A Computer Algebra System (CAS) is a software package designed to manipulate mathematical expressions and equations, perform symbolic and numerical calculations, and visualize results.
Siril is an image processing software for astronomical CCD imaging, designed for calibration, stacking, alignment, and post-processing of deep-sky images.
HEC-RAS is a river analysis system that allows users to perform one-dimensional steady and unsteady flow calculations for a wide variety of hydraulic engineering applications.