Hello! I’m using dolfinx 0.8.0 and I need to solve 3 problems. Say I solve u on mesh1 and v on mesh2 and that both domains share a side \Gamma. Now I want to solve a third problem on mesh2, using as Neumann data on \Gamma the difference between u and v. How can I do that? because I have the feel…

Consider the minimal working example: from mpi4py import MPI import dolfinx import numpy as np L = 1 N = 5 def interface(x): return np.isclose(x[0], L) mesh_1 = dolfinx.mesh.create_box( comm=MPI.COMM_WORLD, points=[(0, 0, 0), (L, L, L)], n=[N, N, N] ) V = dolfinx.fem.functionspace(mesh…

Could you make a sketch of your domain, clarifying if: the boundaries are conforming, ie the facets on domain 1 align with the facets of domain 2? Add your minimal attempt at solving this problem. One could for instance simply interpolate some know data into a function on mesh 1, and say that one…

The meshes are not conformanto on \Gamma since they are created separately by two calls to gmsh python addBox. One of them is simply a box so it could be entirely meshed in dolfinx, but the other one is not. Taking that into account is it still possible to do it in 0.8.0 or may be I should export …

I would use non-matching interpolation with the restriction of cells close to the boundary, which you can get with dolfinx.mesh.compute_incident_entities(mesh, bndry_facets, mesh.topology.dim-1, mesh.topology.dim)

Hi, thank you for the answer but I’m not sure if I understood how to use the return of compute_incident_entities. This would be the main non-working example: from dolfinx.mesh import create_box from dolfinx.mesh import locate_entities, meshtags from mpi4py import MPI import numpy as np L = 1 N …

Thank you very much for the example. I don’t have a VTX reader in paraview so I tried changing your code: with dolfinx.io.VTXWriter(mesh_1.comm, "u_1.bp", [u]) as bp: bp.write(0.0) with dolfinx.io.VTXWriter(mesh_2.comm, "u_2.bp", [u2]) as bp: bp.write(0.0) with from dolfinx.io import XD…

Forget it, I understood that it was a problem of XDMF with (“Lagrange”,2) elements. I changed it for (“Lagrange”,1) and it works fine. Thank you very much!

You should also be able to use VTKFile with second order Lagrange;)

Interpolate on boundary

General

MPenaR September 27, 2024, 2:36pm 6

I tried to strip the “example” from everything that is not relevant and now it looks as a domain decomposition problem. It is not.

Topic		Replies	Views
Interpolation on non-matching meshes dolfinx	13	1818	February 16, 2023
Interpolation between non-matching mesh boundaries mesh	2	305	November 13, 2023
Create nonmatching meshes interpolation data gives cryptic error. Whats wrong? dolfinx interpolation	3	446	April 16, 2024
Interpolating between meshes - Python Binding General	15	1476	April 17, 2023
Runtime error when interpolating between non-matching meshes with dolfinx update dolfinx	2	447	September 27, 2023

Interpolate on boundary

Related topics