<div dir="ltr">It can't find the solution because you imposed a time limit? Or there is an error? In general, if the parallel version can find a solution, the sequential version should also be able to find one, just in a (possibly much) longer time frame.<div><br></div><div>Variability in running time is expected in parallel mode, since the execution is non-deterministic by default. Cbc does have a deterministic parallel mode, but imposing determinism has a cost. On average, the non-deterministic version will be faster.</div><div><br></div><div>Ted</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jan 30, 2020 at 11:52 AM Rita Portugal <<a href="mailto:rita@siscog.pt" target="_blank">rita@siscog.pt</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div>Thank you for the quick answer.</div>
<div><br>
</div>
<div>Unfortunally when turnning off parallel
runnings CBC can't find the integer solution anymore.</div>
<div><br>
</div>
<div><br>
</div>
<div>On 27/01/2020 22:17, Ted Ralphs wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Are you running in parallel or sequential mode?
Parallel execution can be non-deterministic and may exhibit the
variance you are seeing, depending on the parameters.
<div><br>
</div>
<div>Ted</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Jan 27, 2020 at 12:10
PM Rita Portugal <<a href="mailto:rita@siscog.pt" target="_blank">rita@siscog.pt</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Hi, <br>
</p>
<p>My name is Rita Portugal</p>
<p>I've been working with CBC "inside" C++ language in
Visual Studio framework.</p>
<p>I'm having some strange behavior that I'm hopping you
could help me on understanding it.</p>
<p>I read the input data, create a linear integer model than
call branchAndBound. <br>
</p>
<p>I started by testing a very small example to understand
running time behavior but, while running the same instance
and the same solver configuration several different times
(in the same machine) I'm keep having different time
results for getting the same optimal solution (between 5
minutes to 25).</p>
<p>When reading the user guide I understand that CBC has
random components during is running process that can be
desactivate by the setRandomSeed(7777) comand. But even
doing that the behavior is still the same.</p>
<p>Can you please advise me about any other possible
responsable components for having such a different
behavior between runnings?</p>
<p>Thank you in advance<br>
</p>
<div>-- <br>
<div style="font-family:Arial;font-size:10pt;color:rgb(0,0,0)"><br>
Rita Portugal <br>
<span style="font-size:8pt"> Software Engineer </span>
<br>
<br>
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Cognitivos, SA</b></span> <br>
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1700-097 Lisboa • Portugal <br>
Tel: +351 217 529 100 • Fax: +351 217 529 101<br>
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<div><br>
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-- <br>
<div dir="ltr">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">Dr. Ted Ralphs<br>
Professor, Industrial and Systems Engineering<br>
Lehigh University<br>
(610) 628-1280<br>
ted 'at' lehigh 'dot' edu<br>
<a href="http://coral.ie.lehigh.edu/~ted" target="_blank">coral.ie.lehigh.edu/~ted</a><br>
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<p><br>
</p>
<div>-- <br>
<div style="font-family:Arial;font-size:10pt;color:rgb(0,0,0)"><br>
Rita Portugal <br>
<span style="font-size:8pt">
Software Engineer </span>
<br>
<br>
<span style="font-size:9pt"><b>SISCOG - Sistemas Cognitivos,
SA</b></span> <br>
<span style="font-size:7.5pt"> Campo Grande, 378 - 3º, 1700-097
Lisboa • Portugal <br>
Tel: +351 217 529 100 • Fax: +351 217 529 101<br>
</span>
<br>
<br>
<a href="http://www.siscog.pt" target="_blank"> <span style="font-size:9pt;color:rgb(0,0,0);text-decoration:none"><b>www.siscog.pt</b></span></a>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">Dr. Ted Ralphs<br>Professor, Industrial and Systems Engineering<br>Lehigh University<br>(610) 628-1280<br>ted 'at' lehigh 'dot' edu<br><a href="http://coral.ie.lehigh.edu/~ted" target="_blank">coral.ie.lehigh.edu/~ted</a><br></div></div></div></div></div></div></div></div>