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https://issues.apache.org/jira/browse/MATH-290?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Benjamin McCann updated MATH-290:
---------------------------------

    Attachment: SimplexSolverTest.patch
                SimplexTableau.patch

My earlier comments were misleading.  I misread the example provided (I need 
more sleep!).  The original patch is sufficient.  I'm attaching a new one that 
also cleans up some code formatting (weird spacing in SimplexTableau) and also 
provides a little bit better test.
Andrea, the correct solution for the example you provided is 0.  You restricted 
the variables to be non-negative and are trying to minimize the objective 
function, so the best you can do is make both variables 0 for an objective 
function value of 0.

> NullPointerException in SimplexTableau.initialize
> -------------------------------------------------
>
>                 Key: MATH-290
>                 URL: https://issues.apache.org/jira/browse/MATH-290
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 2.0
>         Environment: Java 1.6.0_13 on Windows XP 32-bit 
>            Reporter: Andrea
>         Attachments: SimplexSolverTest.patch, SimplexTableau.patch
>
>
> SimplexTableau throws a NullPointerException when no solution can be found 
> instead of a NoFeasibleSolutionException
> Here is the code that causes the NullPointerException:
> LinearObjectiveFunction f = new LinearObjectiveFunction(new double[] { 1, 5 
> }, 0 );
> Collection<LinearConstraint> constraints = new ArrayList<LinearConstraint>();
> constraints.add(new LinearConstraint(new double[] { 2, 0 }, Relationship.GEQ, 
> -1.0));
> RealPointValuePair solution = new SimplexSolver().optimize(f, constraints, 
> GoalType.MINIMIZE, true);
> Note: Tested both with Apache Commons Math 2.0 release and SVN trunk

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