From A.Z.Candelaria at sms.ed.ac.uk Fri Sep 11 10:12:23 2026 From: A.Z.Candelaria at sms.ed.ac.uk (Zac Candelaria) Date: Fri, 11 Sep 2026 08:12:23 -0000 Subject: [dune-fem] Periodic Boundary Conditions Message-ID: Hi, My name is Zac, I'm trying to use the Dune Python API (dune-fempy, I believe) to solve a PDE on the unit square in which I have periodic boundary conditions on the left and right. I saw that one of the methods for creating a mesh explicitly takes a "periodic" keyword argument - however, using the following >from dune.grid import cartesianDomain, yaspGrid > ># periodic=[0] makes the x-direction periodic; [0,1] makes both x and y periodic >domain = cartesianDomain([0, 0], [L_x, L_y], [nx, ny], periodic=[True, False]) >mesh = yaspGrid(domain) gives the following error message: >Traceback (most recent call last): > > File ~/dune-env/lib/python3.12/site-packages/spyder_kernels/py3compat.py:356 in compat_exec > exec(code, globals, locals) > > File ~/duneFempyExamples/untitled0.py:305 > collSolver = scipy.sparse.linalg.factorized(sysMatCollNumpy) > > File ~/dune-env/lib/python3.12/site-packages/scipy/sparse/linalg/_dsolve/linsolve.py:653 in factorized > return splu(A).solve > > File ~/dune-env/lib/python3.12/site-packages/scipy/sparse/linalg/_dsolve/linsolve.py:444 in splu > return _superlu.gstrf(N, A.nnz, A.data, indices, indptr, > >RuntimeError: Factor is exactly singular Is there a different way to implement PBCs? Best wishes, Zac The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. Is e buidheann carthannais a th' ann an Oilthigh Dhùn Èideann, clàraichte an Alba, àireamh clàraidh SC005336. -------------- next part -------------- An HTML attachment was scrubbed... URL: