Directed Graphs

Question

Hello,

I am having some issues with computing the centrality measures using directed/ or non-directed computations.

My network looks like this A <--> B <--> C --> D --> E --> F -->C. I have tried to represent this using edges with arrows on them. My issue is how to represent the edges connecting A to B and B to C. If I use an edge with no arrows I get different results. If I use two edges with arrows so they end up pointing one in each direction, I get different results.

I thought that an edge with no arrow is unidirectional? How come then, if I go to 'tools' --> 'reverse selected edges' on the edges with no arrows, it changes the results of my analysis?

Thanks!

Answer 1

yEd works with directed graphs and there are no undirected edges in directed graphs.

The arrows are a purely visual decoration. (Indeed nothing keeps you from creating an edge that has a source arrow but no target arrow).

As a consequence, if there is a connection from A to B and from B to A, you will have to use two edges (one from A to B and one from B to A). Moreover, two edges from A to B, one with a source arrow and one with a target arrow will not work. (I strongly recommend using only target arrows for all of your edges, otherwise it is very hard to determine if the edge direction is "correct".)