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https://issues.apache.org/jira/browse/MATH-384?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12915085#action_12915085
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Phil Steitz commented on MATH-384:
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Looks good. I have a couple of comments, which I will address in the commit if
we agree on them:
1. The addition to DoubleArray interface should only be applied to the 3.0
branch
2. I am not sure we want/need the constructor,
DescriptiveStatistics(ResizeableDoubleArray); the version just taking a
double[] is probably sufficient and better from maintainability and API
simplicity standpoint (in case we ever dump the current internal store).
3. I need to add some tests to confirm, but I don't think the expansion
criteria newSize >= numElements + 1 is correct, unless you first force a
contract(). Remember that there could be unused elements at the beginning of
the array if "rolling" has occurred since the last contraction. I am also
wondering whether you really need to mimic the behavior of expand() in this
method. There is no invariant that says expansion needs to always happen in
lumps as defined by the expansion mode. This machinery is there to eliminate
the need to expand on every single value addition. Seems to me that we could
just shove the new values to the end of the array and update numElements. Am I
missing something?
> DescriptiveStatistics based on double[]
> ---------------------------------------
>
> Key: MATH-384
> URL: https://issues.apache.org/jira/browse/MATH-384
> Project: Commons Math
> Issue Type: New Feature
> Reporter: Mikkel Meyer Andersen
> Priority: Minor
> Fix For: 2.2
>
> Attachments: patch-MATH-384-2, ResizableArrayInstantiatedByArray
>
> Original Estimate: 2h
> Remaining Estimate: 2h
>
> Right now the DescriptiveStatistics is for ResizableDoubleArray, but if the
> user has the double[] data she wishes to get DescriptiveStatistics for there
> is no way of doing this (besides the inefficient way of creating a
> ResizableDoubleArray from the double[]).
> It would be possible to use StatUtils, but it does not contain near as much
> functionality as DescriptiveStatistics.
> Idea: Create a DescriptiveStatistics for double[] also. I'm not sure which
> way of implementing it would be the best, but one way would be to make
> DescriptiveStatistics abstract with all but the apply-method implemented as
> now. The apply-method should be made as abstract which then has to
> implemented in the extensions together with a field containing the values.
> (addValue, windowSize etc. has to go in the ResizableDoubleArray-extension.)
> The double[]-extension should then have a constructor taking double[] as a
> parameter.
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