How do people usually store a Graph for VLSI routing?

I am a beginner in the field of VLSI CAD.

Now I have been working on some programming practice with Dijkstra's algorithm (find the shortest path in a graph). In such small project, I am simply using adjacency matrix to store the small toy graph.

However, a friend of mine who is also a student told me that I should not do that in a real project, because a graph of a real VLSI circuit is very larger. So an adjacency matrix is not realistic for very larger graph.

I kind of agree with him, but I like adjacency matrix because it is so easy to access, and I can find any edge I need by using "i" and "j".

Could anyone tell me how people usually store the graph of circuit in industry? What kind of data structure they are using and how to access the elements?

Thank you in advance.

adjacency list ?

Consider not-changing your graph representation right now. It sounds like it isn't a real issue, at least at the moment.

If you decide to not change your graph representation, also consider writing your code in such a way that *if* you did change it, that it would have a minor impact on the rest of your code. This means that you would use some sort of abstraction to access the graph. (like functions or class objects)

To keep it as simple as possible for now, consider using functions to access and modify the graph, instead of i&j indices into an array. If you change things later, you won't have to modify (much) the routines which are accessing the graph because the function calls would stay the same. This might also give you the opportunity to "factor out" all the stuff you keep having to do with the graph to get work done.