Hi Avery, 

can you elaborate bit?

So I load vertices in order, but with skipping:

so partition 0 will read vertex 0, vertex 3, 6, …
partition 1 will read vertex 1, vertex,4, …

Do you mean the vertices must be consequtive in the 
split?

Aapo



On Oct 1, 2011, at 6:57 PM, Avery Ching wrote:

> Unfortunately, someone (probably me), needs to make a wiki on this issue.  
> Currently, we require that your vertices are globally sorted by vertex id and 
> that the vertices read in each input split are in order by vertex id.  That 
> probably explains the weirdness you are seeing.  This issue is being 
> addressed (albeit slowly because of new job) in 
> https://issues.apache.org/jira/browse/GIRAPH-11.  The issue is also described 
> a bit more fully there.
> 
> Avery
> 
> On 10/1/11 12:44 PM, Aapo Kyrola wrote:
>> 
>> 
>> Hi,
>> 
>> I have a very difficult problem to debug. Several vertices seem to be 
>> duplicated -
>> maybe I am not reading the inputs properly? Here is more info:
>> 
>> - I have three input splits and use three workers. I have written my own 
>> input-dataformat
>> (part of the zip I sent few days ago). In split one, i have ids mod 3 = 0, 
>> then ids mod 3 = 1 etc.
>> 
>> I added some extra debug vertex id 875600:
>> 
>> - I checked that the vertex 875600 is read only once, with 8 edges by adding 
>> a System.out.println debug:
>>  ::: READ: 875600 ; 8 : [81066, 271870, 272882, 483962, 621946, 723717, 
>> 834555, 845506]
>> 
>> - in the vertex.compute I will write the hostname of the computer and how 
>> many messsages, and
>> eedges there are. From here I see that this vertex appear on two different 
>> hosts because I get 
>> two types of outputs:
>> 
>> hostA.ml.cmu.edu 875600* => 0.0 / 0.0 msgs=0/6813839/8
>> 
>> hostB.ml.cmu.edu 875600* => -3.4657359027997265 / -3.4657359027997265 
>> msgs=5/6813839/0
>> 
>> 
>> Note that the last string the debug is 
>> num-of-messages/num-edges/num-out-edges.
>> 
>> In the hostB, this vertex has no edges, but on host A, it has the correct 8 
>> edges.
>> 
>> --
>> 
>> Does it matter how I split the vertex-ids?
>> 
>> 
>> 
>> ps. For next report I will make an Apache account. Too busy now..
>> 
>> 
>> Aapo Kyrola
>> Ph.D. student, http://www.cs.cmu.edu/~akyrola
>> 
> 

Aapo Kyrola
Ph.D. student, http://www.cs.cmu.edu/~akyrola

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