On Thu, 14 Mar 2019, Renato Poli wrote:
> How do I change the dof ordering options? "-pc_factor_mat_ordering_type string" with a string from https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatOrderingType.html#MatOrderingType > Add a SCALAR variable to use as a Lagrange multiplier? > > This sounds like a much cleaner solution. > I could not understand how to do that in libmesh so far. > It is probably time to put some more effort here... > > I see I must add a Kp_alpha matrix. Do I need the Kalpha_p as well? Yes; the Kalpha_p ends up being what looks most like the actual constraint equation. ... Except you don't have a constraint *equation* here, you have constraint *equations*. You wouldn't want a SCALAR lagrange multiplier, you'd want to add a LAGRANGE variable subdomain-restricted to boundary elements along the constrained domain boundary... this is sounding like more trouble than it's worth unless you can't get the directly constrained solves to converge. --- Roy _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
