The SparkEngine colCounts functions was checking for >= 0. But because it was 
iterating nonZero it never got an == 0, so a bug that didn’t surface. It’s 
already been fixed.

The primary question at present is: what should we call colCounts? Currently it 
is used in cooccurrence:

    val bcastInteractionsPerItemA = drmBroadcast(drmA.colCounts)

Dmitriy wanted you to see if this fits R-Like semantics and suggest an 
alternative, if possible. I was commenting on the possible Java related naming 
so ignore any misstatements.

On Jun 12, 2014, at 9:50 AM, Sebastian Schelter <s...@apache.org> wrote:

I'm a bit lost in this discussion. Why do we assume that 
getNumNonZeroElements() on a Vector only returns an upper bound? The code in 
AbstractVector clearly returns the non-zeros only:

   int count = 0;
   Iterator<Element> it = iterateNonZero();
   while (it.hasNext()) {
     if (it.next().get() != 0.0) {
       count++;
     }
   }
   return count;

On the other hand, the internal code seems broken here, why does iterateNonZero 
potentially return 0's?

--sebastian





On 06/12/2014 06:38 PM, ASF GitHub Bot (JIRA) wrote:
> 
>     [ 
> https://issues.apache.org/jira/browse/MAHOUT-1464?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14029345#comment-14029345
>  ]
> 
> ASF GitHub Bot commented on MAHOUT-1464:
> ----------------------------------------
> 
> Github user dlyubimov commented on the pull request:
> 
>     https://github.com/apache/mahout/pull/12#issuecomment-45915940
> 
>     fix header to say MAHOUT-1464, then hit close and reopen, it will restart 
> the echo.
> 
> 
>> Cooccurrence Analysis on Spark
>> ------------------------------
>> 
>>                 Key: MAHOUT-1464
>>                 URL: https://issues.apache.org/jira/browse/MAHOUT-1464
>>             Project: Mahout
>>          Issue Type: Improvement
>>          Components: Collaborative Filtering
>>         Environment: hadoop, spark
>>            Reporter: Pat Ferrel
>>            Assignee: Pat Ferrel
>>             Fix For: 1.0
>> 
>>         Attachments: MAHOUT-1464.patch, MAHOUT-1464.patch, 
>> MAHOUT-1464.patch, MAHOUT-1464.patch, MAHOUT-1464.patch, MAHOUT-1464.patch, 
>> run-spark-xrsj.sh
>> 
>> 
>> Create a version of Cooccurrence Analysis (RowSimilarityJob with LLR) that 
>> runs on Spark. This should be compatible with Mahout Spark DRM DSL so a DRM 
>> can be used as input.
>> Ideally this would extend to cover MAHOUT-1422. This cross-cooccurrence has 
>> several applications including cross-action recommendations.
> 
> 
> 
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