[Scip] How to get all feasible solutions reached during the SCIP solve ?

[Stefan Heinz]

Dear Hélène,

Regarding the event SCIP_EVENTTYPE_SOLFOUND. You also could check our 
event handler example:

http://scip.zib.de/doc/examples/Eventhdlr/index.html

Besides that SCIP is also capable of counting/collecting all feasible 
solution. For that you call SCIPcount() instead of SCIPsolve():

http://scip.zib.de/doc/html/cons__countsols_8h.html#aef183d6883f1917bffb15159f7b856fd

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

Best Stefan

On 01/27/12 10:48, Gerald Gamrath wrote:
> Dear Hélène,
>
> you can call SCIPgetSols() which returns an array of feasible 
> solutions found so far and SCIPgetNSols() to get the number of 
> solution stored. By default, SCIP stores at most 100 solutions in this 
> storage, and stores only the 100 best solutions, if more than 100 are 
> found. You can change this by changing the parameter "limits/maxsol".
>
> However, whenever the event SCIP_EVENTTYPE_SOLFOUND is thrown, the 
> solution that causes this should be feasible. How do you check the 
> feasibility of the solution? It might happen, that constraints are 
> changed (e.g., scaled, shifted, etc.) in presolving, so you should 
> compare the solution values of the transformed variables to the 
> transformed constraints, if you get the original solution values, you 
> should check against the original constraints.
>
> Best,
> Gerald
>
> Am 27.01.2012 09:40, schrieb Hélène Toussaint:
>> Hi
>>
>> I'd like to get all the feasible solutions that SCIP have found 
>> during its solving process.
>>
>> I have tried to do it with a constraint handler using the event 
>> SCIP_EVENTTYPE_SOLFOUND. 
>> <http://scip.zib.de/doc/html/type__event_8h.html#ac4326687adf8b4175a2a2145b592401b>However 
>> when I enter the scip_exec function of this class the current 
>> solution often violate the constraints (I get the variable values 
>> with the SCIPgetSolVal function). Moreover I never enter this 
>> function when the optimal solution is found.
>>
>> Does it exist any method to get all the feasible solutions ?
>>
>> Best regards
>> Hélène
>>
>>
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>
>
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