The author gives an example of a little function written in a generic way, and shows how JIT compilation specializes it at runtime into highly optimized machine

The author gives an example of a little function written in a generic way, and shows how JIT compilation specializes it at runtime into highly optimized machine code. It’s a wonderful example of how Julia’s JIT compiler works, and how it can lead to significant speedups over even C or Fortran code in some cases.