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Date: Tue, 31 May 2016 12:16:12 +0000 (UTC)
From: "Ryan Gaffney (JIRA)" <jira@apache.org>
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Subject: [jira] [Comment Edited] (MATH-1370) Increase efficiency of
 EnumeratedDistribution#probability
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archived-at: Tue, 31 May 2016 12:16:14 -0000


    [ https://issues.apache.org/jira/browse/MATH-1370?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15307633#comment-15307633 ] 

Ryan Gaffney edited comment on MATH-1370 at 5/31/16 12:15 PM:
--------------------------------------------------------------

Had a couple nit comments, besides that looks good. Thanks!


was (Author: rg_):
Had one nit comment, besides that looks good. Thanks!

> Increase efficiency of EnumeratedDistribution#probability
> ---------------------------------------------------------
>
>                 Key: MATH-1370
>                 URL: https://issues.apache.org/jira/browse/MATH-1370
>             Project: Commons Math
>          Issue Type: Improvement
>            Reporter: Ryan Gaffney
>            Priority: Minor
>              Labels: patch, performance
>         Attachments: enum-distribution-perf-patch, enum-distribution-perf-patch.2
>
>
> There are lots of other low hanging fruit in the distribution package but unfortunately this is the only one I got to that day.
> In the EnumeratedDistribution case, the probability() method is currently O(N) where N denotes number of random variables, even though the random variables are fixed / known. This change makes probability() O(1). The unlikely worst case scenario now consumes slightly more than 2x the memory, but I do not think this would be an issue in the vast majority of cases.
> Original PR (incorrectly against master) [here|https://github.com/apache/commons-math/pull/34].


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