Dear Yvonne DeMedici,
I understand that you use the Matlab interface. There should be a message accompagning the error "Error in assembly string". Probably, in your case, "vt" as not been properly added to the model. In order to be used in an assembly string, a data has to be added to the model first. If it is a vector or tensor data, it has to be declared accordingly. Best regards, Yves ----- Mail original ----- De: "Yvonne DeMedici" <y.demed...@yahoo.com> À: "getfem-users" <getfem-users@nongnu.org> Envoyé: Vendredi 25 Octobre 2019 10:18:26 Objet: Vector Data as Parameter Dear GetFem++ community, Thank you very much for you attention. I'm trying to implement a Heat transfer equation, and I successfully inserted in the model every single brick including the transient term, a part from the convection (or advection) term. My variational form of this term would be \int T \textbf{v} \cdot \Nabla \xi (with \xi test function Test_T, and \textbf{v} a known vector field). Let's make things easier and let me define the degrees of freedon as >>dof=gf_mesh_fem_get(mf, 'nbdof'); and \textbf{v} as >>vt=ones(dof, dof, 3).My problem is the fact that, using the command >>gf_model_set(md, 'add nonlinear generic assembly brick', mim, >>'(vt*T).Grad_test_T', -1); with T Temperature as the unknown variable, I receive the error>>"Error in assembly string". Could you help me understand what is happening here? Thank you again, Best wishes DeMedici Y.