commons-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Richard Brunauer (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (MATH-1347) Wrong equation in Javadoc of Percentile.EstimationType, LAGACY, variable estimation
Date Mon, 21 Mar 2016 12:03:25 GMT

    [ https://issues.apache.org/jira/browse/MATH-1347?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15204081#comment-15204081
] 

Richard Brunauer edited comment on MATH-1347 at 3/21/16 12:02 PM:
------------------------------------------------------------------

No, I can’t provide a junit test. The mistake is in Javadoc and not in Java code. The results
are, for my opinion, correct. 

I guess that the explanation is correct but the equation does not represent the explanation’s
semantics. Explanation and expression are semantically not equal! 

Explaination in Percentile for the default/legacy case: “Else let lower be the element in
position floor(pos) in the array and let upper be the next element in the array. Return lower
+ d * (upper - lower)”

Equation in Percentile.EstimationType: x[ceil(h - 1/2)]

I would expect the same equation for variable “estimate” as in R_6. Furthermore, the Percentile.EstimationType
“R_6” and “LAGACY” is almost a code copy (compare method index()).Is this intended?


To see the mistake:
https://commons.apache.org/proper/commons-math/apidocs/org/apache/commons/math3/stat/descriptive/rank/Percentile.EstimationType.html
section: Enum Constant Detail
enum: LEGACY 



was (Author: richard.brunauer@salzburgresearch.at):
No, I can’t provide a junit test. The mistake is in Javadoc and not in Java code. The results
are, for my opinion, correct. 

I guess that the explanation is correct but the equation does not represent the explanation’s
semantics. Explanation and expression are semantically not equal! 

Explaination in Percentile for the default/legacy case: “Else let lower be the element in
position floor(pos) in the array and let upper be the next element in the array. Return lower
+ d * (upper - lower)”

Equation in Percentile.EstimationType: x[ceil(h - 1/2)]

I would expect the same equation for variable “estimate” as in R_6. Furthermore, the Percentile.EstimationType
“R_6” and “LAGACY” is almost a code copy (compare method index()).Is this intended?


To see the mistake:
https://commons.apache.org/proper/commons-math/apidocs/org/apache/commons/math3/stat/descriptive/rank/Percentile.EstimationType.html
section: Enum Constant Detail
enum: LAGACY 


> Wrong equation in Javadoc of Percentile.EstimationType, LAGACY, variable estimation
> -----------------------------------------------------------------------------------
>
>                 Key: MATH-1347
>                 URL: https://issues.apache.org/jira/browse/MATH-1347
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 3.6
>         Environment: Windows 7
>            Reporter: Richard Brunauer
>            Priority: Trivial
>              Labels: documentation
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> The Javadoc entry for Enum Percentile.EstimationType LAGACY uses a wrong equation for
variable estimate. 
> Explaination in version 3.0, 3.6 source code and 3.6 semantics do an interpolation between
two values. The quation for variable estimation has only a ceiling function. This does not
match. 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message