Hi Apostolos, What exactly is not working probably when overriding messages and vertex values? I haven't used Giraph in a while but these seem like minor configuration issues.
About the algorithm: You're right it's possible to do bc in Giraph but as Claudio said and unless I misunderstood your approach, what you propose doesn't seem to scale to large graphs, say with 1B vertices. Running 1B SSSPs in a row wouldn't be feasible. But yes, it's doable and correct but it wouldn't be scalable. semih On Wed, Feb 12, 2014 at 7:54 AM, Claudio Martella < [email protected]> wrote: > i don't think the point is whether following your approach, which is a > concatenation of SSSP, this is possible, but whether given the the sizes of > graphs your approach is actually feasible. > > About your questions, you have to implement a type for your Vertex Value > and one for the Message, and make sure they implement Writable correctly, > to ensure serializability. > > P.S.= you should post (and subscribe) to [email protected], AFAIK > user-help@ does not exist. > > > On Wed, Feb 12, 2014 at 3:34 PM, Apostolos Koutras < > [email protected]> wrote: > >> >> >> >> >> >> Hi fellow developer Semih Salihoglu, >> >> In the past day, I am struggling on completing calculating Betweeness for >> a graph. >> Browsing in some forums, some stated that this cannot be done. >> >> This point of view is simply put WRONG!. >> >> I have uploaded my work in https://github.com/koutras/gb >> where everyone with an interest can browse and provide insight, as I have >> been developing >> for about 12 straight hours and I have not the right experience yet. >> >> The main algorithm is based on SimpleShortestPathsComputation for the >> main algorithm (brande's algorithm) but I needed to store extra values in >> each node, and as an effect override >> the message also. >> >> The trick I've thought about for the algorithm to work is provide the >> input of nodes in ascending >> value, starting from 1 to number of nodes, and as such, to complete a bfs >> each time I have to >> wait for number of nodes supersteps each time. This can easily be done by >> mod(superstep,nodes_num). >> >> After the end of that phase I do some calculations in each node, and I >> clear the distance value, >> in order to continue running the SimpleShortestPaths algorithm but with >> the next vertex >> as a source in ascending order. >> >> I was also based >> on BrachaTouegDeadlockComputation for overriding message and vertex value, >> >> >> (message is based on BrachaTouegDeadlockMessage and vertex value on >> BrachaTouegDeadlockVertexValue located in utils >> on respect.) >> >> The things I had found difficulty so far is not the algorithm by itself >> that is the brande's algorithm, >> but integrating the following things. >> >> 1) overriding the value of vertex with mine using myVertex.java >> Overriding the Serialization functions for my implementation >> according to >> BrachaTouegDeadlockVertexValue. >> >> >> >> 2) overriding the message that a node is passing to another with >> myMessage.java >> I've added the accessors that I wanted but I dont now what to do >> with readFields, and write, >> that the BrachaTouegDeadlockMessage has, for my implementation >> >> >> Any help on the above matters is very appreciated. Thank you all, and >> sorry for the long post >> So this CAN be done! If this algorithm is effective is another topic of >> conversation. >> Thanks for your time, and once again sorry for the long post >> >> > > > -- > Claudio Martella > >
