Examples

Notebooks

For the documentation, we provide several Jupyter notebooks that illustrate how to use PSYDAC to solve different types of problems. They can be found in the notebooks directory, but are also generated as part of the documentation and can be accessed here:

Notebooks:

• Solving Poisson’s equation on a square domain with a mapped grid
• Solving Poisson’s equation on non-periodic topological domains
• Solving Helmholtz’s equation on non-periodic topological domains
• Finite element projections of scalar and vector-valued functions
• 3D example with VTK and ParaView
• Example of computing approximative eigenvalues with PETSc
• Example of solving the curl-curl eigenvalue problem
• Solving the time-harmonic Maxwells equations on a multipatch domain
• Computing the vector potential of a solenoidal field on a Torus

FEEC Examples

In the FEEC examples directory, you will find several examples of how to use PSYDAC to solve problems arising within the Finite Element Exterior Calculus (FEEC) framework. These examples include:

• Poisson problems

• General curl-curl eigenvalue problems

• Time-harmonic Maxwell equations with source terms

• Time-dependent Maxwell equations

Performance

There are also some examples in the performance directory explaining the assembly algorithms used in PSYDAC.

Running examples in parallel

We very strongly recommend that every parallel script runs its main function through psydac.utilities.parallel_utils.parallel_run_from_cli, as done by the examples in psydac/feec/polar/examples.

Without it, an uncaught exception terminates only the process which raised it, while the other processes hang as soon as they wait for a message from it (e.g. in a collective operation). On a cluster, such a job keeps its allocation until it reaches the wall-time limit. With parallel_run_from_cli, the traceback is printed and all the processes are terminated by calling MPI_Abort, whichever MPI launcher is used (e.g. mpirun, mpiexec, or srun in a batch job).

Note that MPI_Abort terminates the other processes without any cleanup (finally blocks, context managers, atexit handlers), hence an HDF5 file which is being written may be left incomplete.