[SCIP] SCIP multithreading solver DFiberSCIP to solve IP

[Marc Pfetsch]

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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>