I fixed the error in my code by following step-39. There was a mistake in attaching the right_hand_side to MeshWorker assembler. Now the RKDG scheme works. The solution is however oscillatory since it is discontinuous. This is true of the original step-12 code also. Some type of limiting has to be implemented. However limiters are very ad-hoc fixes and dont fit well in the FEM context, and I dont know yet how to implement them inside deal.ii
Thanks praveen PS: The latest RKDG code is here http://code.google.com/p/cfdlab/source/browse/trunk/deal.ii/step-12-RKDG/step-12.cc On Sun, Jan 30, 2011 at 8:17 PM, Praveen C <[email protected]> wrote: > Hello > > I think I understood how to pass solution to meshworker by looking at > step-39 > > For RKDG, I will be doing time iterations. The right hand side is > calculated in every time step but the MeshWorker does not change. So I put > the MeshWorker in a separate class RHSIntegrator. > > But I end up getting an error from integration_loop and seems like it is > not able to change the right_hand_side > > $ ./step-12 > DEAL::Cycle 0 > DEAL::Number of active cells: 1024 > Allocating memory ... > DEAL::Number of degrees of freedom: 4096 > Constructing mass matrix ... > Quadrature using 2 points > Solving by RK ... > Setting up mesh worker ... > -------------------------------------------------------- > An error occurred in line <341> of file > </Users/praveen/Applications/deal.II/7.0.0/include/deal.II/base/named_data.h> > in function > DATA& dealii::NamedData<DATA>::operator()(unsigned int) [with DATA = > dealii::SmartPointer<dealii::Vector<double>, > dealii::MeshWorker::Assembler::ResidualSimple<dealii::Vector<double> > >] > The violated condition was: > !is_constant > The name and call sequence of the exception was: > ExcConstantObject() > Additional Information: > (none) > > > I have not been able to find the mistake and hope somebody can help. The > code is here > > > http://code.google.com/p/cfdlab/source/browse/trunk/deal.ii/step-12-RKDG/step-12.cc?spec=svn201&r=201 > > > Thanks > praveen > >
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