How to use same vector-valued mathematical expressions with both ufl and numpy?

[dokken]

For point evaluation, you need to specify what cell the point is in, as specified in: Implementation — FEniCSx tutorial

One can of course go through dolfinx.fem.Expression for more advanced code, such as shown in: Evaluation of UFL expression at mesh points - #2 by dokken and subsequent posts.

Other similar resources:

Point Sources (Redux)

Following my post above, with a minor adaptations, a point source can be implemented as follows: # Create a point source for Poisson problem # Author: Jørgen S. Dokken # SPDX-License-Identifier: MIT from mpi4py import MPI from petsc4py import PETSc import dolfinx import dolfinx.fem.petsc import numpy as np import ufl def compute_cell_contributions(V, points): # Determine what process owns a point and what cells it lies within mesh = V.mesh _, _, owning_points, cells = dolfinx.cp…

Evaluate_basis_all in dolfinx

The DOLFINx way to do this would be to: Figure out which cell the point x is in (using dolfinx.compute_colliding_cells, as done in: Implementation — FEniCSx tutorial) Pull these coordinates back to the reference element, using mesh.geometry.cmap.pull_back (dolfinx/fem.cpp at 48ece0087588f5f274a36aec223abb129fa59e8e · FEniCS/dolfinx · GitHub) Use basix.FiniteElement(element_of choice).tabulate(1, X_ref) to tabulate at the reference points. An example of the last step can be found in: asimov-cu…