Re: Efficiently storing a directed graph

Kelly Jones wrote:
> I have a directed graph (nodes and edges) that I want to store
> "efficiently": given two nodes, I want to quickly find the shortest
> path between them. The graph is NOT acyclic (it's not a tree), is
> fairly "sparse" (about 10000 edges for 2500 nodes), and changes
> occasionally.
>
> I know PostgreSQL/MySQL can store graphs (as one table of nodes and
> one table of edges that reference the nodes), but I think finding the
> shortest path between two nodes is quite inefficient that way.
>
> I know PostgreSQL/MySQL have special "plugins" (like PostGIS for
> PostgreSQL) for specific problems. Is there a directed graph plugin?

Perhaps use PL/R plus one of the R packages available here:
http://cran.stat.ucla.edu/web/packages/
(e.g. http://cran.stat.ucla.edu/web/packages/igraph/index.html)
to enable data storage in Postgres and data processing in R.

R:
http://www.r-project.org/

PL/R:
http://www.joeconway.com/plr/

HTH,

Joe