Oh, thanks! That happens if I start from an example, and don't write everything from scratch...
Am Donnerstag, 4. April 2019 12:25:10 UTC+2 schrieb Martin Kronbichler: > > Dear Maxi, > > The problem is the quadrature formula you use in 'assemble_system' and > 'calculate_residual'. You should use 'QGauss<dim> > quadrature_formula(fe.degree+1)`. I am surprised that quadratic elements > even worked because the Poisson matrix for d>=2 should have some rank > deficiency with under-integration as far as I know. > > Best, > Martin > On 04.04.19 11:31, 'Maxi Miller' via deal.II User Group wrote: > > I wrote a test program, based on step-5, for testing unrelated things, and > checked the results. But when I increased the degree of the finite elements > from 1 to 3 (or higher), the results were wrong, while the change from 1 to > 2 just improved convergence, as expected. Did I make a mistake in my code > here? > -- > 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] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > > -- 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]. For more options, visit https://groups.google.com/d/optout.
