About · Software

Software

Most of my research ends up as code. I release it publicly, mostly under open licenses and with documentation, so that others can check and reuse it.

Codes

Codes being developed or maintained are labeled active; the others stay on GitHub as published with their papers. To get started, see the table below.

CodeResearch area

Cosmological Simulations

Which of my codes serve which research area. Made with AI assistance (Claude).

Effortless in active development (Python, MIT license). An algorithm for linear image reconstruction that, like IMCOM, controls the point spread functions of output images, but is 50 to 60 times faster in simulations of Roman's survey and has a smaller memory footprint. Its programming interface is general enough for uses beyond weak lensing and beyond Roman. I designed and wrote it. Papers: Cao 2026a, Cao 2026b; background in Cao and Roman HLIS Cosmology PIT 2026.
MapHub running daily (Python). Scores each day's new arXiv preprints in astrophysics and AI for their relevance to each participant, from a short research portfolio that each participant writes, and shows the scores as a heatmap: selecting yourself shows the papers that matter most to you, and selecting a paper shows who is most likely to answer questions about it. A language model assigns the scores against a published rubric. MapHub, which I lead with teammates Kyle Heyblom, Eva Albalghiti and Dimitrios Simatos, is a carpentry of the Schmidt AI in Science Fellowship; I designed and built its scorer and web viewer with AI assistance (Claude Code). Anyone can run a MapHub of their own for other arXiv listings, following the instructions.
PyIMCOM maintained by the team (Python, MIT license). Image combination for the Roman Space Telescope, developed by the Roman HLIS Cosmology Project Infrastructure Team, with tests, continuous integration and documentation. I led the refactoring of IMCOM into this object-oriented package, which reduced the computing cost by about an order of magnitude, and I added a configuration interface and docstrings to make it easier to use (Cao et al. 2025). It produced the IMCOM coadds of OpenUniverse2024, a shared simulated sky for Roman and Rubin, and I support its users with documentation, onboarding and a hack session (2025).
YREC maintained by the YREC team (Fortran). The Yale Rotating Evolution Code. I have helped maintain and modernize it, as one of its contributors and a coauthor of its public data release (Pinsonneault et al. 2026). Its web laboratory, YRECLab, runs YREC in the browser (try it).
mesa_apokasc (Python, MIT license). The MESA models and analysis behind my comparison of stellar models with APOKASC-3 red giants (Cao and Pinsonneault 2026), with the MESA inlists (input files) and visualization notebooks on Zenodo.
ContEvol (Mathematica notebooks, MIT license). The examples for the ContEvol numerical methods (Cao 2025).

Where to start

Code	Start here
Effortless	the README and examples in the repository; the method is explained in Cao 2026a
MapHub	the live heatmap, then the code
PyIMCOM	the documentation, which includes installation and configuration
YREC	the repository and its public data release (Pinsonneault et al. 2026)
mesa_apokasc	the visualization notebooks on Zenodo
ContEvol	the Mathematica notebooks in the repository, read alongside Cao 2025

How to cite

If my software helps your work, please cite the papers that describe it:

Effortless: Cao 2026, arXiv:2607.06674, and Cao 2026, arXiv:2607.09862.
PyIMCOM: Cao et al. 2025, ApJS 277, 55 (doi:10.3847/1538-4365/adb580), and the original IMCOM paper, Rowe, Hirata and Rhodes 2011, ApJ 741, 46 (arXiv:1105.2852).
ContEvol: Cao 2025, Mathematics 13, 3981 (doi:10.3390/math13243981).
mesa_apokasc: Cao and Pinsonneault 2026, ApJ 997, 120 (doi:10.3847/1538-4357/ae22d1), and the data on Zenodo.
YREC: Pinsonneault et al. 2026, ApJ 1006, 220 (doi:10.3847/1538-4357/ae71cf).

BibTeX entries are available from each paper's page on NASA ADS ("Export citation").