On Thu, 18 Aug 2016, John Peterson wrote: > On Thu, Aug 18, 2016 at 2:58 AM, <li....@siat.ac.cn> wrote: > >> I want to get the hessian on a mesh point. >> I find that there is a function point_hessian in fem_context.C. >> How can I get a FEMContext object? I don't have "context" in my code. >> FEMContext &c = libmesh_cast_ref<FEMContext&>(context); > > You have to be using the FEMSystem stuff for FEMContexts to be available. > See examples/fem_system.
This actually hasn't been true for a while - while you can't use a non-trivial FEMSystem without computing using the FEMContext objects it gives you, you can build and use FEMContext objects with any other system type. There's also a System::point_hessian() function that's available in all the system classes, and if you really want the hessian on *a* mesh point then that's the way to go, but if you want the hessian on *lots of* mesh point*s* then the point locator which the element-free overload of System::point_hessian() uses is an unnecessarily expensive way to do that. --- Roy ------------------------------------------------------------------------------ _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
