davids7788/ptarmigan

Nonlinear Compton scattering at moderate intensity

ptarmigan

Ponderomotive trajectories and radiation emission

Build

All of ptarmigan's default dependencies are Rust crates, which are downloaded automatically by Cargo. Building the code in this case is as simple as running:

cargo build --release [-j NUM_THREADS]

where NUM_THREADS is the number of separate threads that Cargo is allowed to spawn.

There are three optional features: with-mpi, which enables parallel processing via MPI; fits-output, which switches the output format for distribution functions from text to FITS; and hdf5-output, which switches the output format for particle arrays to HDF5. Each requires some external libraries to be installed. with-mpi needs an MPI library (ptarmigan is tested against OpenMPI, versions <= 3.1, and MPICH) and the Clang compiler. fits-output and hdf5-output require CFITSIO and libhdf5 respectively. To build with one or all of these, run:

cargo build --release --features with-mpi,fits-output,hdf5-output [-j NUM_THREADS]

The ptarmigan changelog can be found here.

Specify problem

ptarmigan takes as its single argument the path to a YAML file describing the input configuration. Output is automatically written to the same directory as this file. The inputs for some test problems can be found in examples. Starting from scratch, the input needs to contain the following sections:

• control
• laser
• beam

and optionally

• constants

The structure of the input file is described in detail here.

Run

Assuming ptarmigan has been downloaded to ptarmigan and already built,

cd ptarmigan
[mpirun -n np] ./target/release/ptarmigan path/to/input.yaml

will run the code, parallelized over np MPI tasks (if MPI support has been enabled).