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<span style="font-family: "Times New Roman", Times, serif; font-size: 12pt; color: rgb(0, 0, 0);">Dear SCIP team,</span>
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I'm currently working on integrating machine learning into presolve methods for MIPs, specifically focusing on Vehicle Routing Problems (VRPs). I am continuing the work of a previous student who started using SCIP. The initial goal is to use SCIP presolve,
gather some statistics for feature selection, and then call a heuristic for solving the MIP of a VRP. I have a bunch of .cip files of VRPs, and I need to read them, use presolve, extract the model after presolve (to get the coefficients from linear/quadratic
constraints/objective), solve the resulting MIP with the heuristic, and use SCIP's post-solve to get the solution.</div>
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Unfortunately, my colleague did not leave much documentation other than a Python code using PySCIPOpt for model creation and a note mentioning that we need SCIP's C++ wrapper to do the rest.</div>
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This is my first time using SCIP. I've spent a couple of days working with SCIP and have managed to use the C-API to read the .cip files, call the presolve, and retrieve some of the linear coefficients in the objectives/constraints. I'm currently using
<code>SCIPfindConshdlr</code> and <code>SCIPconsGetHdlr</code> to identify the linear and quadratic constraints, but I still don't know how to get the quadratic coefficients from the objective and constraints.</div>
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After this initial experience with SCIP, I would like to ask for your expertise in confirming whether what I am trying to do is feasible with the latest version of SCIP and the C-API, especially considering that I have problems with and without quadratic constraints
(and possibly quadratic objectives).</div>
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I would greatly appreciate any advice you can share to help me determine if my plan is possible and how to proceed with the project.</div>
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Thank you in advance for your support!</div>
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Best,</div>
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<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-family: Times, "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 0);"><b>David Escobar Vargas PhD</b></span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-family: Times, "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 0);"><b>Senior Algorithms Researcher</b></span></p>
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<span style="background-color: rgb(255, 255, 255);">Postdoctoral Fellow, Université Laval</span></div>
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Interuniversity Research Centre on Enterprise Networks, Logistics and Transportation (CIRRELT)</div>
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Montreal, Canada</div>
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