🌟 MFEM 4.9 Released

[tzanio]

Dear MFEM community,

Version 4.9 of MFEM was released on December 11, 2025. Highlights of this release include:

• Starting with this version, MFEM requires a C++17 compiler.

• Introducing ∂FEM: a new MFEM capability for Automatic Differentiation (AD) of nonlinear finite element operators, based on Enzyme or dual numbers AD at quadrature points. These features are part of the new mfem::future namespace. See the new fem/dfem/ directory and the minimal surface miniapp for illustration of ∂FEM's use.

• Initial support for particle methods in MFEM with new classes Particle, ParticleSet and ParticleVector. See the new particle miniapps in miniapps/gslib and miniapps/fluids/navier.

  • Transient Navier-Stokes fluid-particles solver NavierParticles in miniapps/fluids/navier/navier_particles, for modeling tracer particles in fluid flow, demonstrating use of the new ParticleSet class.
  • Navier bifurcation miniapp in miniapps/fluids/navier/navier_bifurcation, showing the use of NavierParticles in a 2D bifurcating channel flow.
  • Particle redistribution FindPointsGSLIB miniapp in miniapps/gslib/particles_redist, showing parallel-redistribution of particle data between MPI ranks.
  • Particle visualization features in miniapps/common/particles_extras for viewing article locations and trajectories (ParticleTrajectories) using GLVis.

• Added a new miniapp and specialized AMGF solver for optimization-based contact mechanics. The miniapp solves large-scale frictionless contact using aself-contained Interior Point (IP) solver, mortar-based contact constraints provided by Tribol. For more details, see the miniapps/contact directory.

• Added a method to compute piecewise linear bounds on high-order functions on tensor-product elements. See the new mesh-bounding-boxes and gridfunction-bounds miniapps.

• Added support for boundary integration to the hyperbolic framework. Two new classes BdrHyperbolicDirichletIntegrator and BoundaryHyperbolicFlowIntegrator have been introduced for implementation of weak Dirichlet boundary conditions with a general flux or for the linear case respectively.

• Introduced IMEX ODE solvers based on a split-operator framework. Added examples ex41 and ex41p demonstrating IMEX DG/CG discretizations of the convection–diffusion equation, with ex41p using DG LOR preconditioning.

• The TMOP kernel hierarchy has been restructured to reduce compilation time. Most large kernels have been split into smaller specific kernels for each metric. The directory structure has been updated with assemble, metrics, mult and tools subdirectories.

• Introduced NC-patch NURBS meshes, which are conforming element-wise but allow for nonconforming patch topology. This new mesh format supports element spacing formulas for refinement, as well as local refinement factors for a subset of knot vectors.

• Added a new miniapp for interpolating a surface grid of points in 3D using a smooth NURBS surface, that can then be sampled at arbitrary resolution while staying close to the original geometry. See miniapps/nurbs/nurbs_surface.

• Parallel anisotropic refinement of hexahedral meshes is now supported, provided that neighboring hexahedra are not refined in conflicting directions. A new ParMesh method is added to check for such conflicts, before refinement.

• Added the option to enable GPU-aware MPI in MFEM using the environment variable MFEM_GPU_AWARE_MPI set to any value. Setting this environment variable is an alternative to calling Device::SetGPUAwareMPI(true).

• Introduced MFEM_FOREACH_THREAD_DIRECT, which directly maps loop tasks to GPU threads, assigning one task per thread.

• Added the miniapps/fluids directory and moved the previous Navier and the new incompressible Schrödinger flow miniapps into it.

• Added a new miniapp, Lorentz, which computes the trajectory of a charged particle, subject to Lorentz forces, in electrostatic and/or magnetostatic fields as computed by the Volta or Tesla miniapps.

• Added miniapps to demonstrate an implementation of the absolute-value l1-Jacobi preconditioners in partially assembled operators. This includes Multigrid wrapper to demonstrate the effectiveness of these Jacobi-type operators as smoothers. See the miniapps/diag-smoothers directory.

• Many other improvements, including:

  • New MFEM_FETCH_TPLS CMake option to enable downloading, configuring, and building of third-party libraries alongside MFEM (currently supported are: hypre, METIS, and GSLIB).
  • Quadrature function support to the VisIt and Conduit data collections.
  • Updated mtop miniapp with GPU-enabled forward and adjoint solver for isotropic linear elasticity.
  • Variational resampling of H1 vector fields in the ParMoonolith integration.
  • Interior face integration for DG in ParMixedBilinearForm, ParNonlinearForm and ParBlockNonlinearForm.
  • Support for higher order meshes in (Par)Mesh::MakeSimplicial.
  • ...and more!

To download the release and for more information, visit https://mfem.org.

We welcome your feedback at https://github.com/mfem/mfem/issues.

—The MFEM team

cc: @mfem/everyone

[alexmyczko]

https://ftp-master.debian.org/new/mfem_4.9%2Bds-1.html -> https://tracker.debian.org/pkg/mfem

[topazus]

https://bodhi.fedoraproject.org/updates/FEDORA-2025-6928f579c1

[barracuda156]

macos-powerpc/powerpc-ports@f9f5bc4