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From lee fei <chirs...@gmail.com>
Subject Re: Can Aggregator store a queue or a map for global communication?
Date Sat, 01 Dec 2012 09:23:57 GMT
Yes, I find the MapWritable in org.apache.hadoop.io, it's very useful.
Thank you very much!

On Sat, Dec 1, 2012 at 4:38 PM, Thomas Jungblut
<thomas.jungblut@gmail.com>wrote:

> Like I told you, the aggregator works through the message type of your
> vertex. This must be Writable, so if you find a HashMap that is Writable
> (maybe you have to write your own) and this is your message type in your
> algorithm. Then this will work automatically if you implement your
> reduction operations correctly in the aggregator.
>
>
>
> 2012/12/1 lee fei <chirsfei@gmail.com>
>
> > hi Thomas,
> >   I want to use an aggregator to store an HashMap, and in every
> superstep,
> > different vertexes may put or remove an element<key, value> to the
> HashMap,
> > and I am wondering at the sync phase,if the master will automatic sync
> the
> > HashMap?
> >
> > Just like this:
> >
> > superstep n:  HashMap: 1,2,3,4,5,6
> >
> >  task1 modified the aggregator:
> > HashMap(1): 3,4,5,6(task1 remove 1,2)
> >
> >  task2 modified the aggregator:
> > HashMap(2):  1,2,3,4,5,6,7,8(task2  add 7,8)
> >    ....
> > and after the sync phase also in next superstep:
> > the HashMap become: 3,4,5,6,7,8
> >
> > Did I got it? the namenode will automatic do this?
> >
> >
> > On Thu, Nov 29, 2012 at 8:52 PM, lee fei <chirsfei@gmail.com> wrote:
> >
> > > Thanks for you quick reply:)
> > >
> > > Best wishes for you:D
> > >
> > >
> > > On Thu, Nov 29, 2012 at 8:01 PM, Thomas Jungblut <
> > > thomas.jungblut@gmail.com> wrote:
> > >
> > >> Yes, if they are Writable and are part of your vertex message or value
> > >> type.
> > >> You may want to have a look at MapWritable or other serializable
> > >> collections in the org.apache.hadoop.io package.
> > >>
> > >> 2012/11/29 lee fei <chirsfei@gmail.com>
> > >>
> > >> > Hi,
> > >> >
> > >> >   I am a newbie to hama,Can Aggregator in graph package store an
> > >> Arraylist
> > >> > or a HashMap for some special usages?
> > >> >
> > >> > Thank you for you attention~
> > >> >
> > >>
> > >
> > >
> >
>

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