Re: [igraph] Running Igraph in parallel

[Gabor Csardi]

Lorenzo,

some points. The implementations in the igraph C library are not
parallel, so for igraph it does matter whether it runs on a 4-processor
machine or on a 1-processor machine, it will run with the same speed.

What you can do, however, is to run multiple igraph instances (or
R instances if you use R) on the same machine, and can make the 
analysis faster. In R see the 'snow' package on how to do this easily,
this would be the cheapest option, in terms of the amount of work 
required.

Another option is to install a batch scheduler system on your 
cluster, like 'Condor' 'Sun Grid Engine', 'LFS', etc. THe scheduler 
can then "optimally" distribute the work among the machines. 
Again, this won't make a single betweenness calculation faster, 
but if you do it for 10 graphs then you can run them in parallel.

Best,
Gabor


On Wed, May 28, 2008 at 11:16:45AM +0200, Lorenzo Isella wrote:
> Dear All,
> My institute seems finally to have some budget to spend on hardware equipment.
> This means I could run more intensive simulations, in whose analysis
> the igraph library plays an important part.
> Now, as a consequence, I may end up with the analysis of non-directed
> graphs with e.g. 10^5  nodes.
> Is this doable with the igraph library? And above all: since I am
> likely to generate many of these graphs, can (and how) I use igraph in
> parallel to take full advantage of a cluster?
> Cheers
> 
> Lorenzo
> 
> 
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-- 
Csardi Gabor <address@hidden>    UNIL DGM