Simple network measures

Instructions


You need a Java Runtime Environment installed to run the applet above.

Click on one of the four network buttons to change between different network topologies. Change the layout with the Kamada-Kawai algorithm by pressing the button with the same name. The nodes are relaxed until you press stop. When the button ''Move node'' is active you can also move the nodes by clicking and dragging with the mouse. This button toggles between the three mouse functions: ''Move node'', ''Add/remove link'', and ''Select pair''. Activate ''Add/remove link'' and click and drag the mouse between two nodes to add a link (or remove a link if there is already a link between the pair). Activate ''Select a pair'' and click and drag the mouse between two nodes to show the shortest path between the pair (the button ''Shortest path'' must be activated).

The buttons ''Triangles'' and ''Squares'' report the number of closed loops of length three and four around each node together with the total number of triangles and squares in the network.

Trace a shortest path between two nodes when ''Shortest path'' is selected, by pushing the mouse button on one of the nodes and releasing the button on the other node (make sure that ''Select pair'' is active). The applet also reports the average shortest path for every node as well as the network average.

Press ''Betweenness'' and investigate the flow over the network with the betweenness measure. The size of each node and link is plotted proportional to the fraction of shortest paths they participate in. The value is also reported as a number next to the node.

Push ''No constraints'' and randomize the network by selecting new random pairs of nodes for each link in the network. Push ''Fix degree'' and swap random pairs of links so that the degree sequence of the network is kept fixed.

Philosophy


Is the number of triangles high or low? The shortest paths short or long? The only way to find out is to compare with a proper null model — a randomized counterpart of the network.

This interactive applet makes it easy to make this comparison and to capture the effect different network topologies have on basic network measures, as well as the effect of addition and removal of individual links.