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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">John,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Sure that this problem is very tricky.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I wrote a Python script launching cbc until the solution file is different from a reference solution.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">According to these tests, cbc must be ran (on the same machine) between 1 and 200 times before failing (mean is around 50).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Yves<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></a></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"> John Forrest [mailto:john.forrest@fastercoin.com]
<br>
<b>Sent:</b> Monday, February 08, 2016 5:34 PM<br>
<b>To:</b> Yves Touchard <ytouchard@gopro.com>; cbc@list.coin-or.org<br>
<b>Subject:</b> Re: [Cbc] Non Deterministic solution<o:p></o:p></span></p>
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<p class="MsoNormal">Yves,<br>
<br>
Difficult to debug this. I have run it a hundred times and got the same answer each time.<br>
<br>
John<br>
<br>
On 08/02/16 12:11, Yves Touchard wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">John,<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">I did the changes (two lines in ClpSimplex.cpp) and there is still determinism problems.<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">Yves<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b>From:</b>
<a href="mailto:john.forrest@fastercoin.com">john.forrest@fastercoin.com</a> [<a href="mailto:john.forrest@fastercoin.com">mailto:john.forrest@fastercoin.com</a>]
<br>
<b>Sent:</b> Friday, February 05, 2016 5:33 PM<br>
<b>To:</b> Yves Touchard <a href="mailto:ytouchard@gopro.com"><ytouchard@gopro.com></a>;
<a href="mailto:cbc@list.coin-or.org">cbc@list.coin-or.org</a><br>
<b>Subject:</b> RE: [Cbc] Non Deterministic solution<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Yves,<br>
<br>
My guess is that it is because there are places where CoinDrand48 is used. <br>
<br>
Most likely is in ClpSimplex.cpp - try changing<br>
<br>
Coindrand48()<br>
<br>
to<br>
<br>
randomNumberGenerator_.randomDouble()<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">if that fixes I will check change in<br>
<br>
<br>
John<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">-------- Original Message --------<br>
Subject: [Cbc] Non Deterministic solution<br>
From: Yves Touchard <<a href="mailto:ytouchard@gopro.com">ytouchard@gopro.com</a>><br>
Date: Thu, February 04, 2016 11:31 am<br>
To: "<a href="mailto:cbc@list.coin-or.org">cbc@list.coin-or.org</a>" <<a href="mailto:cbc@list.coin-or.org">cbc@list.coin-or.org</a>><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="FR">Hello,</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="FR"> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I have just a got a determinism problem with a constraint file:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">You will find at
<a href="https://www.dropbox.com/s/uzbmgj48kvtd5yj/pb.tar.gz?dl=0">https://www.dropbox.com/s/uzbmgj48kvtd5yj/pb.tar.gz?dl=0</a>, a tar file containing five files:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">· pb.lp is the constraint file.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">· pbTriv.sol is a solution file of the trivial problem (same problem with relaxed constraints) used for mipstart.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">· pb.prio is the priority file.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">· pbCmd1.sol is the most frequent solution provided by coin.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">· pbCmd1Alt.sol is the alternative solution (not easy to catch it…).<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Command line is:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">bin/cbc pb.lp threads 104 ratio 0.05 mipstart pbTriv.sol priority pb.prio divingP on divingV on divesolves 301 multiple 4 branch printingOptions normal solution pb.sol<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Cbc coin is 2.9.7 rev:2232 compiled with gcc 4.9.0<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Could you have a look on it, please?<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thanks<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Yves<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">_______________________________________________<br>
Cbc mailing list<br>
<a href="mailto:Cbc@list.coin-or.org">Cbc@list.coin-or.org</a><br>
<a href="http://list.coin-or.org/mailman/listinfo/cbc">http://list.coin-or.org/mailman/listinfo/cbc</a><o:p></o:p></p>
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