Re: [Libmesh-users] Derivatives of shape functions at node points

2015-08-05 Thread Roy Stogner
On Thu, 23 Jul 2015, Paul T. Bauman wrote: > On Wed, Jul 22, 2015 at 7:13 PM, Sahai, Amal wrote: > >> I have a system with 3 variables, representing the x,y,z component of a >> quantity. I solved this system to obtain the component wise distribution in >> a given domain. I would now like to calc

Re: [Libmesh-users] Derivatives of shape functions at node points

2015-07-23 Thread Vikram Garg
One way to do this might be to create a new system where the divergence at the continuous level is the right hand side. Then you can repeat the usual assembly of the RHS using the loop over elems, dofs and qps, using your existing solution. You could then swap the rhs vector with one of the compon

Re: [Libmesh-users] Derivatives of shape functions at node points

2015-07-23 Thread Vikram Garg
Like Paul said, Exodus II would be the easiest way to get a visual representation of the divergence. I also need to correct what I said earlier. If you want to represent the divergence of the solution (which is in L2) in the same nodal basis as the solution, i.e. let f = div(u_h), and F = sum f_i

Re: [Libmesh-users] Derivatives of shape functions at node points

2015-07-23 Thread Paul T. Bauman
On Wed, Jul 22, 2015 at 7:13 PM, Sahai, Amal wrote: > I have a system with 3 variables, representing the x,y,z component of a > quantity. I solved this system to obtain the component wise distribution in > a given domain. I would now like to calculate the divergence of this > distribution at the

[Libmesh-users] Derivatives of shape functions at node points

2015-07-22 Thread Sahai, Amal
I have a system with 3 variables, representing the x,y,z component of a quantity. I solved this system to obtain the component wise distribution in a given domain. I would now like to calculate the divergence of this distribution at the node points and then output this along with the previous 3