Consider the short MWE : import ufl import dolfinx as dfx from dolfinx.io import XDMFFile from mpi4py.MPI import COMM_WORLD with XDMFFile(COMM_WORLD, "mesh.xdmf", "r") as file: mesh = file.read_mesh(name="Grid") FE=ufl.FiniteElement("Lagrange",mesh.ufl_cell(),1) V = dfx.FunctionSpace(mesh,FE)…

The problem is that the interior cells in your mesh are not connected. This can be illustrated by running the following: import ufl import dolfinx as dfx from dolfinx.io import XDMFFile from mpi4py.MPI import COMM_WORLD import numpy as np from petsc4py import PETSc with XDMFFile(COMM_WORLD, "mesh.…

I’m trying with the identity now. Having n=ufl.inner(u,v)*ufl.dx gives another ugly graph : [ugly2] I don’t understand why this graph isn’t filled with red throughout and why there appears to be some sort of scar of zeros at a random position… I’m in complex mode, running sequentially my docker …

Many thanks for your quick response ; I can’t seem to get your code running on my machine though. I had to rollback a few of the synthax, I’m standing on : import ufl import dolfinx as dfx from dolfinx.io import XDMFFile from mpi4py.MPI import COMM_WORLD import numpy as np with XDMFFile(COMM_WORLD…

Just remove V from [image] hawkspar: bc = dfx.DirichletBC(c, dofs, V) i.e. bc = dfx.DirichletBC(c, dofs). [image] hawkspar: Do you think this mesh break up can be fixed inside dolfinx or would it be easier to start anew ? The mesh break up should be fixed in the mesh generator, sti…

Ok thanks I’ll try to read a fresh mesh again. Do you expect it to solve both the “scar” and the values problem ? Looking at the first figure, I can see how the problem you’re mentioning breaks specific regions of the graph, but not why my r^2 is not looking like a square…

I would suggest starting by checking that interpolating or projecting r^2 into a suitable function space gives the expected function. In general, if something works on the unit square or a rectangle mesh, it should work on any mesh.

Trivial form fails on xdmf mesh

hawkspar May 20, 2022, 12:07pm 3

I’m pretty sure this problem is unrelated to this one since in my version of dolfinx dolfinx.fem.form is still a module.

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Trivial form fails on xdmf mesh

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