Built on Flax (ascl:2504.026), DeepSSM emulates gravitational wave (GW) spectra produced by sound waves during cosmological first-order phase transitions in the radiation-dominated era. It uses neural networks trained on an enhanced version of the Sound Shell Model (SSM). The code provides instantaneous predictions of GW spectra given the phase transition parameters, while achieving agreement with the enhanced SSM model. DeepSSM is particularly suitable for direct Bayesian inference on phase transition parameters without relying on empirical templates, such as broken power-law models.

fastSHT performs spherical harmonic transforms on a large number of spherical maps. It converts massive SHT operations to a BLAS level 3 problem and uses the highly optimized matrix multiplication toolkit to accelerate the computation. GPU acceleration is supported and can be very effective. The core code is written in Fortran, but a Python wrapper is provided and recommended.

CosmoGRaPH explores cosmological problems in a fully general relativistic setting. Written in C++, it implements various novel methods for numerically solving the Einstein field equations, including an N-body solver, full AMR capabilities via SAMRAI, and raytracing.