Hi Praveen, On Thursday, December 21, 2017 at 3:38:21 AM UTC+1, Praveen C wrote:
> step-7 uses QGauss<dim>(3) to compute error norm. Have you tried increased > number of quadrature points ? > > > Also, what is the quadrature rule you use for assembling? > Yes, I increased the number of quadrature points both in the assemble_system and integrate_difference. That does not show obvious difference, see the figure below. I used QGauss and Qweddle quadrature rules in them. In the figure above, I tested another 1D Poisson equation, where the solution u = x^3 + 1. The definition domain is still (0, 1). I used P3 elements for the problem. The L2 error of u is showed. The error is very small from the beginning, then it increases afterwards. I think this is some kind of roundoff error, just like Luca said. Kind regards, Jie -- 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 dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
