I want to assemble only a few parts of the marix. So I thought about working with LocalAssembler.assemble(). I don't quite get, what it does.
static void assemble(Eigen::MatrixXd& A, UFC& ufc, const std::vector& vertex_coordinates, ufc::cell& ufc_cell, const Cell& cell, const MeshFunction* cell_domains, const MeshFunction* exterior_facet_domains, const MeshFunction* interior_facet_domains)
is what the help say's.
What size has MatrixXd A?
I suppose cell, vertex_coordinates and ufc_cell belong to the cell I want to integrate over.
But what is with the MeshFunctions? Have I do them for the whole Mesh or only for the Cell?
And my last question: What element of the returned Matrix A belongs to what degree of freedom?
Thanks for your help!
