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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am using latest version of cbc (Cbc-2.10.3-win32-msvc15).<o:p></o:p></p>
<p class="MsoNormal">I sometimes meet a very strange behavior when using it.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For example, with the data attached and the following command line :<o:p></o:p></p>
<p class="MsoNormal">cbc.exe "Model.mps" -preprocess off -ratio 1E-05 -seconds 30 -minimize -solve -printingOptions all -solution "solution.txt"<o:p></o:p></p>
<p class="MsoNormal">It stops after 30 seconds telling either the problem is infeasible (Result - Problem proven infeasible), either it reaches the time limit (Result - Stopped on time limit).<o:p></o:p></p>
<p class="MsoNormal">In both cases, the objective value seems very strange and the solution is not valid (some binary variables are not 0 or 1).<o:p></o:p></p>
<p class="MsoNormal">But when I read the log, it seems that some integer solutions have been found so I do not understand the final result.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">When I increase the max time to 60 seconds, problem is solved : Result - Optimal solution found.<o:p></o:p></p>
<p class="MsoNormal">I attached the different log files.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In the past, I had similar issues with previous versions like 2.9.8. I had to downgrade to 2.8.13 to avoid them.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I know that setting “on” the preprocess allow to avoid this in that case but I do not want to do it for some other reasons.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">If someone know how to avoid this, it would be great !<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Nicolas<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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