# Wednesday, August 26, 2009

I’ve just made a release of QuickGraph 3.3 on CodePlex. Along with the usual bug fixes, this version brings a set of new graph data structures based on delegates. Instead of taking care of the storage, these graphs simply ‘query’ delegates for vertices and out-edges. You can use them to bridge any existing graph data structure in your code with QuickGraph – with almost no performance/memory penalty. (Delegate graphs can also be used to deal with graphs that won’t hold in memory but that’s another story).

Let’s see this with an example. Suppose, we have a simple graph representation using a jagged array, int[][] graph, where each edge is defined as (i, graph[i][j]) :

image

In order to use this graph with QuickGraph, we ‘wrap’ it up into a delegate graph. There are a number of extension methods in GraphExtensions that take care of the common cases. Delegate graphs rely on 2 delegates: one that returns the vertices, the other one out-edges:

image

At this point, we can apply any of the algorithms that QuickGraph provides. For example, computing a topological sort of the vertices:

image 

The new delegate graphs are ready to be downloaded at http://quickgraph.codeplex.com/Release/ProjectReleases.aspx .

Happy programming!

posted on Wednesday, August 26, 2009 8:34:18 AM (Pacific Daylight Time, UTC-07:00)  #    Comments [0]