[vtkusers] Allowing repeated vertices in a tree

[Tim Gallagher]

Hi,

I have a structured grid that I made into a vtkMutableDirectedGraph and at various points I convert it into a tree using the vtkBoostBreadthFirstSearchTree. I use the output of that filter to do a search with either the vtkTreeDFSIterator or vtkTreeBFSIterator. Everything is going well until one branch of the tree search ends early. 

For example, assume that I have 4 nodes that make up a square. These nodes are indexed by their (i,j) locations -- so (0,0) is the lower left corner, (1,0) is the lower right corner, (0,1) the upper left corner and (1,1) the upper right corner. When I build my directed graph, I set the edges:

(0,0)->(1,0)
(0,0)->(0,1)

(1,0)->(1,1)
(0,1)->(1,1)

Now I want to use my search tree to find the paths from (0,0) to (1,1). The search will correctly report one path:

(0,0)->(0,1)->(1,1)

but the second path ends one vertex early:

(0,0)->(1,0)

which I assume is because the tree does not allow a vertex to have multiple connections. 

Is there a way to allow the (1,1) node to be included in both branches so I can get the complete path? Right now, when IsLeaf() == True and I am not on a node where the path is supposed to end, I manually follow the only remaining out edge in my original graph to find the proper end point. But it would be nice/clearer if the tree search wouldn't report a leaf node early. 

Thanks,

Tim