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https://issues.apache.org/jira/browse/MATH-231?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Luc Maisonobe resolved MATH-231.
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Resolution: Fixed
fixed in trunk as of r724141
> User-extendable Abstract RealMatrix implementation
> --------------------------------------------------
>
> Key: MATH-231
> URL: https://issues.apache.org/jira/browse/MATH-231
> Project: Commons Math
> Issue Type: New Feature
> Affects Versions: 2.0
> Environment: Any
> Reporter: Sujit Pal
> Assignee: Luc Maisonobe
> Priority: Minor
> Fix For: 2.0
>
>
> Many algorithms are described using Matrices. In some situations, the
> Matrices for applications are too large to fit into memory, so it makes sense
> to use custom implementations that are backed by a sparse map or list, or
> backed by Lucene indexes or database tables, etc. This allows the algorithm
> implementations (in the application) to be clean and mimic the algorithm
> itself, making it easy to understand and debug.
> However, the only way to make a custom implementation currently is to
> implement RealMatrix, and to implement all its methods, or to extend and
> override methods in RealMatrixImpl. The former involves a knowledge of matrix
> operations, which is not guaranteed for people who are business programmers
> (which may be the reason they are using commons-math in the first place). The
> latter involves looking at the existing code and making the overrides where
> needed, again something that is not expected from a commons-math user. A
> simpler way would be to have something generic mostly built, except the
> getEntry() and setEntry() methods which would be declared abstract and hence
> meant to be overriden, and all the other methods to be pre-built based on
> getEntry() and setEntry().
> This would make the creation of custom matrices very flexible, and would also
> remove the burden of providing "common matrix impls" from the commons-math
> project, since clients can very simply create custom versions of their own.
> I suggest the following:
> <<RealMatrix.java>> <-- RealMatrixImpl
> <-- (AbstractRealMatrixImpl)
> The SparseRealMatrixImpl I contributed in MATH-230 could be a user-defined
> custom subclass of AbstractRealMatrixImpl and not have to belong to the
> commons-math project at all. Or it could be included as an example if there
> is enough need.
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