I need to compute derivatives of a vector field at arbitrary points. First-order derivatives are nicely provided by FEFieldFunction::vector_gradient.
In order to get second-order derivatives I compute gradients at all nodes and then provide them (one component at time) to the FEFieldFunction constructor as a new data_vector. Then I use FEFieldFunction::vector_gradient again. Now I need to compute third-order derivatives also... Is there a less cumbersome way for doing this? Thanks, Luca P.S. I'm using Lagrange elements of adequate polynomial degree in order to ensure the existence of n-th order derivatives. _______________________________________________
