2026.10.0

What's Changed

Solvers and preconditioners

• ASMStar: enable patch coloring by @pbrubeck in #4912
• Add support for objective function in SNES by @stefanozampini in #5155
• Adaptive NonlinearVariationalSolver support via -snes_adapt_sequence by @pbrubeck in #5213
• Mesh Adaptivity via DMPlexTransform by @pbrubeck in #5215
• Fix coarse-to-fine cell maps for hierarchies built on an adaptively refined mesh by @pbrubeck in #5321
• Rework PMGBase.coarsen() and add NonlinearVariationalProblem.rediscretise() by @pbrubeck in #5324
• p-multigrid: remove custom interpolation code by @pbrubeck in #5289
• Let PCASM refresh its own submatrices by @pbrubeck in #5403
• Drop the MatIS special case in FunctionSpace.local_to_global_map by @pbrubeck in #5437
• Extruded Periodic MeshHierarchy by @pbrubeck in #4663
• Stop DG injection reading past a coarse cell's children by @pbrubeck in #5337
• MeshHierarchy: assemble prolongation into MatAIJ by @pbrubeck in #5206
• Multigrid: derive hierarchy maps from DMPlex transforms by @pbrubeck in #5460

Point location/VertexOnlyMesh

• Use firedrake-rtree for spatial indexing by @leo-collins in #4981
• New plotting methods for VertexOnlyMesh by @achanbour in #5039
• Use mat context for Vom onto vom matfree interpolation by @leo-collins in #5055
• Assembly of matfree interpolation operator by @leo-collins in #4778
• Write VOM data to VTKFile by @achanbour in #5244
• Access DMSwarm fields via a context manager by @leo-collins in #5296
• rtree bulk query by @leo-collins in #5247

Finite elements

• Interpolation into EnrichedElement by @pbrubeck in #5184
• Support physical_normals on manifolds by @pbrubeck in #4994

GPU

• GPU offloading preconditioner by @dsroberts in #4953
• Offload Nullspaces with OffloadPC by @dsroberts in #5462
• Add AMD compatibility for OffloadPC by @dsroberts in #5220
• Minor updates to OffloadPC by @dsroberts in #5164

Form compiler

• Contract quadrature reductions in loop nest order by @pbrubeck in #5354
• tsfc: cancel Jacobian products and reciprocal factors by @pbrubeck in #5230
• Test interpolation of products of coefficient evaluations by @pbrubeck in #5360
• Compile interpolation through the GEM optimisation pipeline by @pbrubeck in #5381
• Make SLATE subclass BaseForm by @pbrubeck in #4093

Bugfixes

• move PointNotInDomainError by @leo-collins in #5041
• Refactor PCPatch code to not use PyOP2 by @connorjward in #4993
• Improve building compiled extensions using Makefile by @connorjward in #5059
• Keep a consistent labeling of boundaries for 2D periodic meshes by @connorjward in #5005
• Adjoint + submesh by @KarsKnook in #5081
• Remove add, sub magic methods from matrix by @leo-collins in #5145
• Drop support for python 3.10 by @francesco-ballarin in #5173
• Remove (very) deprecated Matrix.assemble by @connorjward in #5143
• Fix for ufl2unicode rewrite by @connorjward in #5058
• cache visible_ranks on topology by @leo-collins in #5183
• Fix Jp + multigrid by @pbrubeck in #5189
• Fix solver options for Real space by @connorjward in #5144
• DumbCheckpoint renew warning by @Ig-dolci in #5228
• Cache mesh bounding boxes correctly by @leo-collins in #5180
• Remove old PyOP2 documentation by @connorjward in #5262
• dmcommon: de-Python-ify mesh-topology construction (~4x faster BoxMesh build) by @miguelcoolchips in #5231
• Don't import interpolate from future by @connorjward in #5269
• Leo/deprecate clear rtree by @leo-collins in #5315
• fix rpaths for macos by @leo-collins in #5301
• Remove dead code by @achanbour in #5320
• interpolator init cleanup by @leo-collins in #5319
• Fix quadratic cost in adaptive mesh refinement's coarse/fine cell-map construction by @pbrubeck in #5326
• Fix broken test with exact comparisons by @pbrubeck in #5353
• Make serial submesh construction linear in the number of points by @haldaas in #5349
• Lint cython code by @stefanozampini in #5363
• Fix cython linting by @connorjward in #5366
• tinyasm: avoid copying the block dofmap in BlockJacobi::solve() by @manishpaulish in #5348
• Check that equivalent cells compile a form the same way by @pbrubeck in #5375
• Use correct dtype during PCPatch codegen by @connorjward in #5395
• Unified cache under sys.prefix by @pbrubeck in #5400
• Remove backwards compat tests for variable layer extrusion by @connorjward in #5418
• autoregressive covariance operator: fix scaling for dim>1 by @JHopeCollins in #5358
• Replace :: with codeblocks in demos by @nwng04 in #5414
• Make the Stokes multigrid appctx test deterministic by @pbrubeck in #5453
• Fix NumPy 2.5 deprecation warning in pyop2.utils.verify_reshape by @TrueCP6 in #5459
• fix petsc4py breaking changes by @leo-collins in #5463
• more petsc4py fixes by @leo-collins in #5464
• Add complex Slate support by @pbrubeck in #5470
• fix assertion in vom test by @leo-collins in #5473
• Enable SingleMemoryStorageSchedule in test_checkpointing_validity by @sghelichkhani in #5455
• make the ensemble diagram not be square by @dham in #5495
• Regression tests for SingleMemoryStorageSchedule checkpoint clearing by @sghelichkhani in #5454

New Contributors

• @haldaas made their first contribution in #5349
• @manishpaulish made their first contribution in #5348
• @nwng04 made their first contribution in #5414
• @TrueCP6 made their first contribution in #5459

Full Changelog: 2026.4.3...2026.10.0