HELIOS-K is an opacity calculator for exoplanetary atmospheres. It takes a line list as an input and computes the line shapes of an arbitrary number of spectral lines (~millions to billions). HELIOS-K is capable of computing 100,000 spectral lines in 1 second; it is written in CUDA, is optimized for graphics processing units (GPUs), and can be used with the HELIOS radiative transfer code (ascl:1807.009).
https://ui.adsabs.harvard.edu/abs/2021ApJS..253...30G or https://ui.adsabs.harvard.edu/abs/2015ApJ...808..182G