Best numerical libraries to use in iOS development


I’m just starting in iOS development and my goal is to develop an engineering app that uses many matlab-like functions and algorithms. (numerical analysis, root finding, special functions, matrix operations, etc).

So, what is the best scientific library out there that can help me create this app and plays nicely along with swift and ios? would prefer free libraries with no legal problems for commercial distribution if finally it is published to the app store.