The directed acyclic graph test

Let's take a look at what a directed acyclic graph (DAG) is first. A directed acyclic graph is a graph that is directed, which means that the edges from a given vertex A to B will be directed in a particular direction (A->B or B->A) and is acyclic. Acyclic graphs are those graphs that are not cyclic, which also means that there is no cycle (they don't go around in cycle).

What is a good example of a DAG? A tree or even a trie. We all know what they are because it was discussed in one of the previous chapters of this book. A good example of using trie is to store the words of dictionaries and have a spell check algorithm. We will not go further into details about this, but in the context of visualization and to check whether a graph is acyclic or not, we will determine the Python packages that offer methods to test whether a graph is acyclic or not.

NetworkX has a convenient function called is_directed_acyclic_graph (Graph). Here is an example...