ut',1, > U); % M_tt, proviamo" > > with > mim3= gf_mesh_im( mf3, gf_integ('IM_NC(3,1)') ) > mf3=gf_mesh_fem(OmegaM,3) > OmegaM=gf_mesh('regular simplices',vectX, vectY, vectZ, 'degree', 1) > > at his point, i defined U as ones(2,2,2,3), having the vectX(/Y/Z) only 2 > points each one, for now, and because u_t is a 3D vector. > I think that's not correct, but i have no idea of the correct dimension of > U, and i tried everything that came to my mind ... and still nothing > worked. > > I found a lot of material dealing with this on c++ interface, but > unfortunately I cannot male it work in Matlab. > > thank you very much, > Nicolo Cambiaso. >