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List:       jakarta-commons-dev
Subject:    [jira] Issue Comment Edited: (MATH-351) SimplexSolver fails to
From:       "Mark Thomas (JIRA)" <jira () apache ! org>
Date:       2010-03-31 18:45:27
Message-ID: 1117749376.612211270061127275.JavaMail.jira () brutus ! apache ! org
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    [ https://issues.apache.org/jira/browse/MATH-351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12851930#action_12851930 \
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Mark Thomas edited comment on MATH-351 at 3/31/10 6:44 PM:
-----------------------------------------------------------

Good catch. Not sure how I missed this. I'm still getting an \
UnboundedSolutionException, even after I set the coefficients all to 1, however. Note \
that I'm still using the 2.0 code which was noted above to have a bug in it. Are you \
using 2.1?

Thanks Jurgen!

--Mark

      was (Author: thomamark):
    Good catch--not sure how I missed this. I'm still getting an \
UnboundedSolutionException, even after I set the coefficients all to 1, however. Note \
that I'm still using the 2.0 code which was noted above to have a bug in it--are you \
using 2.1?

Thanks Jurgen!

--Mark
  
> SimplexSolver fails to solve feasible problem instance 
> -------------------------------------------------------
> 
> Key: MATH-351
> URL: https://issues.apache.org/jira/browse/MATH-351
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 2.0
> Environment: Windows Vista Home Premium Version 6.0 Service Pack 1, Build 6001
> Reporter: Mark Thomas
> Fix For: 2.1
> 
> Attachments: SimplexFail.xlsx, TestSimplexFail.java
> 
> 
> SimplexSolver throws an UnboundedSolutionException on a problem instance I can \
> optimally solve with Excel's Solver. I've kept the parameters between the two \
> programs the same as far as I can tell  (i.e. both have a precision/epsilon value \
> of 1e-6 and a maxIterations value of 1000). I will attach a JUnit test  with an \
> example problem on which SimplexSolver fails. I will also attach an Excel \
> spreadsheet wtih the same data and successful Solver setup in place. I don't know a \
> whole lot about linear programming or Simplex, but the problem I'm attempting to \
> solve does appear to have a fairly sparse coefficient matrix, which may be part of \
> the problem. It's surprisingly difficult to find a Java-based linear programming \
> library, so I was ecstatic when I found this. Let me know how I can help! Thanks!

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