Nick, I am guessing it is because Giraph needs to move vertices around and needs to construct them before it reads in their serialization. I am new to Giraph myself so this may be incorrect. Maybe Avery could comment.
Jon On Fri, Jul 27, 2012 at 6:32 AM, Nick West <nick.w...@benchmarksolutions.com > wrote: > Thanks for the quick reply. > > That (using one uber-class) was my initial thought when I ran into this > problem, however I was wondering if there was a solution that would use the > type hierarchy (which admittedly is a bit more flexible in scala than java, > so this may not be possible). Is there something in the Giraph > architecture that precludes this? > > Thanks, > Nick > > On Jul 25, 2012, at 7:11 PM, Jonathan Bishop wrote: > > Nick, > > You may want to reconsider your approach as I don't think Giraph will be > happy with this. > > How about using a new vertex value class with BasicVertex which can do > both behaviours for you? Same for edge and message classes. This should be > enough do what you want. > > Jon > > On Wed, Jul 25, 2012 at 3:29 PM, Nick West < > nick.w...@benchmarksolutions.com> wrote: > >> Hi, >> >> I'm working on implementing a belief propagation algorithm over Giraph. >> (Do you know if anyone has done this before?) This requires having (at >> least) two different types of vertices implemented (values and factors) and >> different types of messages sent between different vertices. >> >> I've been able to set up and run my own vertices (with my own custom >> readers and writers), however, whenever I try to extend this to a more >> complex case I run into problems. For example, suppose aI have the >> following two vertex types: >> >> class FooVertex() extends BasicVertex[IntWritable, IntWritable, Text, >> IntWritable] >> class BarVertex() extends BasicVertex[IntWritable, IntWritable, Text, >> IntWritable] >> >> (both of which run fine in the basic set up), and I then configure the >> GiraphJob with the following, >> >> job.setVertexClass(classOf[BasicVertex[IntWritable, IntWritable, Text, >> IntWritable]]) >> >> (as opposed to with FooVertex or BarVertex). >> >> I get a null pointer error in GraphMapper (at line 204 in the version >> of the code that I am using - just after the log statement about the input >> format vertex index type not being known, and at the line where it checks >> if the vertextIndexTypes are the same). >> >> Do you know what is causing this? (The stack trace is below.) Have you >> tried to instantiate different classes for different vertices in the past? >> >> One last piece of info that might explain things: I'm developing in >> scala, which I have seen behave a little bit poorly with java reflection - >> could that be a cause? >> >> Thanks, >> *Nick West >> ** >> * >> Stack Trace: >> >> ./bin/hadoop jar >> ~/code/watchdog/modules/inference/target/inference-assembly-1.0.jar >> bmrk.inference.giraph.IdiotRunner ising ising_out 4 >> Input arguments: >> [0] = ising >> [1] = ising_out >> [2] = 4 >> setting vertex class to: org.apache.giraph.graph.BasicVertex >> setting vertex input class to: >> bmrk.inference.giraph.IdiotVertexInputFormat >> setting vertex output class to: >> bmrk.inference.giraph.IdiotVertexOutputFormat >> 12/07/25 17:48:54 INFO mapred.JobClient: Running job: >> job_201207250932_0012 >> 12/07/25 17:48:55 INFO mapred.JobClient: map 0% reduce 0% >> 12/07/25 17:52:43 INFO mapred.JobClient: Task Id : >> attempt_201207250932_0012_m_000000_0, Status : FAILED >> java.lang.NullPointerException >> at >> org.apache.giraph.graph.GraphMapper.determineClassTypes(GraphMapper.java:204) >> at org.apache.giraph.graph.GraphMapper.setup(GraphMapper.java:392) >> at org.apache.giraph.graph.GraphMapper.run(GraphMapper.java:655) >> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764) >> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370) >> at org.apache.hadoop.mapred.Child$4.run(Child.java:255) >> at java.security.AccessController.doPrivileged(Native Method) >> at javax.security.auth.Subject.doAs(Subject.java:396) >> at >> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121) >> at org.apache.hadoop.mapred.Child.main(Child.java:249) >> >> >> Benchmark Solutions >> 101 Park Avenue - 7th Floor >> New York, NY 10178 >> Tel +1.212.220.4739 | Mobile +1.646.267.4324 >> *www.benchmarksolutions.com * <http://www.benchmarksolutions.com/> >> ** >> *<image001.png> >> >> >> >> * >> ** >> > > > * > Nick West > * > * > *Benchmark Solutions > 101 Park Avenue - 7th Floor > New York, NY 10178 > Tel +1.212.220.4739 | Mobile +1.646.267.4324 > *www.benchmarksolutions.com * <http://www.benchmarksolutions.com/> > ** > * > > > > * > ** >
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