Re: [Libmesh-users] FEBase object fails to calculate values

[John P. <jwp...@gm...>]

On Wed, Jun 12, 2019 at 4:38 PM Nathan Andrew Miller <
Nat...@co...> wrote:

> I'm trying to compute the xyz, JxW, and other values at arbitrary points
> for a FEBase object during the evaluation of a MOOSE UserObject. I
> implemented the following in code:
>
> ```
> //Create a vector of points
> std::vector< Point > cell_points;
>
> ...things to fill cell_points...
>
> //Create a vector of ones (the weights)
> ones = std::vector< double > (cell_points.size(), 1);
>
> std::unique_ptr< libMesh::FEBase > fe(
> libMesh::FEBase::build(_mesh.dimension(),
> libMesh::FEType(_current_elem->default_order())));
>
> fe->reinit(_current_elem, &cell_points, &ones);
>
>
You have to pre-request that the xyz values be computed before you call
fe->reinit. So put the following line:


> std::vector< Point > xyz = fe->get_xyz();
>

before the reinit() call and it should work.

--
John