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https://issues.apache.org/jira/browse/MAHOUT-1853?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15408387#comment-15408387
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Ted Dunning commented on MAHOUT-1853:
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[~pferrel] Computing the parameters of a normal distribution is definitely
cheaper than updating a t-digest, but I doubt that the difference will be
visible. It takes a few additions and divisions to update the mean and sd,
while it takes 100-200ns on average to update a t-digest with a new sample.
But the big win happens when the data being collected is grossly non-normal, or
when the stuff of interest is an anomalous tail in an otherwise normal
distribution. Both of these cases apply in this situation.
> Improvements to CCO (Correlated Cross-Occurrence)
> -------------------------------------------------
>
> Key: MAHOUT-1853
> URL: https://issues.apache.org/jira/browse/MAHOUT-1853
> Project: Mahout
> Issue Type: New Feature
> Affects Versions: 0.12.0
> Reporter: Andrew Palumbo
> Assignee: Pat Ferrel
> Fix For: 0.13.0
>
>
> Improvements to CCO (Correlated Cross-Occurrence) to include auto-threshold
> calculation for LLR downsampling, and possible multiple fixed thresholds for
> A’A, A’B etc. This is to account for the vast difference in dimensionality
> between indicator types.
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