To take my mind off my meetings, I spent a little time modifying the Spatial Preferred Attachment model from Aiello, Bonato, Cooper, Janssen, and Prałat’s paper A Spatial Web Graph Model with Local Influence Regions so that it changes over time.

NetworkX makes this kind of messing around pretty easy, and I find the random functions in PyMC are handy, too. Here’s what it takes to generate one of their graphs:

def make_graph(n, d, p, A1, A2, A3):
position = runiform(0, 1, size=(n, d))
affinity = runiform(0, 1, size=(n,n))
G = DiGraph()
G.add_nodes_from(range(n))
for t in range(1, n):
for s in range(t):
if distance(position[s], position[t]) \
<= (A1 * G.in_degree(s) + A2) / (t + A3):
if affinity[t, s] <= p:
G.add_edge(t, s)
return G

Here is how I animated it.

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*Related*

Does anyone know how to make this into a youtube movie?

I figured out how:

`mencoder mf://*.png -mf w=800:h=600 -ovc x264 -of avi`

Finally, I have removed the 100 meg gif animation. Final puzzle piece:

`[vimeo 17389019]`

to embed the flash video in wordpress. They should document that!