DrL is a force-directed graph layout toolbox focused on real-world large-scale graphs (see References). This toolbox includes:
DrL has been used on graphs up to 2 million vertices. It is written in C++ and can be used with Linux, Windows, and Mac.
DrL is one of the few force-directed layout algorithms that can scale to over 1 million nodes, making it ideal for large graphs. However, small graphs (hundreds or less) do not always end up looking so good. This algorithm expects similarity networks, so some networks may need to derive another network with weighted edges declaring the similarity between nodes.
The version of DrL included in NWB only does the standard force-directed layout (no recursive or parallel version).
Force-directed layout of large networks.
DrL expects the edges to be weighted, directed edges where the weight (greater than zero) denotes how similar the two nodes are (higher is more similar). The NWB version has several parameters. The edge cutting parameter expresses how much automatic edge cutting should be done. 0 means as little as possible, 1 as much as possible. Around .8 is a good value to use. The weight attribute parameter lets you choose which edge attribute in the network corresponds to the similarity weight. The X and Y parameters let you choose the attribute names to be used in the returned network which corresponds to the X and Y coordinates computed by the layout algorithm for the nodes.
To see the VxOrd/DrL layout in GUESS, you must run the following command in the GUESS interpreter (click the 'Interpreter' tab near the bottom of the GUESS interface):
for n in g.nodes: n.x = n.xpos * 100 n.y = n.ypos * 100
(Whitespace is significant.)
This assumes you used the default 'xpos' and 'ypos' labels suggested by the DrL algorithm.
This code is translated into English as the following: For every node in the network,
make the GUESS x coordinate equal to the DrL-generated X coordinate times 100 make the GUESS y coordinate equal to the DrL-generated Y coordinate times 100
We multiply by 100 because DrL coordinates are on a smaller scale than GUESS coordinates, so we need to enlarge the DrL coordinates to see the network structure (otherwise it will appear that the nodes are nearly on top of each other).
DrL was created at Sandia National Labs