Let say I have 5 nodes which are sending message to 6th node.
each 5 node sending one message to 6th node containing some value.
I want to intercept all those 5 messages going towards 6th node.
after that I want to find the maximum value contained among those 5 nodes.
and send single message from combiner to 6th node which contain only the
maximum value among those messages.
I have tried to write a simple code for it but it seems not working. I dont
know what I am doing wrong.
In the code below, node 0 trying to send 3 message to node 1.
My final goal is, in superstep=1, node 1 should receive only one message
with contain 4 only.
My current code receiving all the 3 messages and hence I am getting final
value of variable:"test" as 7.
public class CombinerTest extends BasicComputation<LongWritable,
DoubleWritable, FloatWritable,DoubleWritable>
{
@Override
public void compute(Vertex<LongWritable, DoubleWritable, FloatWritable>
arg0,Iterable<DoubleWritable> arg1) throws IOException {
if(getSuperstep()==0 && (arg0.getId().get()==0))
{
sendMessage(new LongWritable(1),new DoubleWritable(1));
sendMessage(new LongWritable(1),new DoubleWritable(2));
sendMessage(new LongWritable(1),new DoubleWritable(4));
}
DoubleWritable test=new DoubleWritable(0);
if(getSuperstep()==1)
{
for(DoubleWritable messages :arg1)
{
test.set(test.get()+messages.get());
// changed=true;
}
arg0.setValue(test);
}
arg0.voteToHalt();
}
public void combine(LongWritable vertexIndex, DoubleWritable
originalMessage, DoubleWritable messageToCombine)
{
if(originalMessage.get() > messageToCombine.get())
{
originalMessage.set(messageToCombine.get());
}
}
public DoubleWritable createInitialMessage()
{
return new DoubleWritable(Double.MAX_VALUE);
}
}
please help me to figure out correct way to write code.
Thanks Maria.
Nishant Gandhi
M.Tech. CSE
IIT Patna
On Mon, May 12, 2014 at 11:11 AM, Maria Stylianou <[email protected]> wrote:
> Hi Nishant,
>
> Can you be more specific? Are you trying to combine all incoming messages
> of a vertex into one message? What do you mean combine? Add values? Or
> append to a list?
> The message can be a list so you can put all values together.
>
> Maria
>
>
> On Sunday, May 11, 2014, nishant gandhi <[email protected]> wrote:
>
>> Hi,
>> I am trying to write code that use Combiner. I want to combine all
>> message into one for each vertex. That one message contains message value
>> bigger than all the other message values.
>> Please help.
>>
>> Nishant Gandhi
>> M.Tech. CSE
>> IIT Patna
>>
>
>
> --
> Sent from Android Mobile
>
