Jacobi method: From a naïve implementation to a modern Fortran multithreaded one

In a previous post , I used the Jacobi method to illustrate some merits of Fortran over Python for teaching purposes. Since then, I received a handful of messages asking how to write efficient Fortran code. Because of its algorithmic simplicity, the Jacobi method makes for an excellent case study. In this post, we’ll see how to go from a naïve implementation taking a minute to solve a linear…