DIMACS10 set: clustering/G_n_pin_pout                               
source: http://www.cc.gatech.edu/dimacs10/archive/clustering.shtml  
                                                                    
This graph has been generated using a two-level Gnp random-graph    
generator.  First, each vertex chooses a cluster to belong to,      
iid randomly. Then, in the spirit of the Erdos-Renyi model,         
cluster-internal edges are created with a given internal            
probability each, then cluster-external edges are created with a    
smaller external probability each. The parameters for this          
instance are: 100000 vertices, 316 clusters, the internal and       
the external edge probability are chosen such that the expected     
number of cluster-internal and the expected number of cluster-      
external incidences of a node are both five. Such a graph is simple.
For references, details and a dynamic version see the project page: 
http://i11www.iti.uni-karlsruhe.de/en/projects/spp1307/dyngen