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From "Vipul Pandey (JIRA)" <j...@apache.org>
Subject [jira] Issue Comment Edited: (MAHOUT-617) FPGrowth/PFPGrowth giving out wrong results.
Date Sun, 13 Mar 2011 19:37:59 GMT

    [ https://issues.apache.org/jira/browse/MAHOUT-617?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13006263#comment-13006263
] 

Vipul Pandey edited comment on MAHOUT-617 at 3/13/11 7:36 PM:
--------------------------------------------------------------

yes, exactly. But the output that I get upon running FPGrowth on the input file for support
11 is as below : 

12 X 
11 X Y Z 

isn't that what you are getting too?

and this is what I get for for support = 1

12 X 
10 X Y 
11 X Y Z 
4 Y 

      was (Author: vipandey):
    yes, exactly. But the output that I get upon running FPGrowth on the input file for support
11 is as below : 

12 X 
11 X Y Z 

isn't that what you are getting too?

and this is for support = 1

12 X 
10 X Y 
11 X Y Z 
4 Y 
  
> FPGrowth/PFPGrowth giving out wrong results. 
> ---------------------------------------------
>
>                 Key: MAHOUT-617
>                 URL: https://issues.apache.org/jira/browse/MAHOUT-617
>             Project: Mahout
>          Issue Type: Bug
>          Components: Frequent Itemset/Association Rule Mining
>    Affects Versions: 0.4
>         Environment: Mac OS X, Linux
>            Reporter: Vipul Pandey
>            Assignee: Robin Anil
>              Labels: AssociationMining, FPGrowth, FrequentItemsets
>         Attachments: XY, XYZ
>
>
> FPGrowth reports the support of itemsets individually - in that - if Item X appears "individually"
12 times and appears with item Y 10 times (a total of 22 times) AND item Y appears "individually"
4 times (a total of 14 times) then this is what the output will be (say for min-support 2)
> 12 X
> 10 XY
> 4  Y
> Instead of 
> 22 X
> 10 XY
> 14 Y
> Also, because of this If the minimum support is 5 then the output will look like : 
> 12 X
> 10 X Y
> Thus totally Ignoring Y
> if the minimum support is 11 then the output will look like 
> 12 X
> again Ignoring Y
> if the minimum support is 13 then there will be NO output. even though all the way along
Xs support was 22 and Y's was 14
> Even if we want to show just the maximal itemsets (although i would like to see ALL the
frequent itemsets - maximal or not) this output is wrong as with a support of 13 we should
still have seen X(22) and Y(14)
> Now Say you add XYZ 11 times
> for support 1 you'd see
> 12 X
> 10 X Y
> 11 X Y Z
> 4   Y
> And for support 11 you'd see
> 12 X
> 11 X Y Z
> Although I'd expect the output (for both s=1 & s=11) to be 
> 33 X
> 25 Y 
> 21 XY
> 11 Z
> 11 XZ
> 11 YZ
> 11 XYZ
> attached are the sample inputs: 

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