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From "Gilles (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MATH-1130) A new set of functions for copyof, remove and replace a given value on a slice of array
Date Mon, 23 Jun 2014 13:05:24 GMT

    [ https://issues.apache.org/jira/browse/MATH-1130?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14040715#comment-14040715
] 

Gilles commented on MATH-1130:
------------------------------

bq. "verifyValues" predates the creation of the MathArrays utility class...

Oops. I'm wrong: it is from 3.3!
I have missed it. Otherwise I would have pushed for another syntax. :(

It is possible to deprecate those in 3.4 and switch to the other syntax...

> A new set of functions for copyof, remove and replace a given value on a slice of array
> ---------------------------------------------------------------------------------------
>
>                 Key: MATH-1130
>                 URL: https://issues.apache.org/jira/browse/MATH-1130
>             Project: Commons Math
>          Issue Type: New Feature
>    Affects Versions: 3.4
>            Reporter: Venkatesha Murthy TS
>         Attachments: math-1130.patch
>
>
> These are utility functions mostly required as part of MathArrays.
> MathArrays:
> =============
> The requirement is as follows:
> a) double[] copyOf(double[] values, int begin, int length) ;
> Similar to most other functions that support slice defined  by  the array part from [begin,
begin+length) ;its a requirement to copy a slice which is not available (the closest is copyOf(array,
int len) which misses out the begin index)
> b) double[] removeAll(double[] values, int begin, int length, double removable);
> Need a function to remove a value from array slice defined by [begin,begin+length) and
return the filtered version.
> c) double[] replaceAll(double[] values, int begin, int length, double oldValue, double
newValue);
> Need a function to replace inplace an oldValue substituted with newValue in the array
slice defined by [begin,begin+length) and return the original  complete array with just replaced
values only in the segment [begin,begin+length)
> MathUtils
> =========
> boolean canEqual(double d1, double d2) ;
> provide a canEqual function that is slightly better than exisitng MathUtils.equals. We
could also improve existing equals method however.
> So the change here is that the new enhanced canEqual can do a quick check on Nans and
as well as both +ve and -ve Infinities faster and then move to a detailed Double.compare(..)
method. This avoids the Double.compare call for infinities and NaN with faster reference equal
check (i.e == ).



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