> In my case I solve a simple laplace problem, that represent groundwater flow > with non zero dirichlet boundary conditions > My goal is to estimate how much water comes in and out from the dirichlet BC > nodes.
You're asking the wrong question. What you are looking for is a *flux*, which is an integral over part of the boundary. That's how you should compute it -- which implies you'll want to use FEFaceValues as always when face integrals are involved. Specifically, the flux through a single point is of course zero. > The way I could do this, is after I solve the reduced version of the full > linear system A*U = F > to calculate > DBC = A*U-F I'm not clear what you're trying to do here, but if A*U=F, then DBC is of course zero. I suspect that you mean for either A, U, or F to be something slightly different than what you had in the linear system above, but it's not clear to me -- though it may also not matter in view of what I mentioned above :-) Best W. -- ------------------------------------------------------------------------ Wolfgang Bangerth email: [email protected] www: http://www.math.colostate.edu/~bangerth/ -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/1abaa9aa-1464-28e0-22fc-56d5e379fa4e%40colostate.edu.
