Posted by
Attila Bernáth on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Spargel-pagerank-with-sinks-tp92p94.html
Dear Stephan,
Thank you for your answer.
> With "sinks" in the graph, you mean vertices with no out-links?
Yes, I do.
> There might be a simple trick, by adding to each vertex an edge-to-self (put
> an entry in the diagonal of the adjacency matrix).
>
> I have not thought through the implications 100%.
> @ssc Can you elaborate on this?
I don't think that this works.
>
>
> What would always work is that you gather statistics about how much
> probability is accumulated in the sinks and redistribute it across the other
> nodes.
>
> The iteration aggregators allow you to do this. They can sum up the
> probability in the message sender function (when there is no outgoing edge),
> and re-add it to the non-sink nodes (by accessing the aggregate from the
> previous iteration).
Thank you for the idea. I was trying to use an aggregator, but I
thought that the aggregate from the previous iteration is of no use.
I will try this.
Thanks.
Attila
>
> Have a look at the function "registerAggregator()" on the
> "VertexCentricIteration", and the Functions "getIterationAggregator()" and
> "getPreviousIterationAggregate()" on the VertexUpdateFunction and the
> MessagingFunction.
>
>
> Stephan
>
> On Thu, Sep 18, 2014 at 5:01 PM, Attila Bernáth <
[hidden email]>
> wrote:
>>
>> Dear All,
>>
>> I wonder how to write the pagerank program in the spargel API if there
>> might be sinks in the graph.
>>
>> What is the nicest way to solve this?
>>
>> Thank you for your answer.
>>
>> Attila
>
>