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</o:shapelayout></xml><![endif]--></head><body lang=DE link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>Hello,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>I'm using SCIP 7.0.3 for branch&cut with problem specific cut generation (constraint handler adding rows). All separators are turned off by not including the plugins.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>I noticed that SCIP is spending a significant amount of time separating knapsack cardinality cuts at the root node within the linear constraint handler. Those cuts do not improve the dual bound for my problem.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>As far as I can see this is caused by cons_linear.c line 15872ff because in the root node the local bound equals the global bound and therefore <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><i><span lang=EN-US style='font-size:12.0pt;color:black'>SCIPisLE(scip, loclowerbound, maxbound);<o:p></o:p></span></i></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>return TRUE (with equality) no matter what value I set to "<i>constraints/linear/maxcardbounddist</i>".<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>There are a few other parameter controlling the separation of linear constraints, but I'm not sure what side effects it can have to disable separation of linear constraints e.g. by setting <o:p></o:p></span></p><pre><span lang=EN-US style='color:black'>constraints/linear/maxrounds = 0<o:p></o:p></span></pre><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'> All my linear constraints are initial=TRUE and removable=FALSE.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>As a workaround I can modify cons_linear.c but it will probably hurt for general MIP I'd like to solve with the same build...<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;color:black'>Is there a clean way to disable knapsack cardinality cuts by setting parameters?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>With best regards,<br>Tobias Stengel<br><br>Siemens Digital Logistics GmbH<br>SL SDL TEC R&D SCS<br>Stumpfstr. 1<br>76131 Karlsruhe, Germany <br><a href="mailto:tobias.stengel@siemens-logistics.com"><span style='color:blue'>mailto:tobias.stengel@siemens-logistics.com</span></a><br><a href="http://www.siemens-digital-logistics.com"><span style='color:blue'>www.siemens-digital-logistics.com</span></a><br><br></span><span style='font-size:8.0pt;font-family:"Arial",sans-serif'>Management: Christopher Christian, Christian Schmidt<br>Registered office: Nachtweideweg 1-7, 67227 Frankenthal, Germany<br>Register Court: Ludwigshafen am Rhein, HRB 64386</span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>