what’s the meaning of u.x.array if u is a solution of equation?And,if there’s any function which is similar to the compute_vertex_values function and capable to calculate the solution values on mesh nodes.

In every finite element implementation, one works with degrees of freedom, i.e. unknown coefficients that one would like to solve an equation for,

Some notes about this can be found at:

https://scientificcomputing.github.io/mpi-tutorial/notebooks/dolfinx_MPI_tutorial.html#dolfinx-functions

See: How to get vertex values in dolfinx? - #17 by nav

which recommends interpolating into a first order Lagrange space (as that is what was done under the hood in `compute_vertex_values`

, as shown in

Mapping of results to mesh nodes, debugging of dolfinx implentation of shell formulation - #6 by dokken

for facets:

Extract the coordinates of the boundary points and the value of a function on them - #4 by dokken

thanking for your quick reply! I’m new to dolfinx, how to implement the “uh.compute_vertex_values(mesh) in old fenics” in dolfinx v0.6.0 for a simple poisson equation.here mesh is a 10*10 square mesh.

I want to get the mesh coordinates which ordering is from left to right and from bottom to top, and the values in mesh points have the same ordering as mesh coordinates

Please read the posts that I’ve already posted, as

explains this.

thanks for your reply,i will carefully read the posts you recommended