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https://issues.apache.org/jira/browse/MATH-655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13095952#comment-13095952
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Gilles commented on MATH-655:
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There are many families of algorithms that have iterative implementations but
also share _other_ basic functionality (like the "solvers" family or the
"optimizers" family). But there is no multiple inheritance in Java; so, an
implementation that would benefit from the boiler-plate code of
{{IterativeAlgorithm}} cannot inherit from it and also from something else
(like a solver base class).
A solution would be that all these families have {{IterativeAlgorithm}} as
their common ancestor; but it would have major (IMHO) drawbacks:
* An implementation detail (e.g. the fact that some root solver performs
iterations) becomes most prominent.
* Some specific implementations that could in fact be "non-iterative" would
nevertheless look like they are.
So, how did you intend to plug {{IterativeAlgorithm}} into the design?
The presence of a "protected" method like {{resetIterationCount}} means that it
is to be inherited from (i.e. the above "solution").
> General framework for iterative algorithms
> ------------------------------------------
>
> Key: MATH-655
> URL: https://issues.apache.org/jira/browse/MATH-655
> Project: Commons Math
> Issue Type: New Feature
> Affects Versions: 3.0
> Reporter: Sébastien Brisard
> Priority: Minor
> Labels: algorithm, events
> Attachments: iterative-algorithm.zip
>
>
> Following the thread [Monitoring iterative
> algorithms|http://mail-archives.apache.org/mod_mbox/commons-dev/201108.mbox/%3CCAGRH7HrgcgoBA=jcoKovjiQU=TjpQHnspBkOGNCu7oDdKk=k...@mail.gmail.com%3E],
> here is a first attempt at defining a general enough framework for iterative
> algorithms at large. At the moment, the classes provide support for
> * maximum number of iterations
> * events handling
> ** initialization event (prior to entering the main loop),
> ** iteration event (after completion of one iteration),
> ** termination event (after termination of the main loop).
> These classes do not yet provide support for a stopping criterion.
> Some points worth to note
> * For the time being, the classes are part of the o.a.c.m.linear package.
> * For the time being, {{IterativeAlgorithm.incrementIterationCount()}} throws
> a {{TooManyEvaluationsException}}. If the proposed new feature is integrated
> into CM, then a proper {{TooManyIterationsException}} should be created, from
> which the former could derive.
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