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https://issues.apache.org/jira/browse/MAHOUT-1157?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13598630#comment-13598630
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Sebastian Schelter commented on MAHOUT-1157:
--------------------------------------------
Thanks for pointing us, there are much more problems in that code...
{code}
int nzero = 0;
Iterator<Vector.Element> iterateNonZero = v.iterateNonZero();
while (iterateNonZero.hasNext()) {
iterateNonZero.next();
nzero++;
}
{code}
can be replaced by v.getNumNonDefaultElements() for example...
> AbstractCluster.formatVector iteration bug.
> -------------------------------------------
>
> Key: MAHOUT-1157
> URL: https://issues.apache.org/jira/browse/MAHOUT-1157
> Project: Mahout
> Issue Type: Bug
> Components: Clustering
> Affects Versions: 0.7
> Reporter: Adam Bozanich
> Attachments: mahout.patch
>
>
> AbstractCluster.formatVector's use of the size field of the given vector
> causes problems when the vector is sparse.
> I clustered a handful of vectors which had been initialized with a
> cardinality of Integer.MAX_VALUE. Running seqdump on the resulting
> clusteredPoints took over four minutes. This is because formatVector() was
> iterating over the entire integer space for every vector.
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