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https://issues.apache.org/jira/browse/SPARK-16473?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15763324#comment-15763324
]
Alok Bhandari commented on SPARK-16473:
---------------------------------------
[~imatiach] , thanks for showing interest in this issue. I will try to share
the dataset with you , please can you suggest where should I share it ? should
I share it through github? is it fine?
Also , I have tried to diagnose this issue on my own , from my analysis it
looks like , it is failing if it tries to bisect a node which does not have any
children. I also have added a code fix , but not sure if this is the correct
solution :-
*Suggested solution*
{code:BisectingKMeans}
private def updateAssignments(
assignments: RDD[(Long, VectorWithNorm)],
divisibleIndices: Set[Long],
newClusterCenters: Map[Long, VectorWithNorm]): RDD[(Long,
VectorWithNorm)] = {
assignments.map { case (index, v) =>
if (divisibleIndices.contains(index)) {
val children = Seq(leftChildIndex(index), rightChildIndex(index))
if ( children.length>0 ) {
val selected = children.minBy { child =>
KMeans.fastSquaredDistance(newClusterCenters(child), v)
}
(selected, v)
}else {
(index, v)
}
} else {
(index, v)
}
}
}
{code}
*Original code*
{code:BsiectingKMeans}
private def updateAssignments(
assignments: RDD[(Long, VectorWithNorm)],
divisibleIndices: Set[Long],
newClusterCenters: Map[Long, VectorWithNorm]): RDD[(Long,
VectorWithNorm)] = {
assignments.map { case (index, v) =>
if (divisibleIndices.contains(index)) {
val children = Seq(leftChildIndex(index), rightChildIndex(index))
val selected = children.minBy { child =>
KMeans.fastSquaredDistance(newClusterCenters(child), v)
}
(selected, v)
} else {
(index, v)
}
}
}
{code}
> BisectingKMeans Algorithm failing with java.util.NoSuchElementException: key
> not found
> --------------------------------------------------------------------------------------
>
> Key: SPARK-16473
> URL: https://issues.apache.org/jira/browse/SPARK-16473
> Project: Spark
> Issue Type: Bug
> Components: ML, MLlib
> Affects Versions: 1.6.1, 2.0.0
> Environment: AWS EC2 linux instance.
> Reporter: Alok Bhandari
>
> Hello ,
> I am using apache spark 1.6.1.
> I am executing bisecting k means algorithm on a specific dataset .
> Dataset details :-
> K=100,
> input vector =100K*100k
> Memory assigned 16GB per node ,
> number of nodes =2.
> Till K=75 it os working fine , but when I set k=100 , it fails with
> java.util.NoSuchElementException: key not found.
> *I suspect it is failing because of lack of some resources , but somehow
> exception does not convey anything as why this spark job failed.*
> Please can someone point me to root cause of this exception , why it is
> failing.
> This is the exception stack-trace:-
> {code}
> java.util.NoSuchElementException: key not found: 166
> at scala.collection.MapLike$class.default(MapLike.scala:228)
> at scala.collection.AbstractMap.default(Map.scala:58)
> at scala.collection.MapLike$class.apply(MapLike.scala:141)
> at scala.collection.AbstractMap.apply(Map.scala:58)
> at
> org.apache.spark.mllib.clustering.BisectingKMeans$$anonfun$org$apache$spark$mllib$clustering$BisectingKMeans$$updateAssignments$1$$anonfun$2.apply$mcDJ$sp(BisectingKMeans.scala:338)
> at
> org.apache.spark.mllib.clustering.BisectingKMeans$$anonfun$org$apache$spark$mllib$clustering$BisectingKMeans$$updateAssignments$1$$anonfun$2.apply(BisectingKMeans.scala:337)
> at
> org.apache.spark.mllib.clustering.BisectingKMeans$$anonfun$org$apache$spark$mllib$clustering$BisectingKMeans$$updateAssignments$1$$anonfun$2.apply(BisectingKMeans.scala:337)
> at
> scala.collection.TraversableOnce$$anonfun$minBy$1.apply(TraversableOnce.scala:231)
>
> at
> scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:111)
>
> at scala.collection.immutable.List.foldLeft(List.scala:84)
> at
> scala.collection.LinearSeqOptimized$class.reduceLeft(LinearSeqOptimized.scala:125)
>
> at scala.collection.immutable.List.reduceLeft(List.scala:84)
> at
> scala.collection.TraversableOnce$class.minBy(TraversableOnce.scala:231)
> at scala.collection.AbstractTraversable.minBy(Traversable.scala:105)
> at
> org.apache.spark.mllib.clustering.BisectingKMeans$$anonfun$org$apache$spark$mllib$clustering$BisectingKMeans$$updateAssignments$1.apply(BisectingKMeans.scala:337)
>
> at
> org.apache.spark.mllib.clustering.BisectingKMeans$$anonfun$org$apache$spark$mllib$clustering$BisectingKMeans$$updateAssignments$1.apply(BisectingKMeans.scala:334)
>
> at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
> at scala.collection.Iterator$$anon$14.hasNext(Iterator.scala:389)
> {code}
> Issue is that , it is failing but not giving any explicit message as to why
> it failed.
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