Hi Mike,
I think this (using QTrap with TRI3SUBDIVISION elements) should work just
fine. Did you try it yet? Let us know and we can update the case statements
for quadrature. There are many places like this in the library where TRI3
and TRI3SUBDIVISION elements can be used more or less interchangeably, so
there's probably a bunch we haven't found yet.
--
John
On Wed, Aug 28, 2019 at 12:33 AM Lee, Jae Ho <jaeho...@live.unc.edu> wrote:
> Hello,
>
> I am currently implementing something that makes use of TRI3SUBDIVISION
> elements, and one of the initial things that I want to do is to compute the
> nodal coordinates for each deformed element. I am trying to avoid the use
> of MeshFunction to do this. Of course since subdivision shape functions are
> not interpolatory, I can’t just use the solution of the coordinate system
> directly as the coordinates of the element vertices. So what I am trying to
> use QTrap that uses nodal quadrature points and evaluating the shape
> functions at the quadrature points for a given element to get something like
>
> std::unique_ptr<libMesh::FEBase> fe(libMesh::FEBase::build(2,
> libMesh::SUBDIVISION));
> std::unique_ptr<libMesh::QBase> qrule =
> libMesh::QBase::build(libMesh::QTRAP, 2, libMesh::FIRST);
> fe->attach_quadrature_rule(qrule.get());
> fe->reinit(elem);
> for (unsigned int qp = 0; qp < qrule->n_points(); ++qp)
> {
> for (unsigned int d = 0; d < 3; ++d)
> {
> for (unsigned int i = 0; i < phi.size(); ++i)
> {
> X_node[qp][d] += X_solution[i][d] * phi[i][qp];
> }
> }
> }
>
> X_solution is where the solution of the coordinate system has been stored.
>
> Does this seem reasonable?
> But quadrature_trap_2D.C complained because TRI3SUBDIVISION is not
> supported. Is it safe to hardcode TRI3SUBDIVISION as a case in the code? Or
> is there a different way to go about it (e.g. is there a different nodal
> quadrature rule that supports TRI3SUBDIVISION)?
>
> Thank you,
> Mike
>
>
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