[SCIP] SCIP multithreading solver DFiberSCIP to solve IP

[usa usa]

Also, I am checking
 https://scip.zib.de/doc-6.0.2/html/PARAMETERS.php

I would like to set up a mingap (e.g. 2%) so that the solver stops and
return a (sub)optimal solution for the given gap.

thanks


On Wed, Apr 29, 2020 at 2:28 AM Marc Pfetsch <
pfetsch at mathematik.tu-darmstadt.de> wrote:

>
>
> Hi David,
>
> let me add to Ambros' answer:
>
> If you run a problem in the command line and the problem turns out to be
> infeasible, you can do "change minuc". This will set up a problem that
> tries to minimize the number of unsatisfied constraints (i.e., it
> essentially does what Ambros explained below, but uses indicator
> constraints).
>
> From the output you can sometimes guess what the problem is (if the
> problem can be solved).
>
> Best
>
> Marc
>
> On 29/04/2020 10:21, Ambros Gleixner wrote:
> > Hi David,
> >
> > I am happy you are so excited about the SCIP Optimization Suite. Because
> > there are many people subscribed to this mailing list, can you please in
> > the future make sure to collect all relevant information first and
> > report them in one e-mail at a time.  Otherwise, we are not even sure,
> > which question is still relevant.
> >
> > Now, e.g., has the infeasibility problem already been resolved?  SCIP
> > currently has no powerful method to analyze infeasibilities.  However,
> > you could build your own slack model by either adding
> >
> > - a continuous slack variable to each of your suspicious constraints, or
> >
> > - convert them into a big-M constraint with an auxiliary binary
> > activation variable,
> >
> > and then minimize the sum of slacks or binaries.  The solution to such
> > an auxiliary MIP may give you good hints on modeling errors.
> >
> > FiberSCIP can currently not be used through the Java interface, but you
> > could use the SCIPwriteOrigProblem method to write a MPS file of your
> > Java model, and then solve it on the command line with FiberSCIP, see
> > the ug/README file in the SCIP Optimization Suite release.
> >
> > Best,
> > Ambros
> >
> >
> >
> > Am 29.04.20 um 08:36 schrieb usa usa:
> >> Hi,
> >>
> >> I am trying to solve an Integer programming model by running
> >> java scip from IntelliJ Idea (community 2019.2) on macbook pro.
> >>
> >> My java is 11.
> >> My scipoptsuite: 6.0.2.
> >> My jscip cheked out from https://github.com/SCIP-Interfaces/JSCIPOpt
> >>
> >> My integer programming model took long time to be solved by SCIP solver.
> >>
> >> Based on this
> >> https://scip.zib.de/workshop2014/parascip_libraries.pdf
> >>
> >> I would like to find how to use FiberSCIP to improve the performance.
> >>
> >> Could anyone help me with this or point out some docs that may be
> >> helpful?
> >>
> >> thanks
> >>
> >> David
> >>
> >>
> >>
> >> _______________________________________________
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> >>
> >
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