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<div class="moz-cite-prefix">Marcel,<br>
<br>
I can get a similar error using 2.7.5. I have also tried 2.7.8
and that was fine. I would suggest upgrading to at least 2.7.8.<br>
<br>
John Forrest<br>
On 18/04/13 11:53, Marcel Hunting wrote:<br>
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<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">I
have a small MIP problem for which CBC 2.7.5 returns
infeasible while the problem is in fact feasible. This is
part of the log file:<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Optimal
- objective value 5625.1701<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Integer
solution of -5625.1701 found by feasibility pump after 0
iterations and 0 nodes (0.17 seconds)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Objective
coefficients multiple of 0.1<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Search
completed - best objective -5625.170085470087, took 0
iterations and 0 nodes (0.18 seconds)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Maximum
depth 0, 0 variables fixed on reduced cost<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">0
Obj 5625.1701 Primal inf 2.2580657 (48)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">3
Obj 5623.2228 Primal inf 5.4953389 (94)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">…<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">40
Obj 5612.1607 Primal inf 1.3658683 (28)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Primal
infeasible - objective value 5612.1607<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">The
objective value (5625.1701) of the integer solution found by
the feasibility pump algorithm corresponds to the objective
value of the optimal solution.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">It
seems that CBC does some kind of postsolve which fixes
variables and that appears to be infeasible. Does CBC have a
parameter to switch off the postsolve?<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">I
can provide a LP or MPS file of the model. The scaling of
the model seems ok.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Best
regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier New"">Marcel
Hunting<o:p></o:p></span></p>
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