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From "Phil Steitz (JIRA)" <j...@apache.org>
Subject [jira] Closed: (MATH-314) New sparse vector implementation: int[] indices; double[] values;
Date Sat, 03 Apr 2010 20:51:29 GMT

     [ https://issues.apache.org/jira/browse/MATH-314?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Phil Steitz closed MATH-314.
----------------------------


> New sparse vector implementation: int[] indices; double[] values;
> -----------------------------------------------------------------
>
>                 Key: MATH-314
>                 URL: https://issues.apache.org/jira/browse/MATH-314
>             Project: Commons Math
>          Issue Type: New Feature
>    Affects Versions: 2.0
>         Environment: all
>            Reporter: Jake Mannix
>            Priority: Minor
>             Fix For: 2.1
>
>
> OpenMapRealVector is nice for fast random access, but if all you do with your sparse
vectors is dot them together, add them onto dense vectors, and so forth, the representation
as just an array of indices and an array of values is more compact, and faster (for these
operations).  
> It becomes prohibitive to do modification, however, so the usual thing is to have them
be immutable - use an OpenMapRealVector while modifing, then seal them up into the constructor
for an IntDoubleArrayVector form for fast iteration and so forth.

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