[SciPy-user] Scipy for Cluster Detection

[Lorenzo Isella]

Dear All,
I hope this will not sound too off-topic.
Without going into details, I am simulating the behavior of a set of 
particles interacting with a short-ranged, strongly binding potential. I 
start with a number N of particles which undergo collisions with each 
other and, in doing so, they stick giving rise to clusters.
The code which does that is not written in Python, but it returns the 
positions of these particles in space.
As time goes on, more and more particles coagulate around one of these 
clusters. Eventually, they will all end up in the same cluster.
Two particles are considered to be bounded if their distance falls below 
a certain threshold d.
A cluster is nothing else than a group of particles all directly or 
indirectly bound together.
Having said so, I now need an efficient algorithm to look for clusters, 
since at the very least I need to be able to count them to study how the 
number of clusters evolve in time.
Is there anything suitable for this already implemented in SciPy? I 
wonder if people in Astronomy have similar problems if they need e.g. to 
detect/study clusters of stars.
Simply I would like not to re-invent the wheel and it goes without 
saying that any suggestions here are really appreciated.
Many thanks and a nice Xmas break to everybody on this list.

Lorenzo