[Scip] Setting Branching Priority with .set file

[Yuji Shinano]

Hi lotu1,

On 2015/03/30 19:27, lotu1 at gmx.de wrote:
> Thanks, that's what I'm doing currently. I just ran into some blocking issues when trying to pass
> alot of these variable settings through the command line. This might however have been caused by
> passing in the settings trough a java programme. I'll try the option with using an external file for
> these command, as you suggested.
> However, I'm also interested in using these branching pririties for fscip. But I guess that won't be
> possible.

It would be possible. You can specify all parameter settings for SCIP to fscip by using -sr and -s 
options.

     "fscip fscip_param_file problem_file_name [-l <logfile>] [-q] [-sl <settings>] [-s <settings>] 
[-sr <root_settings>]
      [-w <prefix_warm>] [-sth <number>] [-fsol <solution_file>] [-isol <initial solution file]"
        -l <logfile>           : copy SCIP output into log file
        -q                     : suppress SCIP screen messages
        -sl <settings>         : load parameter settings (.set) file for LoadCoordinator presolving
        -sr <root_settings>    : load parameter settings (.set) file for root node subtree solving
        -s <settings>          : load parameter settings (.set) file for additional node solving
        -w <prefix_warm>       : warm start file prefix ( prefix_warm_nodes.gz and 
prefix_warm_solution.txt are read )
        -sth <number>          : the number of solver threads used
        -fsol <solution file> : specify output solution file
        -isol <intial solution file> : specify initial solution file

One thing you have to do is to specify nopresolve_in_lc.set which is a fscip_param_file
to prohibit presolving in LoadCorrdinaotr and is provided in setting directory.

However, whether if it works well or not depending on how presolveing works on your instances
and how much effect you can expect from your settings.

Best,
Yuji


> *Gesendet:* Montag, 30. März 2015 um 11:48 Uhr
> *Von:* "Jakob Witzig" <witzig at zib.de>
> *An:* lotu1 at gmx.de
> *Cc:* scip at zib.de
> *Betreff:* Re: [Scip] Setting Branching Priority with .set file
> Hi lotu1,
>
> my first answer was not complete in probably to general. First, set the
> priority of variables through a *.set file is not possible but you can
> change the priority by using the interactive shell after loading your
> problem.
>
> A workaround would be using a "command file", e.g., myCommands.txt.
> Therefore, you use a file with some content like this:
>
> read myFile
> set branching priority myVar1 prio1
> set branching priority myVar2 prio2
> optimize
> quit
>
> and you execute SCIP with the command "scip < myCommands.txt"
>
> Best,
> Jakob
>
> On 03/30/15 11:01, Jakob Witzig wrote:
>  > Hi lotu1.
>  >
>  > No, it is not possible to specify branching priorities for variables. If
>  > you want to do this, you have to write your own branching rule, see:
>  > http://scip.zib.de/doc/html/BRANCH.php.
>  >
>  > Best,
>  > Jakob
>  >
>  > On 03/30/15 10:13, lotu1 at gmx.de wrote:
>  >> is it possible to set branching priorities (set/branching/priority) on
>  >> variables through a settings file? What is the syntax for this? E.g.
>  >> this does not work: set/branching/priority/myVar = 5
>  >> Thanks
>  >>
>  >>
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>
>
> --
> Jakob Witzig
>
> Konrad-Zuse-Zentrum für
> Informationstechnik Berlin (ZIB)
>
> Division Mathematical Optimization and Scientific Information
> Research Group Mathematical Optimization Methods
>
> Takustrasse 7
> 14195 Berlin
>
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>
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