Re: All pairs shortest paths?

2014-03-26 Thread Ryan Compton
To clarify: I don't need the actual paths, just the distances.

On Wed, Mar 26, 2014 at 3:04 PM, Ryan Compton compton.r...@gmail.com wrote:
 No idea how feasible this is. Has anyone done it?


Re: All pairs shortest paths?

2014-03-26 Thread Matei Zaharia
Yeah, if you’re just worried about statistics, maybe you can do sampling (do 
single-pair paths from 100 random nodes and you get an idea of what percentage 
of nodes have what distribution of neighbors in a given distance).

Matei

On Mar 26, 2014, at 5:55 PM, Ryan Compton compton.r...@gmail.com wrote:

 Much thanks, I suspected this would be difficult. I was hoping to
 generate some 4 degrees of separation-like statistics. Looks like
 I'll just have to work with a subset of my graph.
 
 On Wed, Mar 26, 2014 at 5:20 PM, Matei Zaharia matei.zaha...@gmail.com 
 wrote:
 All-pairs distances is tricky for a large graph because you need O(V^2) 
 storage. Do you want to just quickly query the distance between two 
 vertices? In that case you can do single-source shortest paths, which I 
 believe exists in GraphX, or at least is very quick to implement on top of 
 its Pregel API. If your graph is small enough that storing all-pairs is 
 feasible, you can probably run this as an iterative algorithm: 
 http://en.wikipedia.org/wiki/Floyd–Warshall_algorithm, though I haven’t 
 tried it. It may be tough to do with GraphX.
 
 Matei
 
 On Mar 26, 2014, at 3:51 PM, Ryan Compton compton.r...@gmail.com wrote:
 
 To clarify: I don't need the actual paths, just the distances.
 
 On Wed, Mar 26, 2014 at 3:04 PM, Ryan Compton compton.r...@gmail.com 
 wrote:
 No idea how feasible this is. Has anyone done it?