Differentiable operator and outputting Q-vector

[lindsayad]

The motivating issue for this discussion is idaholab/moose#31981. Instead of performing the full $A = P^T\mathcal{E}^T B^T DB\mathcal{E}P$, is it possible to incompletely apply the operator $DB\mathcal{E} P$ in order to output a Q-vector?

(@hugary1995)

[jandrej]

Yup. The Identity FieldOperator will do that for you. It outputs whatever comes out of your Q-function for each quadrature point.

[lindsayad]

Thanks for the rapid reply!

[jandrej]

I just had time to read the related link in your original post. When #5115 is merged, this will all be done automagically for you.

[lindsayad]

That's awesome