I'm sorry for typing error. > However, many problems (e.g., finding isomorphic subgraphs, computing clustering coefficient, and finding cohesive groups) that have global states don't have such global sync problems.
However, many problems (e.g., finding isomorphic subgraphs, computing clustering coefficient, and finding cohesive groups) that don't have global states don't incur such global sync problems. Above is right statement. -- Hyunsik Choi Database & Information Systems Group, Korea Univ. http://diveintodata.org On Wed, Feb 3, 2010 at 8:08 PM, Hyunsik Choi <[email protected]> wrote: > Hi Felix Halim, > > Such terrible global sync problem may only occurs in a few of problems > that have global states. We are trying to research better ways. > However, many problems (e.g., finding isomorphic subgraphs, computing > clustering coefficient, and finding cohesive groups) that have global > states don't have such global sync problems. The graph package of Hama > is appropriate to these problems. > > We will think about PathOthersHaveFollowed(). Thank you for your > advice! If you are interested in this project, why don't you > participate in our project? > > Best regards, > -- > Hyunsik Choi > Database & Information Systems Group, Korea Univ. > http://diveintodata.org > > > On Wed, Feb 3, 2010 at 5:54 PM, Felix Halim <[email protected]> wrote: > > > > On Wed, Feb 3, 2010 at 4:41 PM, Edward J. Yoon <[email protected]> > wrote: > > >>> I think the needToVisit() function might as well need to communicate > > >>> with other machine: > > > > > > Hmm, You're exactly right. In that example, needToVisit() function > > > checks the IsVisited from some shared-space (e.g., HBase or DBMS, ..., > > > etc). We wrote with intent to simplify it. > > > > From the pseudocode, I see that every Vertex will request IsVisited. > > In a large graph, the HBase or DBMS will be overwhelmed by many tiny > > requests from each Vertex. > > Does the needToVisit() has "bulk query" that aggregates the tiny > > requests into a single request? > > > > > > > Integer is the distance at "Map<Vertex, Integer> input, Map<Vertex, > > > Integer> nextQueue", but it could be replaced as other object. for > > > example, new PathWeHaveFollowed(). Then, perhaps we need not some > > > shared-space. > > > > But we also need to know PathOthersHaveFollowed() don't we? > > That's why we need HBase to store the global "visited" states of each > node. > > > > Felix Halim >
