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<span>Hi Barry, </span>
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<div><span>Thank you for the bug report. We looked into the issue, and it appears to be a valid bug when using "<span>numerics/feastol = <span>1e-09"</span></span> that is resulting in an invalid node cutoff. </span></div>
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<div><span>It requires further investigation. We will reach out to you with a fix as soon as we have one.</span></div>
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<div><span>Best regards,</span></div>
<div><span>Gioni</span>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>Von:</b> Scip <scip-bounces@zib.de> im Auftrag von Barry Hurley <b.hurley@keelvar.com><br>
<b>Gesendet:</b> Montag, 24. April 2023 15:06:30<br>
<b>An:</b> scip@zib.de<br>
<b>Betreff:</b> [SCIP] Sub-optimal solution produced after upgrade to SCIP version 8.0.3</font>
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<div dir="auto">Hi, we were looking at upgrading from SCIP version 7 to version 8.0.3 but one of our unit-tests is catching a regression where SCIP appears to be producing a sub-optimal solution and claiming optimality. We are using SCIP via the LP file interface,
the files to reproduce are attached. problem.lp is the original problem, and problem-forced-solution.lp extends this with an additional constraint called `FORCED_SOLUTION` to force the optimal solution. Also including the parameter settings used.<br>
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The solution should have an optimal objective value of 115, but SCIP version 8.0.3 is incorrectly producing a solution with objective value 120, even with gap zero. The solution is valid, just sub-optimal. There is one difference in the assignment, binary variable
X_2__1_ has an objective coefficient of 15, but SCIP 8 is incorrectly assigning binary variable X_3__1_ to 1 instead even though its objective coefficient is higher at 20.<br>
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Would you have any advice if there is something we are using SCIP incorrectly, or if this is a legitimate bug? Other than the attached parameter settings, we are using the pre-built binaries on ubuntu x86. Many thanks in advance.</div>
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<div class="matchFont">Regards,<br>
Barry Hurley</div>
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