R Programming By Example

Using an old-school approach with Fortran

We will start with an old-school approach using Fortran first. If you are not familiar with it, Fortran is the oldest programming language still under use today. It was designed to perform lots of calculations very efficiently and with very few resources. There are a lot of numerical libraries developed with it, and many high-performance systems nowadays still use it, either directly or indirectly.

Here's our implementation, named sma_fortran(). The syntax may throw you off if you're not used to working with Fortran code, but it's simple enough to understand. First, note that to define a function technically known as a subroutine in Fortran, we use the subroutine keyword before the name of the function. ...