On 08/09/2011 10:48 AM, Steffen Schaper wrote:
The graph_draw() function defaults to 'neato' if the graph is smaller than 1000 nodes, and uses 'sfdp' otherwise. And indeed, it seems like 'sfdp' ignores the pin property. This is a graphviz limitation.
Maybe you could add another check to draw/__init__.py at line 312:
layout = "neato" if g.num_vertices() <= 1000 else "fdp" if pos is not None and pin else "sfdp"
Yes, something like this would be a good idea.
Thanks, setting maxiter=1 made things faster (subjectively, I haven't done timings). What I meant originally was that the difference between sfdp without pin and neato/fdp (I tried both now) with pin isn't as big as I thought. My naive expectation was that it takes most of the time to do the layout, so if we tell graphviz where to put the nodes, the rest should be a lot quicker.
Although the difference between sfdp and fdp/neato is very noticeable for larger graphs, I would expect that both fdp/neato with pin=True would be _much_ faster than sfdp, since the layout algorithm is not run. In my experience, this is always what I found. I would be interested in understanding why you perceive this not to be the case... How long does it actually take to plot with sfdp and neato with pinning?