On Fri, Apr 2, 2010 at 11:01 PM, Karen Lee <[email protected]> wrote: > Dear all, > > I'm wondering if anyone knows how I might calculate the gradient of my > solution (an electric potential) in 3D. Basically I would like to have the > electric field vector associated at the nodes for which I have the potential > value... Does anyone know how I might do that? Either doing that with the > output I already have or doing it in the solver itself would be awesome. The > potential was obtained from a Poisson's equation.
Check out one of the nonlinear examples like ex13. For each element we need to recompute the velocity gradient from the old timestep and current Newton step, and we do it by looping over the element dofs and adding up the contributions grad_u = sum_i u_i dphi_i In the examples this is done at interior (Gauss) quadrature points but you could follow the same procedure using a nodal quadrature rule instead. -- John ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
