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<div><span></span>Dear Jakob,</div><div><br></div><div>The barrier algorithm terminated very quickly and did not return dual bound. </div><div><br></div><div>Thanks,</div><div><br></div><div><br></div><div>Xiangyong</div>
<blockquote style="margin-top: 0px; margin-bottom: 0px; margin-left: 0.5em;"><div> </div><div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm"><div style="PADDING-RIGHT: 8px; PADDING-LEFT: 8px; FONT-SIZE: 12px;FONT-FAMILY:tahoma;COLOR:#000000; BACKGROUND: #efefef; PADDING-BOTTOM: 8px; PADDING-TOP: 8px"><div><b>From:</b> <a href="mailto:witzig@zib.de">Jakob Witzig</a></div><div><b>Date:</b> 2017-01-16 17:29</div><div><b>To:</b> <a href="mailto:lixiangyong@163.com">lixiangyong@163.com</a></div><div><b>Subject:</b> Re: [SCIP] How to change lp method in SCIP</div></div></div><div><div>Hi,</div>
<div> </div>
<div>are the LP values only slightly different, e.g., within tolerances or </div>
<div>completely different? Slightly different values are to expect when you </div>
<div>use different algorithms to solve the LP.</div>
<div> </div>
<div>Since you use Cplex as an LP solver, I cannot tell you anything about </div>
<div>the internal differences.</div>
<div> </div>
<div>Cheers,</div>
<div>Jakob</div>
<div> </div>
<div>Am 16.01.2017 um 09:17 schrieb lixiangyong@163.com:</div>
<div>></div>
<div>> Dear Jakob,</div>
<div>></div>
<div>> Thanks.</div>
<div>></div>
<div>> But when I respectively set lp/initalgorithm to primal and barrier, I</div>
<div>> got different LP values.</div>
<div>></div>
<div>> Best regards,</div>
<div>></div>
<div>></div>
<div>> Xiangyong</div>
<div>></div>
<div>></div>
<div>></div>
<div>></div>
<div>> *From:* Jakob Witzig <mailto:witzig@zib.de></div>
<div>> *Date:* 2017-01-16 15:55</div>
<div>> *To:* lixiangyong@163.com <mailto:lixiangyong@163.com></div>
<div>> *CC:* SCIP <mailto:scip@zib.de></div>
<div>> *Subject:* Re: [SCIP] How to change lp method in SCIP</div>
<div>> Hello Xiangyong,</div>
<div>></div>
<div>> a list of all parameters can be found here:</div>
<div>> http://scip.zib.de/doc/html/PARAMETERS.php</div>
<div>></div>
<div>> When you search for "lp" you will find the parameter lp/initalgorithm,</div>
<div>> the possible options are</div>
<div>> s : automatic simplex</div>
<div>> p : primal simplex</div>
<div>> d : dual simplex</div>
<div>> b : barrier</div>
<div>> c : barrier with crossover</div>
<div>></div>
<div>> Cheers,</div>
<div>> Jakob</div>
<div>></div>
<div>> Am 16.01.2017 um 08:25 schrieb lixiangyong@163.com:</div>
<div>> > Dear all,</div>
<div>> ></div>
<div>> > I am using SCIP to implement my own branch and price algorithm. CPLEX</div>
<div>> > is the lp solver.</div>
<div>> ></div>
<div>> > How can I change the method for solving the lp problem?</div>
<div>> ></div>
<div>> > Thanks,</div>
<div>> ></div>
<div>> ></div>
<div>> > Xiangyong</div>
<div>> ></div>
<div>> ></div>
<div>> ></div>
<div>> > _______________________________________________</div>
<div>> > Scip mailing list</div>
<div>> > Scip@zib.de</div>
<div>> > http://listserv.zib.de/mailman/listinfo/scip</div>
<div>> ></div>
<div>></div>
<div>></div>
<div>> --</div>
<div>> Jakob Witzig</div>
<div>></div>
<div>> Zuse Institute Berlin (ZIB)</div>
<div>></div>
<div>> Division Mathematical Optimization and Scientific Information</div>
<div>> Research Group Mathematical Optimization Methods</div>
<div>></div>
<div>> Takustrasse 7</div>
<div>> 14195 Berlin</div>
<div>></div>
<div>> Tel. : +49 (0)30 84185-416</div>
<div>> Fax : +49 (0)30 84185-269</div>
<div>> email: witzig@zib.de</div>
<div>></div>
<div> </div>
<div> </div>
<div>-- </div>
<div>Jakob Witzig</div>
<div> </div>
<div>Zuse Institute Berlin (ZIB)</div>
<div> </div>
<div>Division Mathematical Optimization and Scientific Information</div>
<div>Research Group Mathematical Optimization Methods</div>
<div> </div>
<div>Takustrasse 7</div>
<div>14195 Berlin</div>
<div> </div>
<div>Tel. : +49 (0)30 84185-416</div>
<div>Fax : +49 (0)30 84185-269</div>
<div>email: witzig@zib.de</div>
</div></blockquote>
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