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From "Luc Maisonobe (JIRA)" <j...@apache.org>
Subject [jira] Commented: (MATH-246) Simplex Method Implementation
Date Thu, 26 Mar 2009 07:57:51 GMT

    [ https://issues.apache.org/jira/browse/MATH-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12689389#action_12689389
] 

Luc Maisonobe commented on MATH-246:
------------------------------------

Another issue that bothers me.
There is a constructor for a linear constraint with vectors for both left hand side and right
hand side that subtracts both and put 0 as the scalar on the right hand side.
This seems odd to me.
If for example we call it with lhs = { 2, 3 }, rhs = { 1, 1 }, r = EQ this means we set up
the constraint
(2 - 1) x + (3 - 1)y = 0 or x + 2y = 0. Users may think it would be equivalent to the two
constraints 2x=1 and 3y=1 which is not the case. For inequality constraints, this looks even
more strange.
If there is a use for this in a specific context, I suggest the subtraction be done at user
code level before calling the constructor rather than providing support in the linear constraint
class for this.
I suggest to drop this constructor, except if you can provide me some hints I will pour in
the javadoc to help users.

> Simplex Method Implementation
> -----------------------------
>
>                 Key: MATH-246
>                 URL: https://issues.apache.org/jira/browse/MATH-246
>             Project: Commons Math
>          Issue Type: New Feature
>            Reporter: Benjamin McCann
>            Assignee: Luc Maisonobe
>             Fix For: 2.0
>
>         Attachments: newfiles.zip
>
>
> I've created an implementation of the Simplex algorithm for optimizing systems of constrained
linear equations that I'd like to contribute.

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