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Posted to dev@hama.apache.org by "Martin Illecker (JIRA)" <ji...@apache.org> on 2014/01/05 15:08:51 UTC
[jira] [Comment Edited] (HAMA-834) Fix KMeans example
[ https://issues.apache.org/jira/browse/HAMA-834?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13862259#comment-13862259 ]
Martin Illecker edited comment on HAMA-834 at 1/5/14 2:08 PM:
--------------------------------------------------------------
Please see the updated patch.
You have to compare double values:
{code}
- assertTrue(doubleVector.get(0) >= 50 && doubleVector.get(0) < 51);
- assertTrue(doubleVector.get(1) >= 50 && doubleVector.get(1) < 51);
+ assertEquals(Double.valueOf(50), doubleVector.get(0));
+ assertEquals(Double.valueOf(50), doubleVector.get(1));
{code}
{quote}
What do you mean exactly?
{quote}
Finally I want to verify the result for a different amount of *NumBspTask*.
Therefore I set the *NumBspTask* within TestKMeansBSP.
{code}
+ job.setNumBspTask(3);
+ System.out.println("NumBspTask: " + job.getNumBspTask());
{code}
But *LAUNCHED_TASK* stays always one?
was (Author: bafu):
Please see the updated patch.
You have to compare double values:
{code}
- assertTrue(doubleVector.get(0) >= 50 && doubleVector.get(0) < 51);
- assertTrue(doubleVector.get(1) >= 50 && doubleVector.get(1) < 51);
+ assertEquals(Double.valueOf(50), doubleVector.get(0));
+ assertEquals(Double.valueOf(50), doubleVector.get(1));
{code}
BTW why do we need 101 input vectors not 100?
{code}
- for (int i = 0; i < 100; i++) {
+ for (int i = 0; i < 101; i++) {
{code}
The resulting center of 100 input vectors would be (49.5, 49.5).
{quote}
What do you mean exactly?
{quote}
Finally I want to verify the result for a different amount of *NumBspTask*.
Therefore I set the *NumBspTask* within TestKMeansBSP.
{code}
+ job.setNumBspTask(3);
+ System.out.println("NumBspTask: " + job.getNumBspTask());
{code}
But *LAUNCHED_TASK* stays always one?
> Fix KMeans example
> ------------------
>
> Key: HAMA-834
> URL: https://issues.apache.org/jira/browse/HAMA-834
> Project: Hama
> Issue Type: Bug
> Components: examples, machine learning
> Affects Versions: 0.6.3
> Reporter: Martin Illecker
> Labels: example
> Fix For: 0.7.0
>
> Attachments: HAMA-834.patch
>
>
> Fix problems in KMeans example and revise test case.
> 1) Typo \[1] and input path issue
> 2) Wrong *summationCount* in assignCentersInternal
> *summationCount* should also be incremented if \[2]
> {code}
> if (clusterCenter == null) {
> newCenterArray[lowestDistantCenter] = key;
> }
> {code}
> Otherwise *summationCount* may stay zero when only one value is assigned. Then this zero will be propagated to *incrementSum* \[3] and might cause a divide by zero in \[4].
> By the way if we add three vectors and the *summationCount* would only be two, this will lead to wrong results. Because later we are dividing the vector by the amount of increments.
> 3) Results depend on the amount *numBspTask*
> (results vary if *numBspTask* is changed)
> \[1]
> https://github.com/apache/hama/blob/trunk/ml/src/main/java/org/apache/hama/ml/kmeans/KMeansBSP.java#L518-519
> \[2] https://github.com/apache/hama/blob/trunk/ml/src/main/java/org/apache/hama/ml/kmeans/KMeansBSP.java#L249
> \[3]
> https://github.com/apache/hama/blob/trunk/ml/src/main/java/org/apache/hama/ml/kmeans/KMeansBSP.java#L161
> \[4] https://github.com/apache/hama/blob/trunk/ml/src/main/java/org/apache/hama/ml/kmeans/KMeansBSP.java#L172
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