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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#44546A">Thanks Ted.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#44546A"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#44546A">I attached my MPS file. p.s. I also attached the same problem in LP format. Thanks!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#44546A"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Lu<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#44546A"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Ted Ralphs [mailto:ted@lehigh.edu]
<br>
<b>Sent:</b> Wednesday, March 08, 2017 3:01 PM<br>
<b>To:</b> Liu, Lu <Lu.Liu@fisglobal.com><br>
<b>Cc:</b> cbc@list.coin-or.org<br>
<b>Subject:</b> Re: [Cbc] cbc solver<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">If you post the MPS file, I'm sure someone will be able to help.<o:p></o:p></p>
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<p class="MsoNormal">Ted<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Wed, Mar 8, 2017 at 7:53 PM, Liu, Lu <<a href="mailto:Lu.Liu@fisglobal.com" target="_blank">Lu.Liu@fisglobal.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#44546A">Hi,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#44546A"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#44546A">I created a MPS file for my problem and I have tried CBC solver via the command line and also CPLEX via an online solver. CBC returned “ problem is unbounded”
error, but CPLEX is able to give me a solution and the solution obeys the constraints. I wonder if this is a limitation of CBC. In addition, in the CBC command window, I also found that it says:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#44546A"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Problem SOLVER_TEST has 26 rows, 32 columns and 118 elements<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">but in my problem, I only have 25 columns, I find this suspicious. Could it be my MPS file formatting problem which leads the solver to think there are 32 variables? When I tweak
the objective function and tried to make it bound, I got a solution like below:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X1<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X2<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X2<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X3<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X3<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">…<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X8<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X8<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X9<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">X10<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Clearly it seems to treat some of my variables as duplicates, can someone help? Thanks!<o:p></o:p></p>
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<p class="MsoNormal">The information contained in this message is proprietary and/or confidential. If you are not the intended recipient, please: (i) delete the message and all copies; (ii) do not disclose, distribute or use the message in any manner; and (iii)
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<o:p></o:p></p>
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-- <o:p></o:p></p>
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<p class="MsoNormal">Dr. Ted Ralphs<br>
Visiting Researcher, Zuse Institute Berlin<br>
Professor, Lehigh University<br>
(610) 628-1280<br>
ted 'at' lehigh 'dot' edu<br>
<a href="https://emea01.safelinks.protection.outlook.com/?url=http:%2F%2Fcoral.ie.lehigh.edu%2F~ted&data=01%7C01%7CLu.Liu%40fisglobal.com%7Cd8e3eb3744194f10c9e808d4665e00f5%7Ce3ff91d834c84b15a0b418910a6ac575%7C0&sdata=4lZSbEwQsEZh%2BH7RJUkWUHYsUeL1QhxiHj%2Fn0TZ7LJc%3D&reserved=0" target="_blank">coral.ie.lehigh.edu/~ted</a><o:p></o:p></p>
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