Release 4C version 2026.3.0

[c-p-schmidt]

Steps for a new 4C release

Note

For a PATCH-release, only some of the steps below are necessary. Commits are typically added to the
main branch and cherry-picked to the release branch. That ensures that the main branch is fixed
and the PATCH itself is still compatible with all projects consuming a specific version of |FOURC|.

• Check whether all changes that should be part of the release are merged into the main-branch.
• Draft the release notes and post them as a comment to this issue (See notes below on release notes)
• Update the version number in the VERSION file in the repo. The version scheme is YYYY.MINOR.PATCH, where YYYY is the year of the release, MINOR is the number of the release in the year starting at 1, and PATCH is the patch number. PATCH is typically 0 and incremented on demand. Typically, this step only involves removing the -dev suffix from the version.
• Pick a commit from main-branch where all nightly tests have passed and the above points are satisfied. Commit: <insert the commit sha>
• Create a new branch from the commit chosen in the previous step. The branch should be named release/vYYYY.MINOR.x. Note, since all patches are maintained on this branch, the name does not contain the respective patch number.
• Create a new release on GitHub. The tag name should be vYYYY.MINOR.PATCH and the release title should be 4C version vYYYY.MINOR.PATCH. Tick 'Set as latest release' and 'Create a discussion for this release'
• Upload the 4C_metadata.yaml, 4C_schema.json and 4C_schema_completion.json to the release. You can download them as artifact from the nightly pipeline.
• Update the tags of all Docker images, e.g., 4c and 4c-dependencies-ubuntu24.04. Add the tag YYYY.MINOR.PATCH to the images, and latest if it is the latest release. You can run the script ./utilities/tag_images_for_release.sh.
• Prepare the next release in the VERSION file in the repo by incrementing the number of the release, resetting the patch number to 0, and adding the suffix -dev.

Release notes

The release notes might contain a summary of the changes since the last release or a description of the fixed bugs in a PATCH release.

We do not yet have an automated way to collect the changelog. So, this requires some manual work. You can get a draft of the release notes from GitHub (Releases -> Draft a new release -> Generate release notes).

Changelog template

What's Changed

Breaking Changes

• Renaming and some input refactoring in viscoelasthyper toolbox by @bgoderbauer in Renaming and some input refactoring in viscoelasthyper toolbox #2005
• Minor rework of MAT_electrode by @c-p-schmidt in Minor rework of MAT_electrode #2034
• Remove custom implemented functions from elchsinglemat by @c-p-schmidt in Remove custom implemented functions from elchsinglemat #2042
• Move poroelast to vtk output by @c-p-schmidt in Move poroelast to vtk output #2057
• Remove custom implemented functions: Part 2 by @c-p-schmidt in Remove custom implemented functions: Part 2 #2061
• Move heatflux and tempgrad to vtk output by @engstlerL in Move heatflux and tempgrad to vtk output #2062
• Remove custom implemented functions: Part 3 by @c-p-schmidt in Remove custom implemented functions: Part 3 #2064
• Remove thermo trait from thermo solid trait by @rjoussen in Remove thermo trait from thermo solid trait #2075
• Remove custom implemented functions: Part 4 by @c-p-schmidt in Remove custom implemented functions: Part 4 #2079
• Remove NUMMAT from MIX_Constituent_ElastHyper by @lauraengelhardt in Remove NUMMAT from MIX_Constituent_ElastHyper #2080
• Group passive/active material parameters and refactor COMBO muscle model by @lauraengelhardt in Group passive/active material parameters and refactor COMBO muscle model #2081

Major changes

• Add performance testing framework by @amgebauer in Add performance testing framework #1988
• Generate performance report by @amgebauer in Generate performance report #2020
• Collect benchmark test data and generate report by @amgebauer in Collect benchmark test data and generate report #2039
• Input: support name-based element block definition by @rjoussen in Input: support name-based element block definition #1971
• Add kokkosparallel docker and workflow by @PhilipOesterlePekrun in Add kokkosparallel docker and workflow #2162
• Enable using Kokkos with CUDA backend for MIRCO and in general by @PhilipOesterlePekrun in Enable using Kokkos with CUDA backend for MIRCO and in general #2012
• Add cmake preset to compile 4C on Darwin by @vryy in Add cmake preset to compile 4C on Darwin #1795

Dependency changes

• Patch Release of Trilinos - 16.2.1 by @jeremylt in Patch Release of Trilinos - 16.2.1 #2133

Miscellaneous

• Move scatra input from inpar to scatra by @maxiludwig in Move scatra input from inpar to scatra #1996
• Improve the error message when using DESIGN ** NEUMANN CONDITIONS: with TYPE: "orthopressure" by @lkoeglmeier in Improve the error message when using DESIGN ** NEUMANN CONDITIONS: with TYPE: "orthopressure" #1999
• Replace raw pointer usage with std::span in Map class by @dharinib98 in Replace raw pointer usage with std::span in Map class #1977
• Remove master/slave in beaminteraction by @davidrudlstorfer in Remove master/slave in beaminteraction #1998
• Move xfem input from inpar to xfem by @maxiludwig in Move xfem input from inpar to xfem #1997
• Move s2i input from inpar to scatra by @maxiludwig in Move s2i input from inpar to scatra #2001
• Add performance test for monolithic solid scatra interaction by @c-p-schmidt in Add performance test for monolithic solid scatra interaction #2004
• Fix reuse of NOX::Nln::Adapter by resetting state by @maxiludwig in Fix reuse of NOX::Nln::Adapter by resetting state #2003
• Node numbering in node set printout when external mesh files are read by @ischeider in Node numbering in node set printout when external mesh files are read #1980
• Slightly increase test tolerance of failing embedded mesh test by @bgoderbauer in Slightly increase test tolerance of failing embedded mesh test #2011
• Fix distance threshold bug ScalarInterp by @dragos-ana in Fix distance threshold bug ScalarInterp #2010
• [TSI] Fix solver increment handling in partitioned solver by @rjoussen in [TSI] Fix solver increment handling in partitioned solver #2022
• Introduce central manager for viscoelastic states by @bgoderbauer in Introduce central manager for viscoelastic states #2018
• Add temperature derivative evaluation to refJC material by @rjoussen in Add temperature derivative evaluation to refJC material #2016
• Update tolerance in beam test by @rjoussen in Update tolerance in beam test #2026
• [beaminteraction] Assemble penalty contribution into FE matrix by @maxfirmbach in [beaminteraction] Assemble penalty contribution into FE matrix #2028
• Prepare viscoplastic factor for thermo-coupling by @rjoussen in Prepare viscoplastic factor for thermo-coupling #2015
• Fix 2D solid output of out-of-plane components by @bennoschoenstein in Fix 2D solid output of out-of-plane components #2027
• Minor rework of ssi solvers by @c-p-schmidt in Minor rework of ssi solvers #2031
• Add more verbose error message to particle code by @ppraegla in Add more verbose error message to particle code #2030
• Add performance result badges to the README by @c-p-schmidt in Add performance result badges to the README #2033
• Add Windkessel terminal unit in 1D pipe flow by @engstlerL in Add Windkessel terminal unit in 1D pipe flow #2023
• Clean parallel issues by @georghammerl in Clean parallel issues #2029
• Add possibility to use functions for bodyforces in porofluid_pressure_based* problems by @lkoeglmeier in Add possibility to use functions for bodyforces in porofluid_pressure_based* problems #2035
• Introduce non-local growth remodeling by @tuchpaul in Introduce non-local growth remodeling #2019
• Minor rework of global_full by @c-p-schmidt in Minor rework of global_full #2038
• [MultSplit Material] Add thermal stress evaluation helper by @rjoussen in [MultSplit Material] Add thermal stress evaluation helper #2037
• Add benchmark result badge to the README by @c-p-schmidt in Add benchmark result badge to the README #2043
• Add element timing by @LaSi5002 in Add element timing #2025
• Enable monitor dbc in monolithic solvers by @rjoussen in Enable monitor dbc in monolithic solvers #2044
• Enable possibility to use functions for body force contributions in porofluid_pressure_based_elast* framework by @lkoeglmeier in Enable possibility to use functions for body force contributions in porofluid_pressure_based_elast* framework #2040
• Enable inelastic growth in impl-fiber by @tuchpaul in Enable inelastic growth in impl-fiber #2052
• Add a completion-oriented schema wrapper by @rjoussen in Add a completion-oriented schema wrapper #2006
• chore: remove old plasticity inpar by @davidrudlstorfer in chore: remove old plasticity inpar #2056
• Further infrastructure improvements for viscoelastic materials by @bgoderbauer in Further infrastructure improvements for viscoelastic materials #2053
• [Particle] Fix probe for the message with the size tag by @vovannikov in [Particle] Fix probe for the message with the size tag #2058
• Introduce output verbosity levels in reduced lung by @maxiludwig in Introduce output verbosity levels in reduced lung #2060
• [Particle] Reduce complexity of Particle::PDNeighborPairs::communicate_bond_list() by @vovannikov in [Particle] Reduce complexity of Particle::PDNeighborPairs::communicate_bond_list() #2063
• Rename master/slave to source/target in adapter by @lauraengelhardt in Rename master/slave to source/target in adapter #2055
• Allow vtu mesh import for all beam types in 4C by @isteinbrecher in Allow vtu mesh import for all beam types in 4C #2071
• Adapt the workflow schedules by @c-p-schmidt in Adapt the workflow schedules #2072
• Rename master slave in core by @lauraengelhardt in Rename master slave in core #2066
• Add thermal effects to the viscoplastic factor by @rjoussen in Add thermal effects to the viscoplastic factor #2041
• Refactor central infrastructure for viscoelastic materials by @bgoderbauer in Refactor central infrastructure for viscoelastic materials #2073
• Monolithic non-local stimulus by @tuchpaul in Monolithic non-local stimulus #2067
• Try fix randomly failing sti test by @c-p-schmidt in Try fix randomly failing sti test #2077
• Implement quasilinear generalized Maxwell model for structural dynamics by @bgoderbauer in Implement quasilinear generalized Maxwell model for structural dynamics #2076
• Futher renaming of master/slave to source/target by @lauraengelhardt in Futher renaming of master/slave to source/target #2078
• Fix build error on lnm cluster thought by @c-p-schmidt in Fix build error on lnm cluster thought #2085
• feat: beaminteraction -> potential: add potential reduction functions by @davidrudlstorfer in feat: beaminteraction -> potential: add potential reduction functions #2088
• Update the lnm cluster presets to actual current capabilities at the cluster bruteforce by @c-p-schmidt in Update the lnm cluster presets to actual current capabilities at the cluster bruteforce #2087
• Fix sign in 4 ele Maxwell residual by @maxiludwig in Fix sign in 4 ele Maxwell residual #2089
• Clean-up solid materials by @lauraengelhardt in Clean-up solid materials #2090
• Flush error output before MPI abort in main by @rjoussen in Flush error output before MPI abort in main #2092
• Preset: Update IMCS cluster preset with vtk by @reginabuehler in Preset: Update IMCS cluster preset with vtk #2096
• Further cleanup in preparation for the Adaptive Estimate Interpolation algorithm by @dragos-ana in Further cleanup in preparation for the Adaptive Estimate Interpolation algorithm #2082
• Add thermal effects to the multiplicative split material by @rjoussen in Add thermal effects to the multiplicative split material #2083
• Correct invalid names in journal files by @c-p-schmidt in Correct invalid names in journal files #2086
• Fix circular references in anisotropy framework by @lauraengelhardt in Fix circular references in anisotropy framework #2094
• Add 3D solid superposition material by @lauraengelhardt in Add 3D solid superposition material #2095
• Cleanup of scatra ele boundary calc methods by @c-p-schmidt in Cleanup of scatra ele boundary calc methods #2099
• Move inpar_structure to structure_new_input by @maxiludwig in Move inpar_structure to structure_new_input #2103
• Validate output argument contains a prefix by @maxiludwig in Validate output argument contains a prefix #2106
• Rename master/slave to target/source in poro, structure, and TSI modules by @lauraengelhardt in Rename master/slave to target/source in poro, structure, and TSI modules #2101
• Change solver from Superlu to MUMPS for failing beam test by @c-p-schmidt in Change solver from Superlu to MUMPS for failing beam test #2107
• Tensor migration by @tuchpaul in Tensor migration  #2084
• Enable vtk based output in red-airways by @lkoeglmeier in Enable vtk based output in red-airways #2100
• Fix monitor_dbc DOF iteration in 2D by @bennoschoenstein in Fix monitor_dbc DOF iteration in 2D #2036
• [Particle] Cache senders and receivers of the refreshed particles by @vovannikov in [Particle] Cache senders and receivers of the refreshed particles #2074
• feat: beaminteraction -> potential: add potential reduction distributed endpoint moment compensation by @davidrudlstorfer in feat: beaminteraction -> potential: add potential reduction distributed endpoint moment compensation #2091
• [beaminteraction]Dual Hermite shapefunctions for Lagrange Multipliers by @dharinib98 in [beaminteraction]Dual Hermite shapefunctions for Lagrange Multipliers #2009
• Fix get_comm usage in reduced_lung by @rjoussen in Fix get_comm usage in reduced_lung #2119
• Fix gmsh node reordering for corner cases by @rjoussen in Fix gmsh node reordering for corner cases #2118
• Adaptive endpoint quadrature by @davidrudlstorfer in Adaptive endpoint quadrature #2120
• Remove post_output() by @rjoussen in Remove post_output() #2125
• Silence Clang-23 Unused Warnings by @jeremylt in Silence Clang-23 Unused Warnings #2127
• Refactor the drucker prager model to use tensors instead of matrices by @ischeider in Refactor the drucker prager model to use tensors instead of matrices #2007
• [Particle] Do not use ParticleObjShrdPtr for commicating particle data by @vovannikov in [Particle] Do not use ParticleObjShrdPtr for commicating particle data #2117
• [beaminteraction] Allow output of energy in beam-to-solid volume mortar simulations by @isteinbrecher in [beaminteraction] Allow output of energy in beam-to-solid volume mortar simulations #2135
• [Particle] Make sdata const and return rdata in particle utils by @vovannikov in [Particle] Make sdata const and return rdata in particle utils #2141
• [beaminteraction]Correct dual hermite shapefunctions by @dharinib98 in [beaminteraction]Correct dual hermite shapefunctions #2128
• [geometric search] Allow beam bounding volume based on beams surface by @isteinbrecher in [geometric search] Allow beam bounding volume based on beams surface #2140
• [beaminteraction] Update beam-solid preconditioner config by @maxfirmbach in [beaminteraction] Update beam-solid preconditioner config #2143
• [beaminteraction] Post filter penalty contribution by @maxfirmbach in [beaminteraction] Post filter penalty contribution #2144
• A hybrid Ogden-type material model with compression-tension asymmetry control by @lauraengelhardt in A hybrid Ogden-type material model with compression-tension asymmetry control #2109
• Remove unused code by @rjoussen in Remove unused code #2151
• Update contributing guidelines w.r.t. AI-assisted contributions by @lauraengelhardt in Update contributing guidelines w.r.t. AI-assisted contributions #2156
• Move fluid input by @davidrudlstorfer in Move fluid input #2150
• Find libbacktrace by name, not hardcoded suffix by @georghammerl in Find libbacktrace by name, not hardcoded suffix #2160
• Update PR template with disclosure of AI assistance by @lauraengelhardt in Update PR template with disclosure of AI assistance #2158
• Preparations for fluid output to vtk based by @c-p-schmidt in Preparations for fluid output to vtk based #2163
• Migrate fluid-hdg output to vtk-based output by @c-p-schmidt in Migrate fluid-hdg output to vtk-based output #2164
• Migrate fluid-poro output to vtk-based output by @c-p-schmidt in Migrate fluid-poro output to vtk-based output #2165
• Fix cut kernel comparison by @vryy in Fix cut kernel comparison #2161
• Move fluid external forces and fluid hdg output by @c-p-schmidt in Move fluid external forces and fluid hdg output #2167
• Add dynamic rebalance to structure problems by @LaSi5002 in Add dynamic rebalance to structure problems #2108
• Adapt fluid conditions output by @c-p-schmidt in Adapt fluid conditions output #2170
• [bugfix] Fix two flaws regarding strain energy output in the hyperelastic framework by @ischeider in [bugfix] Fix two flaws regarding strain energy output in the hyperelastic framework #2147
• Reduced lung vtu input by @maxiludwig in Reduced lung vtu input #2166
• Add a performance test for reduced-lung by @maxiludwig in Add a performance test for reduced-lung #2142
• Particle Writable State Access by @jeremylt in Particle Writable State Access #2171
• Insert Global::Problem at porofluidelast/-scatra algorithm boundary by @bgoderbauer in Insert Global::Problem at porofluidelast/-scatra algorithm boundary #2169
• Detect inconsistent fiber entry and throw an error by @ischeider in Detect inconsistent fiber entry and throw an error #2168
• Particle: Clean up THROW vs ASSERT by @jeremylt in Particle: Clean up THROW vs ASSERT #2178
• Particle Use Enum Class by @jeremylt in Particle Use Enum Class #2176
• Migrate output of FluidImplicitTimeInt to vtk-based output by @c-p-schmidt in Migrate output of FluidImplicitTimeInt to vtk-based output #2172
• Support inhomogenous element blocks (in input only) by @rjoussen in Support inhomogenous element blocks (in input only) #2123
• Fix cell_block id access in reduced lung by @rjoussen in Fix cell_block id access in reduced lung #2181
• Docker update more robust dependencies hash by @ppraegla in Docker update more robust dependencies hash #2175
• Add structured tree terminal unit by @engstlerL in Add structured tree terminal unit #2180
• Remove redundant definition from input file by @c-p-schmidt in Remove redundant definition from input file #2185
• [Actions] Temporarily disable kokkoscuda_build workflow due to ccache issue by @PhilipOesterlePekrun in [Actions] Temporarily disable kokkoscuda_build workflow due to ccache issue #2186

Contributors

List of all contributors who authored, committed, reviewed, or commented on accepted pull requests for this release.

• Authors / Committers:
  @amgebauer @maxiludwig @bgoderbauer @c-p-schmidt @engstlerL @rjoussen @lauraengelhardt @lkoeglmeier @dharinib98 @davidrudlstorfer @LaSi5002 @jeremylt @dragos-ana @ppraegla @georghammerl @tuchpaul @vovannikov @isteinbrecher @reginabuehler @bennoschoenstein @ischeider @maxfirmbach @PhilipOesterlePekrun @vryy

• Reviewers:
  @davidrudlstorfer @c-p-schmidt @bgoderbauer @ischeider @lkoeglmeier @dragos-ana @rjoussen @maxfirmbach @lauraengelhardt @tuchpaul @mayrmt @isteinbrecher @amgebauer @jeremylt @ppraegla @slfuchs @georghammerl @maxiludwig @engstlerL @vovannikov @mairehenke @knarfnitram @bennoschoenstein @m-frey @dharinib98 @sebproell @PhilipOesterlePekrun

New Contributors

• @LaSi5002 made their first contribution in Add element timing #2025

Thanks to first-time contributors to 4C!

Full Changelog: v2026.2.0...v2026.3.0

[c-p-schmidt]

@4C-multiphysics/developers: I just compiled the changelog for the upcoming release. Feel free to adapt it if necessary.