[QUESTION] Evaluating fields at other triangle nodes during nodal assembly in `fem.integrate`

Hi,

I'm integrating over a triangle mesh using fem.integrate with assembly='nodal'. My integrand evaluates the trial field u at the sample point s, which corresponds to a specific node i of a triangle with nodes (i, j, k).

Is there a way to evaluate the same or any other field at the other two nodes of the triangle — i.e., compute sample points corresponding to nodes j and k, so I can evaluate u(s_j) and u(s_k) from within the integrand?

This would allow me to compute expressions that involve not only u(s) at the current node, but also u at neighbouring nodes of the same element.

Thanks,
Chris