<div dir="ltr">Hi all,<div><br></div><div>If I request the duals using the Cbc binary on a problem that ends up being infeasible (see attached model.lp file for a minimal example) I encounter a segfault:</div><div><br></div>





<p class="inbox-inbox-p1"><span class="inbox-inbox-s1">$ <font face="monospace">cbc</font></span><font face="monospace"><span class="inbox-inbox-s2"> -import </span><span class="inbox-inbox-s1">model.lp</span><span class="inbox-inbox-s2"> -solve -printingOptions all -solution </span><span class="inbox-inbox-s1">model.sol</span><span class="inbox-inbox-s2"> -printingOptions rhs<span class="inbox-inbox-Apple-converted-space">  </span>-solution </span><span class="inbox-inbox-s1">rhsranges.txt</span><span class="inbox-inbox-s2"> -printingOptions objective -solution costranges.txt<span class="inbox-inbox-Apple-converted-space"> </span></span></font></p>
<p class="inbox-inbox-p1"><span class="inbox-inbox-s2"><font face="monospace">Welcome to the CBC MILP Solver<span class="inbox-inbox-Apple-converted-space"> <br></span></font></span><span style="font-family:monospace;line-height:1.5">Version: 2.9.8</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5"> <br></span><span style="font-family:monospace;line-height:1.5">Build Date: Apr 28 2016</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5"> <br></span><span style="font-family:monospace;line-height:1.5">Revision Number: 2277</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5"> <br></span><span style="font-family:monospace;line-height:1.5"><br>command line - cbc -import model.lp -solve -printingOptions all -solution model.sol -printingOptions rhs -solution rhsranges.txt -printingOptions objective -solution costranges.txt (default strategy 1)<br></span><span style="font-family:monospace;line-height:1.5"><br>Presolve determined that the problem was infeasible with tolerance of 1e-08<br></span><span style="font-family:monospace;line-height:1.5"><br>Analysis indicates model infeasible or unbounded<br></span><span style="font-family:monospace;line-height:1.5">0</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">  </span><span style="font-family:monospace;line-height:1.5">Obj 0 Primal inf 1.9999999 (1) Dual inf 0.9999999 (1)<br></span><span style="font-family:monospace;line-height:1.5">1</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">  </span><span style="font-family:monospace;line-height:1.5">Obj 0 Primal inf 0.9999999 (1)<br></span><span style="font-family:monospace;line-height:1.5">Primal infeasible - objective value 0<br></span><span style="font-family:monospace;line-height:1.5">PrimalInfeasible objective 0 - 1 iterations time 0.002<br></span><span style="font-family:monospace;line-height:1.5"><br>Result - Linear relaxation infeasible<br></span><span style="font-family:monospace;line-height:1.5"><br>Enumerated nodes: </span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">          </span><span style="font-family:monospace;line-height:1.5">0<br></span><span style="font-family:monospace;line-height:1.5">Total iterations: </span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">          </span><span style="font-family:monospace;line-height:1.5">0<br></span><span style="font-family:monospace;line-height:1.5">Time (CPU seconds): </span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">        </span><span style="font-family:monospace;line-height:1.5">0.00<br></span><span style="font-family:monospace;line-height:1.5">Time (Wallclock Seconds): </span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">  </span><span style="font-family:monospace;line-height:1.5">0.01<br></span><span style="font-family:monospace;line-height:1.5"><br>Option for printingOptions changed from normal to all<br></span><span style="font-family:monospace;line-height:1.5">Option for printingOptions changed from all to rhs!ranging<br></span><span style="font-family:monospace;line-height:1.5">0</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">  </span><span style="font-family:monospace;line-height:1.5">Obj 0 Primal inf 0.9999999 (1)<br></span><span style="font-family:monospace;line-height:1.5">Primal infeasible - objective value 0<br></span><span style="font-family:monospace;line-height:1.5">Primal infeasible - objective value 0<br></span><span style="font-family:monospace;line-height:1.5">[1]</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5">    </span><span style="font-family:monospace;line-height:1.5">22862 segmentation fault</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5"> </span><span style="font-family:monospace;line-height:1.5">cbc -import model.lp -solve -printingOptions</span><span class="inbox-inbox-Apple-converted-space" style="font-family:monospace;line-height:1.5"> </span><span style="font-family:monospace;line-height:1.5"> </span></p><div><br></div><div>(I also posted this to the issue tracker: <a href="https://projects.coin-or.org/Cbc/ticket/170">https://projects.coin-or.org/Cbc/ticket/170</a>)</div></div>