dolfin team mailing list archive

[Johannes Ring <johannr@xxxxxxxxx>]

Hi,

If you are using the FEniCS Ubuntu packages then try to upgrade the
python-fiat package. I just uploaded the latest version (0.3.5).

Johannes

On Thu, Nov 12, 2009 at 10:43 AM,  <hheumann@xxxxxxxxxxxx> wrote:
> Hello,
>
> I upgraded my fenics-installation on ubuntu jaunty to the latest version
> and observed some problems with lowest order Nedelec elements in 3D. Since
> I was not sure, is I'm using the new Expression-Class properly I wrote
> some simple 2D test cases and it seems that already the L^2-projection for
> lowest order elements is wrong. In the attached sample code the value of
> the projection does not converge to the value of the function. If I use in
> contrast in Projection.ufl higher order Nedelec-spaces it converges.
>
> Regards,
> Holger
>
> Projection.ufl:
> W1F = FiniteElement("Nedelec 1st kind H(curl)", "triangle",0)
> vL = VectorElement("Lagrange", "triangle", 3)
>
> v = TestFunction(W1F)
> u = TrialFunction(W1F)
> f = Function(vL)
>
> a = inner(v, u)*dx
> L = inner(v,f)*dx
>
> and
>
> main.cpp:
> #include <dolfin.h>
> #include "Projection.h"
>
> using namespace dolfin;
> int main()
> {
>  class Solution : public Expression
>  {
>  public:
>  Solution() : Expression(2,2) {}
>    void eval(double* values, const double* x) const
>    {
>      values[0] = 1;
>      values[1] = 0; //sin(DOLFIN_PI*x[0]);
>    }
>  };
>  UnitSquare mesh(2,2);
>  Solution solution;
>  for (unsigned int i=0; i<6; i++)
>  {
>          mesh.refine();
>          Projection::FunctionSpace VP(mesh);
>          Projection::BilinearForm m(VP,VP);
>          Projection::LinearForm LP(VP);
>          LP.f = solution;
>          VariationalProblem problemP(m,LP);
>          Function T(VP);
>          problemP.solve(T);
>          double x[2] = {0.123, 0.23441};
>          // Evaluate user-defined function f
>          double value[2] = {0.1,0.1};
>          solution.eval(&(value[0]), x);
>          info("exact value f(x) = (%g,%g)", value[0],value[1]);
>          // Evaluate discrete function g (projection of f)
>          double value2[2] = {0.1,0.1};
>          T.eval(&(value2[0]), x);
>          info("value of projection g(x) = (%g,%g)", value2[0],value2[1]);
>  }
>  return 0;}
>
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