Getting started
The latest stable release of FEniCSx is version 0.9, which was released in October 2024. The easiest way to start using FEniCSx on MacOS and other systems is to install it using conda:
conda create -n fenicsx-env
conda activate fenicsx-env
conda install -c conda-forge fenics-dolfinx mpich pyvista
The easiest way to install FEniCSx on Debian or Ubuntu Linux is via apt:
sudo add-apt-repository ppa:fenics-packages/fenics
sudo apt update
sudo apt install fenicsx
Other installation options
The source code of all the components of FEniCSx can be found on GitHub:
Detailed instructions for installing FEniCSx from source, or using some binary distributions can be found in the installation page of the DOLFINx docs.
FEniCSx vs legacy FEniCS
FEniCSx is the latest iteration of FEniCS, and boasts a number of major improvements over the legacy library, including support for a wide range of cell types and elements, memory parallelisation, and complex number support. FEniCSx is comprised of the libraries UFL, Basix, FFCx and DOLFINx. The latest version of FEniCSx (0.9) was released in October 2024. We recommend that new users use the latest release of FEniCSx.
Updates are now very rarely made to the legacy FEniCS library. We recommend that users consider using FEniCSx instead of the legacy library. Lecacy FEniCS is comprised of the libraries UFL legacy, FIAT, FFC and DOLFIN. The latest version of legacy FEniCS (2019.1.0) was released in April 2019. Instructions for installing the legacy FEniCS (version 2019.1.0) can be found here.
Complex number support
FEniCSx introduces complex number support.
On Debian/Ubuntu Linux this is provided via the python3-dolfinx-complex package:
sudo apt install python3-dolfinx-complex
Debian/Ubuntu packages manage dolfinx builds via the version of PETSc they are built against. The Debian/Ubuntu standard installation uses the real number build. To access other builds, set the environment variable PETSC_DIR to point at the required PETSc version located under /usr/lib/petscdir. Likewise SLEPc support can be managed via SLEPC_DIR (see /usr/lib/slepcdir).
So to access complex number support in dolfinx on Debian/Ubuntu, run scripts with:
PETSC_DIR=/usr/lib/petscdir/petsc-complex python3 demo_dolfinx.py
or, with SLEPc:
PETSC_DIR=/usr/lib/petscdir/petsc-complex SLEPC_DIR=/usr/lib/slepcdir/slepc-complex python3 demo_dolfinx.py