[SCIP] How to change lp method in SCIP

[lixiangyong at 163.com]

Dear Jakob,

The barrier algorithm terminated very quickly and did not return dual bound. 

Thanks,


Xiangyong
 
From: Jakob Witzig
Date: 2017-01-16 17:29
To: lixiangyong at 163.com
Subject: Re: [SCIP] How to change lp method in SCIP
Hi,
 
are the LP values only slightly different, e.g., within tolerances or 
completely different? Slightly different values are to expect when you 
use different algorithms to solve the LP.
 
Since you use Cplex as an LP solver, I cannot tell you anything about 
the internal differences.
 
Cheers,
Jakob
 
Am 16.01.2017 um 09:17 schrieb lixiangyong at 163.com:
>
> Dear Jakob,
>
> Thanks.
>
> But when I respectively set  lp/initalgorithm to primal and barrier,  I
> got different LP values.
>
> Best regards,
>
>
> Xiangyong
>
>
>
>
>     *From:* Jakob Witzig <mailto:witzig at zib.de>
>     *Date:* 2017-01-16 15:55
>     *To:* lixiangyong at 163.com <mailto:lixiangyong at 163.com>
>     *CC:* SCIP <mailto:scip at zib.de>
>     *Subject:* Re: [SCIP] How to change lp method in SCIP
>     Hello Xiangyong,
>
>     a list of all parameters can be found here:
>     http://scip.zib.de/doc/html/PARAMETERS.php
>
>     When you search for "lp" you will find the parameter lp/initalgorithm,
>     the possible options are
>       s : automatic simplex
>       p : primal simplex
>       d : dual simplex
>       b : barrier
>       c : barrier with crossover
>
>     Cheers,
>     Jakob
>
>     Am 16.01.2017 um 08:25 schrieb lixiangyong at 163.com:
>     > Dear all,
>     >
>     > I am using SCIP to implement my own branch and price algorithm.  CPLEX
>     > is the lp solver.
>     >
>     > How can I change the method for solving the lp problem?
>     >
>     > Thanks,
>     >
>     >
>     > Xiangyong
>     >
>     >
>     >
>     > _______________________________________________
>     > Scip mailing list
>     > Scip at zib.de
>     > http://listserv.zib.de/mailman/listinfo/scip
>     >
>
>
>     --
>     Jakob Witzig
>
>     Zuse Institute Berlin (ZIB)
>
>     Division Mathematical Optimization and Scientific Information
>     Research Group Mathematical Optimization Methods
>
>     Takustrasse 7
>     14195 Berlin
>
>     Tel. : +49 (0)30 84185-416
>     Fax  : +49 (0)30 84185-269
>     email: witzig at zib.de
>
 
 
-- 
Jakob Witzig
 
Zuse Institute Berlin (ZIB)
 
Division Mathematical Optimization and Scientific Information
Research Group Mathematical Optimization Methods
 
Takustrasse 7
14195 Berlin
 
Tel. : +49 (0)30 84185-416
Fax  : +49 (0)30 84185-269
email: witzig at zib.de
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