Thanks Sean & Ted. That is what I've observed experimentally. I was
going to pursue a ClusterWriteable along the lines of VectorWritable but
will try PolymorphicWritable<Cluster> first. Looking at it, I see it
does send the class name which might be onerous as Sean observed except
for the fact that I am only sending (k) clusters between each mapper and
the reducer. I will report on this an an hour or so.
On 2/12/12 9:01 AM, Ted Dunning wrote:
But this sounds like a runtime problem, not a type checking problem.
Polymorphism is generally a problem in the Hadoop API. That is why we
have VectorWritable and why I added PolymorphicWritable.
Jeff,
Two questions:
1) would PolymorphicWritable<Cluster> help?
2) can you say more about what the IOException is? Does it give any hints?
On Sun, Feb 12, 2012 at 7:00 AM, Paritosh Ranjan<pran...@xebia.com> wrote:
Can something like this help?
public class CIMapper<T extends Cluster> extends
Mapper<WritableComparable<?>,**VectorWritable,IntWritable,T> {
...
}
On 12-02-2012 06:48, Jeff Eastman wrote:
I'm wondering how to tease the elephant into accepting any concrete
instance of the interface o.a.m.clustering.Cluster when writing trained
clusters in the cleanup() method of CIMapper. I've gotten the MR version of
the ClusterIterator to get to that point in testing but it blows chunks
with an IOException when I try to pass a o.a.m.clustering.kmeans.**Cluster
(I will rename the latter for 0.7). Seems the MapTask.collect() wants ==
and not instanceof.
I've talked with Ted about passing Clusters rather than the current
ClusterObservations but don't see how at this point. Any ideas?
