FastPPV

Run it as follows:

1. Select Hub nodes:

   1. basic methods as in VLDB2013 paper: SelectHubs.java
   2. community-based hub selection (extended VLDBJ paper): SelectCommunityHubs.java

2. Offline precomputation: Offline.java Parameters:

   1. type of hubs (e.g. random, utility-1)
   2. number of precomputed hubs
   3. forceUpdate? (1 for true; 0 for false)

3. Online processing: Online.java Parameters:

   1. type of hubs (e.g. random, utility-1)
   2. number of precomputed hubs
   3. number of expansions (\eta)

4. Exact PPV computation: OnlineExact.java //Using the iterative method to compute exact PPV scores.

Note that, all the other parameters are specified in a config file (see Config.java).