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From "Thomas Neidhart (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MATH-842) Investigate why Bland's rule in Simplex Solver still creates cycles
Date Mon, 16 Sep 2013 12:38:52 GMT

    [ https://issues.apache.org/jira/browse/MATH-842?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13768285#comment-13768285
] 

Thomas Neidhart commented on MATH-842:
--------------------------------------

After a second thought, I think I will just remove the getter/setters again and make the prevention
mechanism the default one for now.
The heuristic with half of the max iterations was just a temporary solution, but with a proper
implementation of Bland's rule it should be obsolete.

                
> Investigate why Bland's rule in Simplex Solver still creates cycles
> -------------------------------------------------------------------
>
>                 Key: MATH-842
>                 URL: https://issues.apache.org/jira/browse/MATH-842
>             Project: Commons Math
>          Issue Type: Improvement
>    Affects Versions: 3.1
>            Reporter: Thomas Neidhart
>            Assignee: Thomas Neidhart
>
> As a consequence of MATH-828, Bland's rule has been introduced to prevent cycling. Now
there are cases where cycles can still occur (see testMath828Cycle in SimplexSolverTest).
These cases have for now been solved with a simple heuristic:
>  * after maxIterations / 2 -> ignore Bland's rule
> This issue has been created to further investigate the problem and come up with a cleaner
solution.

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