On 6/9/23 08:27, Mathieu wrote:
Say, P=(Px,Py) is the point outside the domain,
T=(Tx, Tx) the closest vertex at the boundary as computed above,
and grad_T the gradient of the finite element function at T.
Then I would compute the function value at P as
f(P) = f(T) + grad_T[0]*(Px-Tx) + grad_T[1]*(Py-Ty).
Is that reasonable?
Yes, that is just a linear extrapolation and that's reasonable if your
solution is smooth and if P is close to T.
If T is a vertex, then the solution generally has a kink there and the
gradient can have several values depending on which adjacent cell you take it
on. Whether that matters to you is a separate question -- it may be sufficient
to simply take the gradient from one of the adjacent cells.
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/
--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see
https://groups.google.com/d/forum/dealii?hl=en
---
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to dealii+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/dealii/dcf478b6-5810-4fcf-e174-1f7ed33050f5%40colostate.edu.
