Empty clusters are not that uncommon with k-means if you specify too large a
value for k.

Arshad,  can you say more about what data you are clustering?

On Wed, Mar 31, 2010 at 6:29 AM, Grant Ingersoll <[email protected]>wrote:

> Can you share the parameters you used to get this?  Does it happen every
> time?
>
>
> On Mar 29, 2010, at 11:53 PM, Arshad Khan wrote:
>
> > Hello All
> >
> > While using Mahout 0.3 KMeansDriver I am encountering an exception
> > indicating an empty cluster. This happens sometimes while re-running the
> > clustering on the same data set. Is there a way to prevent this error?
> The
> > exception trace is follows:
> >
> > java.lang.RuntimeException: Error in configuring object
> >        at
> >
> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
> >        at
> > org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
> >        at
> >
> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
> >        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:354)
> >        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307)
> >        at
> > org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:176)
> > Caused by: java.lang.reflect.InvocationTargetException
> >        at sun.reflect.GeneratedMethodAccessor39.invoke(Unknown Source)
> >        at
> >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> >        at java.lang.reflect.Method.invoke(Method.java:597)
> >        at
> >
> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
> >        ... 5 more
> > Caused by: java.lang.RuntimeException: Error in configuring object
> >        at
> >
> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
> >        at
> > org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
> >        at
> >
> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
> >        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:34)
> >        ... 9 more
> > Caused by: java.lang.reflect.InvocationTargetException
> >        at sun.reflect.GeneratedMethodAccessor39.invoke(Unknown Source)
> >        at
> >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> >        at java.lang.reflect.Method.invoke(Method.java:597)
> >        at
> >
> org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
> >        ... 12 more
> > Caused by: java.lang.IllegalStateException: Cluster is empty!
> >        at
> >
> org.apache.mahout.clustering.kmeans.KMeansClusterMapper.configure(KMeansClusterMapper.java:73)
> >        ... 16 more
> >
> > Thanks
> > Arshad
>
> --------------------------
> Grant Ingersoll
> http://www.lucidimagination.com/
>
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