It looks to me like Amethyst uses nalgebra for it’s math. Browsing nalgebra’s docs, it looks great!.. for math. There are a lot of utility functions that seem to be totally missing from nalgebra that are useful for computer graphics — for example rotating a vector2 given just an angle. Instead, I have to construct a new rotation matrix and then apply this. Not great for making a game when you need to rotate things all the time.
I think nalgebra-glm would be better suited for amethyst. It still uses nalgebra but provides an api like glm which is fantastic for game dev.