On Fri, 16 Jul 2010, Adam Spargo wrote:
I don't see why you can't just pass get(vertex_component, g) as the component map in connected_components()
Yes, that works, code attached. I've also changed to using pointers for my graph and filtered graph so that I can use new and delete.
Why do you need to use pointers? Anyway, you might want to consider scoped_ptr or shared_ptr for those to ensure that the graphs are cleaned up appropriately when you are done with them.
In my real code I have a StringGraph class with Graph and FilteredGraph member pointers. I'm assuming that I should free any memory associated with FilteredGraph, before I allocate a new one, as I could have many many components.
I doubt it will have much memory associated with it. The filtered_graph class has only three members: a reference to the underlying graph, the vertex predicate, and the edge predicate. If you make your vertex predicate refer to an external property map (note that property maps are small and cheap to copy too) and use keep_all as the edge predicate, the filtered_graph object itself will be tiny and fast to allocate/deallocate.
Also I will want to deallocate the memory for the whole Graph before the program finishes as I need to use it for something else. So is delete the best way? Does the destructor for Graph/FilteredGraph actually release all the memory? I don't see any other clean-up functions in the documentation.
Yes, the destructors clean everything up. Be sure to destroy the filtered_graph before destroying its underlying graph, but constructing them in the necessary order and using local variables or scoped_ptr will do that automatically.
Look at boost::keep_all (in filtered_graph.hpp); that can be used to keep all of a certain kind of entity.
It's seems to me that these filters are only actually called when you ask for vertices or edges of the FilteredGraph. That being true I guess I would need both function objects?
You don't need the edge predicate if you're using an induced subgraph (which I believe you are). Filtering the endpoints of an edge to ensure that both vertices are present in the filtered graph is done automatically no matter what edge predicate you use, so keep_all will work for what you want to do. -- Jeremiah Willcock