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From "Ben McCann (JIRA)" <j...@apache.org>
Subject [jira] Commented: (MATH-246) Simplex Method Implementation
Date Thu, 26 Mar 2009 16:39:58 GMT

    [ https://issues.apache.org/jira/browse/MATH-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12689539#action_12689539
] 

Ben McCann commented on MATH-246:
---------------------------------

That constructor was made so that constraints such as x + 2y <= 3x + 4y could be expressed
instead of just scalars on the right hand side (x + 2y <= 9).  The user doesn't have to
care about the implementation details which cause one side to be subtracted from the other,
but only needs to know how to express their constraint.  I actually would propose a different
change to the constructor, which would be to change it to:
public LinearEquation(RealVector leftHandSide, double lhsConstantTerm, Relationship relationship,
RealVector rightHandSide, double rhsConstantTerm)
That would make it more flexible and allow for constraints such as x + 2y + 7 <= 3x + 4y
+ 6 which I originally overlooked.  You're correct that the user could do this him/herself,
but it seems a common use case (one I will be using frequently to say the least), so I thought
it wise to provide the extra convenience.
And perhaps adding some JavaDocs would clear up any potential confusion that I had not envisioned:
/**
 * @param leftHandSide The coefficients of the linear expression on the left hand side of
the constraint
 * @param lhsConstantTerm The constant term of the linear expression on the left hand side
of the constraint
 * @param relationship The type of (in)equality used in the constraint
 * @param rightHandSide The coefficients of the linear expression on the right hand side of
the constraint
 * @param rhsConstantTerm The constant term of the linear expression on the right hand side
of the constraint
 */

> 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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