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https://issues.apache.org/jira/browse/MATH-212?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phil Steitz resolved MATH-212.
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Resolution: Fixed
Fixed in r720030 in MATH_2_0 branch. Added copy() to UnivariateStatistics and
StorelessUnivariateStatistics interfaces to ensure implementations support
copying.
> Provide a way to copy all instances of StorelessUnivariateStatistic (e.g.
> Mean, Variance, Max, Kurtoise, etc), perhaps via a copy-constructor
> ---------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: MATH-212
> URL: https://issues.apache.org/jira/browse/MATH-212
> Project: Commons Math
> Issue Type: Improvement
> Environment: N/A
> Reporter: jason
> Assignee: Phil Steitz
> Priority: Minor
> Fix For: 2.0
>
> Attachments: copy_constructor.patch
>
>
> Below is the conversation related to this topic that was posted to the
> Commons Users group. As soon as I figure out how, I'll attach my patch that
> adds copy constructors to all intended classes exception GeometricMean and
> SummaryStatistic, which both allow the user to specify arbitrary
> implementations and thus cannot be copied. See below for details.
> Phil,
> Well, that was easy in some cases and I'm not sure how it went in others and
> could use help. I had issue with creating a copy constructor for
> GeometricMean and SummaryStatistic. Both of these classes allow the user to,
> via the API, set a StorelessUnivariateStatistic as the implementation. For
> instance take the following method in Geometric mean:
> public void setSumLogImpl(
> StorelessUnivariateStatistic sumLogImpl) {
> checkEmpty();
> this.sumOfLogs = sumLogImpl;
> }
> There is no way to create a true deep copy of sumLogImpl, as we only know it
> to be an instance of StorelessUnivariateStatistic. I think the solution is to
> allow the copy constructors for the below classes into the baseline, but not
> provide a copy constructor for GeometricMean or SummaryStatistic unless you
> want to (1) deprecate the implementation business or (2) create a abstract
> copy method in StorelessUnivariateStatistic forcing all implementations to be
> 'copyable'.
> The following classes were able to be given copy constructors without issue:
> Max
> SumOfSquares
> Sum
> Product
> FirstMoment
> SecondMoment
> ThirdMoment
> FourthMoment
> Median
> Min
> SumOfLogs
> Percentile
> Skewness
> Variance
> Mean
> Kurtois
> StandardDeviation
> Phil Steitz wrote:
> > Jason C. HandUber wrote:
> >> Hello,
> >>
> >> I'm writing an evolutionary algorithm in which each individual contains
> >> StandardDeviations and Means. From time to time I need a deep copy / clone
> >> of an individual. Thus far I've actually had to keep a list of all data
> >> and, when cloning, generate a new statistic and increment it with all that
> >> data. Now that I'm moving to production level, turns out I'm running out
> >> of memory (no huge surprise). I'm going to extend Mean, Variance,
> >> StandardDeviation, FirstMoment, and SecondMoment for my application to
> >> provide a copy constructor (which, according to Item 10, page 51 of
> >> Bloch's effective java, beats out clone, and I buy that) for each. Anyway,
> >> I think that addition would be easy and general enough to introduce into
> >> the trunk. Any thoughts?
> > +1 on this enhancement, also for SummaryStatistics, implemented as you
> > describe.
> >
> > Please follow instructions here
> > <http://commons.apache.org/math/developers.html> to create a patch against
> > either trunk or the 2.0 development branch (/branches/MATH_2_0) and attach
> > it to a JIRA ticket.
> >
> > Thanks!
> >
> > Phil
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