Thanks all for your ideas... I have one further query.. Scenario...
Vertex_id-->LongWritable Vertex_value-->MyVertexValueWritable( it consists of composite value--> double,double ) Edge_value->FloatWritable Input given to giraph is in following format... [0,0,[[1,1],[3,3]]][1,0,[[0,1],[2,2],[3,1]]][2,0,[[1,2],[4,4]]][3,0,[[0,3],[1,1],[4,4]]][4,0,[[3,4],[2,4]]] What vertex input format should i give to execute the program??? Any Ideas?? Thanks On Sun, Nov 17, 2013 at 5:12 PM, <ikapo...@csd.auth.gr> wrote: > You can also set a variable outside of the compute function, at the > private part of the class. You will have to instantiate it at superstep 0 > though, else you will have a NullPointerException thrown, in case you use > it at superstep 1. > > > > > Quoting Jyoti Yadav <rao.jyoti26ya...@gmail.com>: > > Thanks Ameya...I will give a try to your ideas... >> >> >> On Sun, Nov 17, 2013 at 3:17 PM, Ameya Vilankar <ameya.vilan...@gmail.com >> >wrote: >> >> In your scenario, you want to store some value that is obtained in >>> Superstep 1, so that it is available to a vertex in all the subsequent >>> supersteps. The best place to do that is to store it on the vertex >>> itself. >>> The simplest example is ShortesPath Example where you store the current >>> lowest distance on the vertex, and when you receive a message you update >>> it >>> with the new lowest mistake. I assume that in your program you don't want >>> to update the value after Superstep 1. So don't. Just keep an extra >>> variable in your vertex value class and set it in superstep 1 so that it >>> can be used by the vertex in all the following steps. >>> >>> But if you want to store global information i.e in superstep 1, every >>> vertex computes and stores a value and in the subsequent supersteps, a >>> vertex needs access to the stored values of all the vertices, you need to >>> make those values global. The only way to do it is to use a persistent >>> aggregator. In superstep 1, every vertex computes the value and then >>> sends >>> it to the persistent aggregator that can contain a hashmap from the >>> vertex >>> id to the value. This value will persist across all the supersteps since >>> the aggregator is a persistent one. Will be available to every vertex >>> too. >>> >>> >>> On Sun, Nov 17, 2013 at 1:11 AM, Mirko Kämpf <mirko.kae...@cloudera.com> >>> wrote: >>> >>> Hi, >>>> >>>> if it is a local value, just important for that given vertex, it might >>>> work with a local variable, maybe even a more complex data structure, >>>> e.g. >>>> a Stack or a FIFO buffer, to handle "old" data. I do not consider to >>>> exchange data between vertexes, only within one vertex over time. >>>> >>>> I write this here, to share my idea, but I am not really sure if a >>>> Giraph >>>> vertex works like this. It's just how I would try it ... >>>> >>>> But I think we will see a definitive answer soon. >>>> >>>> Have a nice day! >>>> Mirko >>>> >>>> >>>> On Sun, Nov 17, 2013 at 6:55 AM, Jyoti Yadav < >>>> rao.jyoti26ya...@gmail.com>wrote: >>>> >>>> Hi folks... >>>>> >>>>> while executing my program ,i came across a doubt which is creating >>>>> problem... >>>>> >>>>> Scenario.... >>>>> >>>>> In compute() function, >>>>> Suppose in superstep1 each vertex want to save some value so that every >>>>> vertex can use its previously saved value in upcoming supersteps...Is >>>>> it >>>>> possible??? >>>>> >>>>> >>>>> Any ideas are really appreciated... >>>>> >>>>> Thanks... >>>>> Jyoti >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> > > >
