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https://issues.apache.org/jira/browse/MAHOUT-1560?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jarosław Bojar updated MAHOUT-1560:
-----------------------------------
Description:
In {{MultithreadedBatchItemSimilarities}} method {{queueItemIDsInBatches}}
handles last batch incorrectly. Last batch length is calculated incorrectly. As
a result last batch is either truncated or too long with superfluous positions
filled with item indexes from previous batch (or zeros if it is also the first
batch as in attached test).
Attached test fails for very short model (with only 4 items) with
NoSuchItemException.
Attached patch corrects this issue.
was:
In {{MultithreadedBatchItemSimilarities}} method {{queueItemIDsInBatches}}
handles last batch incorrectly. Last batch length is calculated incorrectly. As
a result last batch is either truncated or too long with superfluous positions
filled with item indexes from previous batch.
Attached test fails for very short model (with only 4 items) with
NoSuchItemException.
Attached patch corrects this issue.
> Last batch is not filled correctly in MultithreadedBatchItemSimilarities
> ------------------------------------------------------------------------
>
> Key: MAHOUT-1560
> URL: https://issues.apache.org/jira/browse/MAHOUT-1560
> Project: Mahout
> Issue Type: Bug
> Components: Collaborative Filtering
> Affects Versions: 0.9
> Reporter: Jarosław Bojar
> Priority: Minor
> Attachments: Corrected_last_batch_size_calculation.patch,
> MultithreadedBatchItemSimilaritiesTest.patch
>
>
> In {{MultithreadedBatchItemSimilarities}} method {{queueItemIDsInBatches}}
> handles last batch incorrectly. Last batch length is calculated incorrectly.
> As a result last batch is either truncated or too long with superfluous
> positions filled with item indexes from previous batch (or zeros if it is
> also the first batch as in attached test).
> Attached test fails for very short model (with only 4 items) with
> NoSuchItemException.
> Attached patch corrects this issue.
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