[Scip] Collecting feasible solutions in SCIP

Stefan Heinz heinz at zib.de
Wed May 30 07:53:00 MEST 2012


On 05/29/2012 10:24 PM, michael.winkler at zib.de wrote:
>> Is it possible in SCIP to collect specified number of solutions with less
>> than a specified MIP gap. ( For example,
>> I want to collect 2000 feasible solutions with less than 30% MIP gap).
>>
> You can add a constraint to restrict your feasible region to only count
> solution with less than 30% MIP gap. Note, that the gap can change due to
> new primal solutions or to a better dual bound. So the question should be
> to what value you want to define 30% and as a result use this to restrict
> your feasible region.
>
> Best, Micha
You can use the same trick as for counting optimal solutions see (all 
the way at the end of the page)

http://scip.zib.de/doc/html/COUNTER.html

First you solve your problem to optimality, then you add a constraint 
which forbids solution which a worse than 30% and start counting the 
number of feasible solutions.

Best Stefan


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