This package contains some simple tools for writing fluid-dynamics solvers using pseudo-spectral methods. The basic structure of the package is closely patterned on the spectral DNS code of Mortensen and Langtangen, which can be found here and is described here. That package requires a substantial software stack, and is built on a generic spectral Galerkin package, which makes it more difficult to tinker with. This package is designed to be as transparent and easy to modify as possible, for use as a research code.
PsDNS depends on several other Python packages, most importantly mpi4py for parallelization. It also uses numpy and `scipy <https://scipy.org`_ for numerics, matplotlib for plotting, and sphinx for documentation. The easist way to install these dependencies is using conda. If you have conda installed, you can just create a new environment using:
conda create -n <environment name> mpi4py scipy matplotlib sphinx
Note that this has been tested and works well on OS X. For
high-performance computer systems, good MPI performance relies on
efficient use of the custom interconnects that are specific to your
system. Therefor it is important to compile the mpi4py package to
use your system-specifica tuned MPI libraries, not the off-the-shelf
versions provided by conda. Please consult the documentation for the
specific HPC system you are using to figure out how to do that.
Example scripts can be found in the examples directory. The
source code for these example are straightforward and can be used as a
template to for other problems. To run one of these examples without
installing PsDNS:
PYTHONPATH=. python examples/tgv.py
PsDNS has a Sphinx manual, including
detailed documentation of the API. In order to build the manual,
Sphinx needs access to the internet (to link to dependency packages)
and to be able to load the psdns source code (to access Python
docstrings).
To build the documentation from a fresh checkout of the code, first make sure your Python environment is set to one that includes all the dependencies for PsDNS (i.e., one from which you can successully run the examples) and then type:
cd doc PYTHONPATH=../psdns make html
for HTML documentation, or for PDF:
PYTHONPATH=../psdns make latexpdf
PsDNS comes with an extensive test suite. The full test suite can be run using:
PYTHONPATH=. python -m unittest -v
This code was approved for open source release (C21086) under the BSD-3 license (see :file:`LICENSE.txt`)
©2021. Triad National Security, LLC. All rights reserved.
This program was produced under U.S. Government contract 89233218CNA000001 for Los Alamos National Laboratory (LANL), which is operated by Triad National Security, LLC for the U.S. Department of Energy/National Nuclear Security Administration. All rights in the program are reserved by Triad National Security, LLC, and the U.S. Department of Energy/National Nuclear Security Administration. The Government is granted for itself and others acting on its behalf a nonexclusive, paid-up, irrevocable worldwide license in this material to reproduce, prepare derivative works, distribute copies to the public, perform publicly and display publicly, and to permit others to do so.