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https://issues.apache.org/jira/browse/SYSTEMML-1882?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16151620#comment-16151620
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Matthias Boehm commented on SYSTEMML-1882:
------------------------------------------
After a detailed investigation it turns out that the current master branch is
correct, whereas the 0.14 release computed incorrect results. The problematic
statement is the following:
{code}
centroid_placer_raw = table (seq (i, num_centroids * (num_runs - 1) + i,
num_centroids), seq (1, num_runs, 1));
{code}
which SystemML 0.14 incorrectly rewrites to
{code}
--CP ctableexpand _mVar995.MATRIX.DOUBLE _mVar992.MATRIX.DOUBLE
1.0.SCALAR.DOUBLE.true -1.true -1.true _mVar996.MATRIX.DOUBLE false
{code}
while SystemML master correctly compiles it to
{code}
--CP ctable _mVar367.MATRIX.DOUBLE _mVar366.MATRIX.DOUBLE
1.0.SCALAR.DOUBLE.true -1.true -1.true _mVar368.MATRIX.DOUBLE false
{code}
> Perftest: Kmeans shows different behavior compared to previous releases
> -----------------------------------------------------------------------
>
> Key: SYSTEMML-1882
> URL: https://issues.apache.org/jira/browse/SYSTEMML-1882
> Project: SystemML
> Issue Type: Bug
> Reporter: Matthias Boehm
> Priority: Blocker
>
> The current SystemML master shows different convergence behavior on the
> perftest Kmeans scenarios. Triggered by significantly increased execution
> times, a comparison with 0.14 showed the following output (note the different
> number of iterations):
> With SystemML 0.14
> {code}
> Run 1, Iteration 1: Terminated with code = 3, Centroid WCSS =
> 1.1884874830960146E11
> Run 3, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 2, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 7, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 6, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 9, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 8, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 4, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 5, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> Run 10, Iteration 2: Terminated with code = 1, Centroid WCSS =
> 1.1836165397662901E11
> {code}
> With SystemML master:
> {code}
> Run 8, Iteration 12: Terminated with code = 1, Centroid WCSS =
> 1.0897515693466766E11
> Run 4, Iteration 14: Terminated with code = 1, Centroid WCSS =
> 1.0900183622869571E11
> Run 1, Iteration 15: Terminated with code = 1, Centroid WCSS =
> 1.0892913262046584E11
> Run 2, Iteration 16: Terminated with code = 1, Centroid WCSS =
> 1.0893145533814377E11
> Run 6, Iteration 17: Terminated with code = 1, Centroid WCSS =
> 1.0881596327984634E11
> Run 3, Iteration 17: Terminated with code = 1, Centroid WCSS =
> 1.0910103829718127E11
> Run 7, Iteration 20: Terminated with code = 1, Centroid WCSS =
> 1.089467832141638E11
> Run 10, Iteration 20: Terminated with code = 2, Centroid WCSS =
> 1.0873719552339151E11
> Run 5, Iteration 20: Terminated with code = 2, Centroid WCSS =
> 1.0891758743999176E11
> Run 9, Iteration 20: Terminated with code = 2, Centroid WCSS =
> 1.089222095610236E11
> {code}
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