# dolfinx **URL:** https://fenicsproject.discourse.group/c/dolfinx/12.md [Latest](https://fenicsproject.discourse.group/latest.md) · [Categories](https://fenicsproject.discourse.group/categories.md) · [Tags](https://fenicsproject.discourse.group/tags.md) --- ## [About the dolfinx category](https://fenicsproject.discourse.group/t/about-the-dolfinx-category/3467)
**Author:** [@jackhale](https://fenicsproject.discourse.group/u/jackhale)\ **Replies:** 0
This category is related to questions regarding the recommended and maintained version of DOLFIN, called DOLFINx. The difference between dolfin and DOLFINx is sketched in the FEniCS-roadmap. --- ## [Integrating over a boundary surface in DolfinX 0.11](https://fenicsproject.discourse.group/t/integrating-over-a-boundary-surface-in-dolfinx-0-11/19839)
**Author:** [@BillS](https://fenicsproject.discourse.group/u/BillS)\ **Replies:** 2\ **Last updated:** [October 23, 2026, 5:32pm UTC](https://fenicsproject.discourse.group/t/integrating-over-a-boundary-surface-in-dolfinx-0-11/19839 "2026-10-23T17:32:28Z")
In using the “allreduce” statement to generate an integral over a boundary surface that computes the surface area of a boundary, something seems to have changed in the way this is done. (It works in DolfinX 0.9.0.) The … --- ## [Fenicsx - Complex Numbers](https://fenicsproject.discourse.group/t/fenicsx-complex-numbers/17806)
**Author:** [@Methmika\_Jayawardene](https://fenicsproject.discourse.group/u/Methmika_Jayawardene)\ **Replies:** 6\ **Last updated:** [October 21, 2026, 5:10pm UTC](https://fenicsproject.discourse.group/t/fenicsx-complex-numbers/17806 "2026-10-21T17:10:10Z")
Hello guys, I am new to Fenicsx and I am testing examples to understand how Fenicsx works before using it for my projects. I installed fenicsx following the Nguyen Lab Wiki - fenicsx – Nguyen Lab Wiki On windows, usin… --- ## [BC application when using non linear solver (dolfinx\_mpc)](https://fenicsproject.discourse.group/t/bc-application-when-using-non-linear-solver-dolfinx-mpc/18431)
**Author:** [@gianmon99](https://fenicsproject.discourse.group/u/gianmon99)\ **Replies:** 4\ **Last updated:** [October 11, 2026, 6:23am UTC](https://fenicsproject.discourse.group/t/bc-application-when-using-non-linear-solver-dolfinx-mpc/18431 "2026-10-11T06:23:59Z")
I’m trying to implement a RANS simulation on a periodic hill (using the k-epsilon turbulence model) However it seems like I’m unable to apply the BC to the speed ad the pressure when I’m using the NonLinear solver of do… --- ## [Mass matrix between non matching meshes](https://fenicsproject.discourse.group/t/mass-matrix-between-non-matching-meshes/19835)
**Author:** [@JanvdW](https://fenicsproject.discourse.group/u/JanvdW)\ **Replies:** 1\ **Last updated:** [September 29, 2026, 3:14am UTC](https://fenicsproject.discourse.group/t/mass-matrix-between-non-matching-meshes/19835 "2026-09-29T03:14:26Z")
Hi, I have the following setup. I have two finite element spaces, T\_h and T\_H. The mesh of T\_h is a true refinement of the mesh of T\_H. Also, T\_h uses a cg Lagrange basis of degree one, while T\_H uses a dg Legendre basi… --- ## [Incorrect PETSc.Mat block size when using enriched\_element](https://fenicsproject.discourse.group/t/incorrect-petsc-mat-block-size-when-using-enriched-element/19805)
**Author:** [@TimS](https://fenicsproject.discourse.group/u/TimS)\ **Replies:** 1\ **Last updated:** [September 22, 2026, 2:02pm UTC](https://fenicsproject.discourse.group/t/incorrect-petsc-mat-block-size-when-using-enriched-element/19805 "2026-09-22T14:02:13Z")
General info (even though I do not think it matters much): MacOS 26.6.1 Python 3.14.6 (conda) fenics-dolfinx 0.11.0 (conda) petsc4py 3.25.4 (conda) In my application, I am using the MINI element (P1 Lagrange enriched … --- ## [Sector periodicity for rotating domains](https://fenicsproject.discourse.group/t/sector-periodicity-for-rotating-domains/19826)
**Author:** [@sbhasan](https://fenicsproject.discourse.group/u/sbhasan)\ **Replies:** 4\ **Last updated:** [September 18, 2026, 2:27am UTC](https://fenicsproject.discourse.group/t/sector-periodicity-for-rotating-domains/19826 "2026-09-18T02:27:52Z")
I am considering a rotating electric machine which is efficiently solved for periodic sectors specially in 3D. Below is an exemplary image to convey the idea: I was wondering whether we have tools in dolfinx that cou… --- ## [Distortion driven remeshing in DOLFINx](https://fenicsproject.discourse.group/t/distortion-driven-remeshing-in-dolfinx/19824)
**Author:** [@kumar](https://fenicsproject.discourse.group/u/kumar)\ **Replies:** 3\ **Last updated:** [September 14, 2026, 2:41pm UTC](https://fenicsproject.discourse.group/t/distortion-driven-remeshing-in-dolfinx/19824 "2026-09-14T14:41:35Z")
Dear all, I am planning to work on a large deformation problem in dolfinx 0.10.0 where the mesh will get distorted over time. I would like to detect when cell quality drops below a threshold, remesh the deformed domain,… --- ## [Elasto-plastic contact support in dolfinx-contact](https://fenicsproject.discourse.group/t/elasto-plastic-contact-support-in-dolfinx-contact/19796)
**Author:** [@kumar](https://fenicsproject.discourse.group/u/kumar)\ **Replies:** 1\ **Last updated:** [September 10, 2026, 3:52pm UTC](https://fenicsproject.discourse.group/t/elasto-plastic-contact-support-in-dolfinx-contact/19796 "2026-09-10T15:52:11Z")
Dear all, I am using the dolfinx-contact library for a mechanical contact problem: https://github.com/Wells-Group/asimov-contact The library provides well-developed contact detection and Nitsche-based contact formulat… --- ## [Real-space Lagrange multiplier constraint silently violated (non-deterministically) when a periodic MPC slave/master pair spans different MPI ranks — reproducible on v0.10.5 and v0.11.0](https://fenicsproject.discourse.group/t/real-space-lagrange-multiplier-constraint-silently-violated-non-deterministically-when-a-periodic-mpc-slave-master-pair-spans-different-mpi-ranks-reproducible-on-v0-10-5-and-v0-11-0/19804)
**Author:** [@czolesi1](https://fenicsproject.discourse.group/u/czolesi1)\ **Replies:** 5\ **Last updated:** [August 21, 2026, 6:58pm UTC](https://fenicsproject.discourse.group/t/real-space-lagrange-multiplier-constraint-silently-violated-non-deterministically-when-a-periodic-mpc-slave-master-pair-spans-different-mpi-ranks-reproducible-on-v0-10-5-and-v0-11-0/19804 "2026-08-21T18:58:08Z")
I’m solving a periodic elasticity/Poisson-type problem where the periodic fluctuation field v (in a MultiPointConstraint-constrained space V) has its mean pinned to zero via a scalar Lagrange multiplier gamma living in a… --- ## [ImportError on calling dolfinx.fem.form](https://fenicsproject.discourse.group/t/importerror-on-calling-dolfinx-fem-form/19792)
**Author:** [@William\_Graham](https://fenicsproject.discourse.group/u/William_Graham)\ **Replies:** 10\ **Last updated:** [August 11, 2026, 7:35am UTC](https://fenicsproject.discourse.group/t/importerror-on-calling-dolfinx-fem-form/19792 "2026-08-11T07:35:47Z")
I’m trying to solve a complex eigenvalue problem. I’ve installed anaconda using homebrew, and created an environment with conda create -n fenicsx-cmplx-env -c conda-forge fenics-dolfinx "petsc==complex" "petsc4py==compl… --- ## [Coupled problem with codim 1 submesh wrong derivative](https://fenicsproject.discourse.group/t/coupled-problem-with-codim-1-submesh-wrong-derivative/19688)
**Author:** [@RemDelaporteMathurin](https://fenicsproject.discourse.group/u/RemDelaporteMathurin)\ **Replies:** 6\ **Last updated:** [July 29, 2026, 3:25am UTC](https://fenicsproject.discourse.group/t/coupled-problem-with-codim-1-submesh-wrong-derivative/19688 "2026-07-29T03:25:59Z")
Hi all, I’m trying to solve the following problem where \\Omega is a 2D domain and \\Gamma\_1 is a 1D submesh (bottom boundary). The governing equation on \\Omega is diffusion with coupling term J and the governing equatio… --- ## [Mixing dolfinx\_mpc and scifem packages](https://fenicsproject.discourse.group/t/mixing-dolfinx-mpc-and-scifem-packages/18310)
**Author:** [@Ergonsa](https://fenicsproject.discourse.group/u/Ergonsa)\ **Replies:** 4\ **Last updated:** [July 20, 2026, 5:06pm UTC](https://fenicsproject.discourse.group/t/mixing-dolfinx-mpc-and-scifem-packages/18310 "2026-07-20T17:06:29Z")
Hello everyone, after the announcement of dolfinx v0.10.0, I decided to retake the issue of Mixing dolfinx\_mpc and scifem packages for a nonlinear problem in which I tried to solve an homogenisation problem, i.e., with p… --- ## [NewtonSolver in v11](https://fenicsproject.discourse.group/t/newtonsolver-in-v11/19778)
**Author:** [@lclaire](https://fenicsproject.discourse.group/u/lclaire)\ **Replies:** 2\ **Last updated:** [July 20, 2026, 1:51pm UTC](https://fenicsproject.discourse.group/t/newtonsolver-in-v11/19778 "2026-07-20T13:51:13Z")
Hello, I am trying to run the hyperelasticity demo from Hyperelasticity — Computational Mechanics Numerical Tours with FEniCSx , but I get the following error message, related to NewtonSolver in NonlinearProblem: Traceb… --- ## [AV formulation with fieldsplit Hypre AMS](https://fenicsproject.discourse.group/t/av-formulation-with-fieldsplit-hypre-ams/19727)
**Author:** [@mattiafilips](https://fenicsproject.discourse.group/u/mattiafilips)\ **Replies:** 4\ **Last updated:** [July 20, 2026, 12:51pm UTC](https://fenicsproject.discourse.group/t/av-formulation-with-fieldsplit-hypre-ams/19727 "2026-07-20T12:51:41Z")
Hi, I am trying to solve the low frequency magnetoquasistatic equation with AV formulation with Coulomb gauge. I use Nedelec1 for A, CG1 for the scalar potential V and the lagrange multipliers used to force the A gauge.… --- ## [Projecting an expression onto a boundary submesh](https://fenicsproject.discourse.group/t/projecting-an-expression-onto-a-boundary-submesh/19772)
**Author:** [@rmsc](https://fenicsproject.discourse.group/u/rmsc)\ **Replies:** 8\ **Last updated:** [July 20, 2026, 12:09pm UTC](https://fenicsproject.discourse.group/t/projecting-an-expression-onto-a-boundary-submesh/19772 "2026-07-20T12:09:51Z")
I’m trying to do this projection as part of a post-processing step. I have a Function over the entire volume, and I want to plot an expression containing that Function on a few boundaries. I think this should illustrate… --- ## [Newton divergence in 2D nonlinear Two-Temperature Model (TTM) FEM — dolfinx + complex PETSc](https://fenicsproject.discourse.group/t/newton-divergence-in-2d-nonlinear-two-temperature-model-ttm-fem-dolfinx-complex-petsc/18191)
**Author:** [@GVourvachakis](https://fenicsproject.discourse.group/u/GVourvachakis)\ **Replies:** 2\ **Last updated:** [July 19, 2026, 7:20pm UTC](https://fenicsproject.discourse.group/t/newton-divergence-in-2d-nonlinear-two-temperature-model-ttm-fem-dolfinx-complex-petsc/18191 "2026-07-19T19:20:23Z")
Hi everyone, I am developing a FEM solution of the parabolic 2D two-temperature model (TTM) composed of a system of second-order non-linear coupled PDEs (cf. eq.5 here with an additional lattice heat flux term under Fou… --- ## [Maximum of a function from DG space](https://fenicsproject.discourse.group/t/maximum-of-a-function-from-dg-space/19777)
**Author:** [@sbhasan](https://fenicsproject.discourse.group/u/sbhasan)\ **Replies:** 4\ **Last updated:** [July 19, 2026, 3:41pm UTC](https://fenicsproject.discourse.group/t/maximum-of-a-function-from-dg-space/19777 "2026-07-19T15:41:55Z")
As the title says, I need to find the maximum of a field interpolated to functions from discontinuous galerkin space. I see some old threads where the problem was addressed for continuous functions. Is there a similar so… --- ## [UFL Conditional Breaking NonlinearProblem](https://fenicsproject.discourse.group/t/ufl-conditional-breaking-nonlinearproblem/19775)
**Author:** [@shivam](https://fenicsproject.discourse.group/u/shivam)\ **Replies:** 2\ **Last updated:** [July 16, 2026, 4:19pm UTC](https://fenicsproject.discourse.group/t/ufl-conditional-breaking-nonlinearproblem/19775 "2026-07-16T16:19:07Z")
Hey y’all. Just as a preface, I am using v 0.10 of DOLFINx. I am building a axisymmetric contact mechanics model between and analytical rigid indenter and an elastic body using a penalty method, currently using the linea… --- ## [Computing normal and tangent stress at boundary in contact problem with hyperelastic material](https://fenicsproject.discourse.group/t/computing-normal-and-tangent-stress-at-boundary-in-contact-problem-with-hyperelastic-material/19764)
**Author:** [@bpsharma](https://fenicsproject.discourse.group/u/bpsharma)\ **Replies:** 1\ **Last updated:** [July 8, 2026, 6:16pm UTC](https://fenicsproject.discourse.group/t/computing-normal-and-tangent-stress-at-boundary-in-contact-problem-with-hyperelastic-material/19764 "2026-07-08T18:16:06Z")
Hi everyone I am solving a Nitsche-based Coulomb friction contact problem in DOLFINx for a simple triangle in contact with a flat, rigid plane (y=0). I am trying to extract and verify the normal and tangential stress co… --- ## [Computing derivative of residual vector w.r.t material parameter for finite element model updating](https://fenicsproject.discourse.group/t/computing-derivative-of-residual-vector-w-r-t-material-parameter-for-finite-element-model-updating/18426)
**Author:** [@SolidMechanicsFan](https://fenicsproject.discourse.group/u/SolidMechanicsFan)\ **Replies:** 7\ **Last updated:** [July 4, 2026, 5:30pm UTC](https://fenicsproject.discourse.group/t/computing-derivative-of-residual-vector-w-r-t-material-parameter-for-finite-element-model-updating/18426 "2026-07-04T17:30:06Z")
Hi all, I am doing finite-element model updating for hyperelastic material models where I need analytic sensitivities of the residual w.r.t. constant material parameters: \\frac{\\partial \\mathbf{R}}{\\partial m} \\in \\mat… --- ## [Poisson solver with big field error](https://fenicsproject.discourse.group/t/poisson-solver-with-big-field-error/19761)
**Author:** [@wwshunan](https://fenicsproject.discourse.group/u/wwshunan)\ **Replies:** 0\ **Last updated:** [July 4, 2026, 12:32pm UTC](https://fenicsproject.discourse.group/t/poisson-solver-with-big-field-error/19761 "2026-07-04T12:32:09Z")
Hello everyone, I have a numerical model consisting of a grounded metallic outer shell enclosing a uniformly charged spherical particle distribution to solve the internal electric field. The simulated electric field res… --- ## [How to load XDMF in Dolfinx 0.9.0?](https://fenicsproject.discourse.group/t/how-to-load-xdmf-in-dolfinx-0-9-0/19760)
**Author:** [@buggyfenics](https://fenicsproject.discourse.group/u/buggyfenics)\ **Replies:** 2\ **Last updated:** [July 3, 2026, 10:32am UTC](https://fenicsproject.discourse.group/t/how-to-load-xdmf-in-dolfinx-0-9-0/19760 "2026-07-03T10:32:23Z")
I am trying to load a Fenics-generated XDMF file in Fenics. The code is: def load\_solution(xdmf\_file): with XDMFFile(MPI.COMM\_WORLD, xdmf\_file, "r") as f: mesh = f.read\_mesh() V = fem.functionspace(m… --- ## [Challenges in reproducing phase-field fracture benchmark: Unphysical crack trajectory and mesh refinement behavior](https://fenicsproject.discourse.group/t/challenges-in-reproducing-phase-field-fracture-benchmark-unphysical-crack-trajectory-and-mesh-refinement-behavior/19720)
**Author:** [@Zylora126](https://fenicsproject.discourse.group/u/Zylora126)\ **Replies:** 11\ **Last updated:** [July 1, 2026, 3:06pm UTC](https://fenicsproject.discourse.group/t/challenges-in-reproducing-phase-field-fracture-benchmark-unphysical-crack-trajectory-and-mesh-refinement-behavior/19720 "2026-07-01T15:06:57Z")
Hi, every FEniCSx uesrs. I’m implementing an adaptive phase-field fracture model in FEniCSx (dolfinx), closely following the approach in Giri et al. (2025, Finite Elements in Analysis and Design). The benchmark is a 1×1 … --- ## [Assembly of a row matrix for an integral constraint](https://fenicsproject.discourse.group/t/assembly-of-a-row-matrix-for-an-integral-constraint/19751)
**Author:** [@Javier\_Sierra](https://fenicsproject.discourse.group/u/Javier_Sierra)\ **Replies:** 1\ **Last updated:** [June 29, 2026, 1:25pm UTC](https://fenicsproject.discourse.group/t/assembly-of-a-row-matrix-for-an-integral-constraint/19751 "2026-06-29T13:25:32Z")
Dear users, I found a performance issue when assembling a row matrix A of global size (1, N). These kind of matrices arise naturally when imposing a global constraint for singular problems, see for instance, Real functi… --- ## [Prolongation matrix in dolfinx](https://fenicsproject.discourse.group/t/prolongation-matrix-in-dolfinx/19735)
**Author:** [@JanvdW](https://fenicsproject.discourse.group/u/JanvdW)\ **Replies:** 0\ **Last updated:** [June 12, 2026, 2:57pm UTC](https://fenicsproject.discourse.group/t/prolongation-matrix-in-dolfinx/19735 "2026-06-12T14:57:18Z")
Hi, I am working on implementing LOD-methods in python. For these methods I am working two 2d DG function spaces of degree 1 (a coarse and a fine space). The fine mesh is obtained via dfx.mesh.refine. I am now looking t… --- ## [Discontinuities at MPI partition boundaries with manual periodic MPC on large high-order curved mesh](https://fenicsproject.discourse.group/t/discontinuities-at-mpi-partition-boundaries-with-manual-periodic-mpc-on-large-high-order-curved-mesh/19717)
**Author:** [@Bob](https://fenicsproject.discourse.group/u/Bob)\ **Replies:** 4\ **Last updated:** [May 29, 2026, 7:54am UTC](https://fenicsproject.discourse.group/t/discontinuities-at-mpi-partition-boundaries-with-manual-periodic-mpc-on-large-high-order-curved-mesh/19717 "2026-05-29T07:54:21Z")
Hi, I’m running a Poisson problem with periodic BCs in two directions on a high-order Lagrange space, and I’m seeing discontinuities (“lightning”) in the solution that align with MPI partition boundaries. Single-rank pr… --- ## [Slope limiting for the St.Venant equations in DOLFINx](https://fenicsproject.discourse.group/t/slope-limiting-for-the-st-venant-equations-in-dolfinx/19708)
**Author:** [@Testosteronnie](https://fenicsproject.discourse.group/u/Testosteronnie)\ **Replies:** 4\ **Last updated:** [May 20, 2026, 8:22am UTC](https://fenicsproject.discourse.group/t/slope-limiting-for-the-st-venant-equations-in-dolfinx/19708 "2026-05-20T08:22:15Z")
Hi, I am currently using a RK solver to solve the ST. Venant equations for a square channel given by \\frac{\\partial A}{\\partial t}+\\frac{\\partial Q}{\\partial s}=0 and \\frac{\\partial Q}{\\partial t} + \\frac{\\partial}{\\… --- ## [Dolfinx v0.10 in spack](https://fenicsproject.discourse.group/t/dolfinx-v0-10-in-spack/19704)
**Author:** [@Iman](https://fenicsproject.discourse.group/u/Iman)\ **Replies:** 10\ **Last updated:** [May 19, 2026, 10:20am UTC](https://fenicsproject.discourse.group/t/dolfinx-v0-10-in-spack/19704 "2026-05-19T10:20:09Z")
Hi, I need to have dolfinx v0.10 in spack, but when I add “spack add py-fenics-dolfinx@0.10” and then “install”, it mentions that this version of donfinx is not in the spack. I found from “https://fenicsproject.discours… --- ## [Mixed problem with tensor function subspaces without solution](https://fenicsproject.discourse.group/t/mixed-problem-with-tensor-function-subspaces-without-solution/19710)
**Author:** [@elefant5320](https://fenicsproject.discourse.group/u/elefant5320)\ **Replies:** 0\ **Last updated:** [May 19, 2026, 8:57am UTC](https://fenicsproject.discourse.group/t/mixed-problem-with-tensor-function-subspaces-without-solution/19710 "2026-05-19T08:57:51Z")
Hello FENICSx users, I need to solve this elementary problem from strain gradient elasticity using mixed formulation \\begin{equation} \\begin{split} &\\int\_{\\Omega}\\big\[\\boldsymbol{\\sigma}:\\delta\\boldsymbol{\\varepsilon}… [Next page](https://fenicsproject.discourse.group/c/dolfinx/12.md?page=1)