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From Eli Reisman <apache.mail...@gmail.com>
Subject Re: High-level questions about the ShortestPathsBenchmark example that ships with Giraph
Date Mon, 24 Sep 2012 22:04:55 GMT
Sorry, the Giraph website is a bit out of date regarding the
user-configurable application code. The benchmark applications are meant
for just that, and are not written to process input or output data or
results. The code you are looking for is in the examples/ dir. These are
applications (*Vertex classes) in Giraph. Regarding code from the examples/
directory: you can run it at the command line using the "giraph" script in
the bin/ dir. There are many command line options (including for IO formats
from the io/ dir) and input/output paths in your HDFS for your data. Until
better docs are up (soon, sorry!) your best bet is to read some of the
example apps in the examples/ and io/ dirs and read GiraphRunner.java and
bin/giraph script to get a feel for how user-configured command-line runs
are performed. You might also then feel comfortable writing some of your
own application code.

Sorry about the confusion, we will be posting better documentation of
application-style runs ASAP.

On Mon, Sep 24, 2012 at 1:50 PM, Magyar, Bence (US SSA) <
bence.magyar@baesystems.com> wrote:

>  Hello Giraph User Community,****
>
> ** **
>
> *( I am re-posting this question – I think I tried posting this before I
> confirmed my registration.  Please pardon if this message is a duplicate )
> *
>
> ** **
>
> This is my first post to this mailing list – I’m interested in learning
> more about Giraph and to do that I checked out the latest source code from
> https://svn.apache.org/repos/asf/giraph/trunk****
>
> and built it with maven.****
>
> ** **
>
> I am now running the shortestPathBenchMark example that ships with Giraph
> and have a few “high-level” questions:****
>
> For the sake of this discussion, I am running the example with the
> following arguments:****
>
> ** **
>
> hadoop jar giraph.jar org.apache.giraph.benchmark.ShortestPathsBenchmark
> -c 1 -e 3 -v -V 50000 -w 4****
>
> ** **
>
> The example takes about 90 seconds to complete on my 4-node hadoop cluster
> and I don’t see any errors or issues. ****
>
> ** **
>
> **1.      **In computing a Dijkstra shortest path, we are looking for the
> shortest path from one node to another.  What does ShortestPathsBenchmark use
> as the “starting” node?  The “ending” node?****
>
> **2.      **What edge weights are being used?  The arguments don’t allow
> me to specify them.****
>
> **3.      **Does ShortestPathsBenchmark produce any output data inside
> HDFS upon completion of this example, or is the example purely meant to
> visually illustrate processing time on my cluster?****
>
> **4.      **Can I feed ShortestPathsBenchmark my own graph?****
>
> **5.      **In the example above, I have specified 3 edges per vertex.
> If I were to specify only 2 edges per vertex, am I not effectively dealing
> with a graph that most closely resembles a “linked list”?  When I set –e=2,
> the processing time is still somewhat comparable to –e = 3.  Shouldn’t the
> graph be much simpler?   ****
>
> ** **
>
> I have seen the ShortestPathExample @ ****
>
> https://cwiki.apache.org/confluence/display/GIRAPH/Shortest+Paths+Example*
> ***
>
> ** **
>
> and I was planning on working through that example as well, but I thought
> I’d ask about the benchmarking example first.****
>
> ** **
>
> Thanks!****
>
> ** **
>
> ** **
>
> Bence Magyar****
>
> BAE Systems 6 New England Executive Park, Burlington MA 01803 USA****
>
> Office: +1 (781) 262-4222****
>
> Mobile: +1 (781) 879-7557****
>
> ** **
>

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