Introduction

Main packages in the SNA4DS course

Overview of igraph and network graph objects

There are two main packages for basic graph generation and manipulation: the igraph package and the statnet package. Actually, statnet is a suite of packages that work together. In this course, we will will make use of several packages from the statnet suite.

The igraph package creates a graph object of type igraph. The statnet suite creates a graph object of type network. There are many things you can do in both packages. Both packages can generate graphs and do basic manipulation, so here you should just use the package whose API you like best. The igraph package provides more mathematical functions to apply to the graph data and the statnet suite provides loads of statistical models that the igraph package does not do.

The snafun package

The igraph package and statnet suite are jointly very powerful and can support much of your analyses of network data. However, as you read above, they each require graph objects that have specific structures and they can’t deal with a graph object that has a different structure. So, if you want to use the functions from both the igraph and the sna packages, you need network data in igraph format (for the igraph package), in network format (for the network package and some of the sna package) and in matrix format (for many of the functions in the sna package). In other words, you will have to convert your data between these formats and you also have to deal with the differing API’s between these various packages.

Believe it or not, this is a pain and quite annoying.

THE snafun PACKAGE TO THE RESCUE!

The snafun package does three things:

• First, it provides an (fairly) consistent API, so you don’t have to constantly figure out what a specific argument means for each function;
• Second, most of the functions in the snafun package work on both objects of class igraph or network. As a result, you can do what you want to do, without bothering with whether the object you work on is of class igraph or network.
• Third, by removing the pain coming from the constant switching between the two groups of packages and their inconsistent API, you can now actually focus on the fun of network analysis, rather than the frustration.

Oh, and there is a fourth advantage too: the authors of the snafun package are cool people. So, if you have the need for a new function in the package, just get in touch with us and we’ll see what we can do for you.

:-)