[Scip] User constraints checking

[Abdelkader Ouali]

Dear Gerald,
In order to clarify my situation, I made a quick example containing a user constraint handler which stays always infeasible, I set both scip_check and scip_enfolp to return SCIP_INFEASIBLE.
When checking scip logs during solving process, i found a message claims infeasibility :feasible solution found by trivial heuristic after 0.0 seconds, objective value -3.000000e+00presolving:propagator <pseudoobj> detected infeasibility  
but after that, I get :SCIP Status        : problem is solved [optimal solution found]Solving Time (sec) : 0.00Solving Nodes      : 0Primal Bound       : -3.00000000000000e+00 (1 solutions)Dual Bound         : -3.00000000000000e+00Gap                : 0.00 %
SCIP should print [infeasible] rather then [optimal solution found]Please find the source code and the file containing SCIP logs for the example in the attachment.
Best regards---A. Ouali

Date: Mon, 10 Aug 2015 18:55:41 +0200
From: gamrath at zib.de
To: oualiaek at hotmail.fr; scip at zib.de
Subject: Re: [Scip] User constraints checking


  
    
  
  
    Dear Abdelkader,

      

      can you send some more information and perhaps the output of SCIP?
      I cannot imagine that SCIP states that the problem is infeasible
      but prints a solution afterwards.

      

      The scip_check method is mainly used to check feasibility of
      solutions generated by heuristics. Checking whether the node LP
      solution is feasible is done by the scip_enfolp method, which
      should normally do something to enforce feasibility, e.g., add a
      constraint or perform branching, but can also just return
      infeasible. If you did not modify this method to always return
      infeasible, it might happen that LP solutions are accepted to be
      feasible.

      

      Best,

      Gerald

      

      On 10.08.2015 14:30, Abdelkader Ouali wrote:

    
    
      
      Dear SCIP
          users,
        

        
        
          I am implementing my own constraints using the constraint
            handler as explained in the TSP example of SCIP,
          The problem I am facing is the feasibility checking with
            my own constraints, which they don't include problem
            variables in their scope, but use them to check the
            feasibility of other given information, 
          In order to see if SCIP respond to my constraints, I set
            the callback function scip_check returns always infeasible.
            In solving stage, SCIP detects the infeasibility, but after
            that it prints solutions that ignore my constraints.
        
        

        
        I want to know what is going on inside SCIP ! it detects
          infeasibility but rather prints infeasible solutions.
        

        
        Thanks in advance for any explanations.
        ---
        A. Ouali
      
      

      
      

      _______________________________________________
Scip mailing list
Scip at zib.de
http://listserv.zib.de/mailman/listinfo/scip

    
    
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.zib.de/pipermail/scip/attachments/20150810/7c1c7214/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: example.tar.gz
Type: application/x-gzip
Size: 4799 bytes
Desc: not available
URL: <http://listserv.zib.de/pipermail/scip/attachments/20150810/7c1c7214/attachment.bin>