Development (current)

whitepaper “Why FeenoX is different”
small fix when writing to VTU/VTK from .msh version 2.2
updated Tutorial #0
variable nearest_node_threshold can be modified to change the multi-dim interpolation behavior near nodes
functions vecmean, vecvariance and vecsd

v1.2 (Sep 2025)

VTK/VTU writer now supports sparse or unsorted node tags
basic example for a large-deformation mechanical case (NAFEMS GNL-5 benchmar problem)
outputs from WRITE_RESULTS or WRITE_MESH in vtu or vtk for transient problems create a .pvd file
instruction PROBLEM_SOLVE is not mandatory anymore, now FeenoX can guess where it should be called
keyword READ_DATA to read variables and vectors from files
PROBLEM can define MESH in a single line without an explicit READ_MESH instruction
neo-hookean material model
MMS verification for mechanical with both sdef & ldef
Saint Venant-Kirchoff material model for ldef
biasc large-deformation formulation for mechanical

misc fixes for Debian packaging
steady-state writer in VTU .vtu format
skip some tests in big-endian architectures
READ_MESH can read CalculiX's .frd output files
utils/fee2ccx converter from FeenoX's .fee to CalculiX's .fee
links to examples and tests in HTML manual
cleanups to create debian directory in Salsa (see https://salsa.debian.org/jtheler/feenox)
distribution binaries are dynamic instead of static
BC type adiabatic in thermal
fixed TIME_PATH with PETSc and SUNDIALS
improved vector initialization syntax
remove compilation date to allow reproducible builds
BCs as arrays instead of linked lists
option --ast
BC GROUPS to select many labels at once
cleanups to create Debian dsc
use config.h instead of version.h
compute perimeters using second-order precision
bump GSL to v2.8
INTEGRATE expressions of nx, ny and nz
create _cog variables for points as well
fix for evaluation of derivatives at arbitrary locations
paper in FOSS: https://doi.org/10.21105/joss.05846

option --check
README for engineers, hackers and academics
thermal tutorial
thermal radiation tests
two-dimensional quasi-random number sequences
non-zero Neumann BCs in neutron diffusion
LABEL in now an alias for PHYSICAL_GROUP in MATERIAL
explicit fission spectrum
EIGEN_DIRICHLET_ZERO keyword
special variable mumps_ictnl_14 to control MUMPS' over-relaxation factor
improved MPI execution
verification with MMS
PRINTF and PRINTF_ALL instructions
improved memory handling when building elemental objects
PREALLOCATE and ALLOW_NEW_NONZEROS options
choose either to fail or allow missed BCs
updated internal naming of FEM matrices to match the doc
dump element drawings, node ordering and shape functions with --elements_info
cleaned up source distributions
CI using Github actions
Los Alamos criticallity benchmarks in tests
support for reading VTK v5 files
WRITE_RESULTS keyword
split examples by problem type
YAML blocks in input file for metadata are allowed (so far they are ignored by FeenoX)
$0 (or ${0} or $(1)) expands to the base name of the main input, i.e. without the .fee extension
bracketed arguments so ${1}1$(1) is a valid string
multi-group neutron transport with discrete ordinates ($S_N$ method)
mimicked-nodes BCs
read mesh fields from VTK files

unofficial Debian/Ubuntu packages
added jacobian for temperature-dependent conductivity
updated LE10 benchmark
read time-dependent functions in .msh files
detect/handle hanging nodes
muti-dof BCs using expressions for mechanical 0=expression of space & displacements
volumetric forces in mechanical
stress linearization according to ASME VIII Div\ 2 Sec\ 5.
tangential and radial symmetry as multi-dof BCs using the penalty method
solve (small) systems of non-linear equations given as expressions
functions over meshes using vectors
argument --pdes lists the available PDEs FeenoX can solve
auto-detect PDE directories: if one adds or deletes one directory from src/pdes FeenoX will compile anyway.
faster direct inversion of 3x3 matrices using code from PETSc
separated initial conditions from initial guess

initial development version to move stuff from wasora/Fino/milonga to the new FeenoX repository.