Re: question about Pagerank example

[Avery Ching]

PageRankBenchmark doesn't have an use an output format.  If you'd like 
to see the output, just add a VertexOutputFormat (that matches the 
types).  You could start with JsonBase64VertexOutputFormat.


i.e. in PageRankBenchmark.java add

job.setVertexOutputFormatClass( JsonBase64VertexOutputFormat.class);


On 7/27/12 5:10 PM, Amir R Abdolrashidi wrote:

Hi everyone,

I am not sure whether this is right question or not but does anyone 
know if we can see the output of PageRankBenchmark example that is 
provided on the tuotial?


Thanks

-Amir

Re: Heterogeneous Vertex Types

[Avery Ching]

  
  
Hi Nick,
  
  Giraph needs to have be able to instantiate the vertex id, value,
  edges, and messages and there can only be a single type for each
  of them.
  
  That being said, since all the types are user chosen, you can
  basically implement types that support multiple types inside of
  it.  As a simple, stupid example
  
  class MessageA {
  ...
  }
  
  class MessageB {
  ...
  }
  
  class MultiMessage implements Writable {
      private MessageA msgA;
      private MessageB msgB;
  
      private boolean useMsgA;
  
      pubic MessageA getMsgA(){
          return msgA;
      }
  
      pubic MessageB getMsgB(){
          return msgB;
      }
  
      ...
  }
  
  I didn't try and compile it, but hopefully you get the idea.  =)
  
  On 7/27/12 9:52 AM, Jonathan Bishop wrote:

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 
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 

  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,