PSI

PSI (the Phase Space Intersector) is a Python module for post-processing the outputs of cosmological simulations. PSI applies the Phase Space Sheet discretization (see Abel et al. 2012) to a set of particles, then volume-samples the density and velocity fields (as well as higher-order moments) onto a Cartesian grid. Anyone can use PSI to produce smooth and continuous density and velocity maps from particle data! The volume-sampling procedure is geometrically exact, and converves mass down to machine precision.

The low-level volume-sampling routines are based on the r3d software, described in Powell & Abel (2015) and LA-UR-15-26964.

---

Usage:

• First, git clone the repository and cd into it

• Then, python setup.py install.

• To use in Python, simply import PSI as psi or similar

• See tutorial/Tutorial.ipynb for a guide to using PSI!

---

License and attribution:

PyPSI is free to use under the MIT License. See source files for the full license text.

If you use PyPSI for your research, please cite:

• Devon Powell and Tom Abel. An exact general remeshing scheme applied to physically conservative voxelization. Journal of Computational Physics, 297:340–356, 2015a (link)

• Devon M. Powell. r3d: Software for fast, robust geometric operations in 3D and 2D. Los Alamos National Lab technical report, LA‑UR‑15‑26964, 2015a (link)

---

Developers:

Devon M. Powell (Stanford, MPA Garching)

Tom Abel (Stanford, SLAC)

Goran Jelic-Cizmek (University of Geneva)