### Fancy way to calculate polymer chain model characteristics via NumPy

NumPy is the fundamental package for scientific computing with Python. It contains among other things: a powerful N-dimensional array object sophisticated (broadcasting) functions tools for integrating C/C++ and Fortran code useful linear algebra, Fourier transform, and random number capabilities Besides its obvious scientific uses, NumPy can also be used as an efficient multi-dimensional container of generic data. Arbitrary data-types can be defined. This allows NumPy to seamlessly and speedily integrate with a wide variety of databases. The ndarray is also the basic data structure of JIT tools like Numba, which boosts python dramatically. Recently, I wrote a program about calculation of the gyration tensor, center of mass and end to end vectors of polymer chain models under periodic boundary condition, and I found that using NumPy and Numba would finish the task in very few lines of codes, and also applicable to various situations. Here is the code: def pbc(r, d): return