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6 replies Latest Post - ‏2012-12-13T19:44:46Z by SystemAdmin
SystemAdmin
SystemAdmin
7929 Posts
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Pinned topic How to enumerate all IIS in infeasibale CSP

‏2012-12-11T19:13:55Z |
I have another question, the question is:
From a system constraints infeasible and by using Cplex, we can calculate
the Min IIS by using the ConflictRefiner.
I work in my doctoral thesis on the diagnostic of systems infeasible and i
need to calculate all IIS system using Cplex and MIN IIS COVER (MIN FS). I
know that there are heuristics to enumerate all of the IIS and then find
the MIN IIS COVER (the minimal set of constraints that covers all IIS
"NP-Hard Problem").
thanks
Updated on 2012-12-13T19:44:46Z at 2012-12-13T19:44:46Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
    7929 Posts
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    Re: How to enumerate all IIS in infeasibale CSP

    ‏2012-12-13T08:51:25Z  in response to SystemAdmin
    Hi
    I need a function in CPLEX allows to list all the IISS in a linear CSP feasible, I'm sure this question is easy for one of you
    Thank you
    • SystemAdmin
      SystemAdmin
      7929 Posts
      ACCEPTED ANSWER

      Re: How to enumerate all IIS in infeasibale CSP

      ‏2012-12-13T08:52:36Z  in response to SystemAdmin
      • CSP infeasible
    • SystemAdmin
      SystemAdmin
      7929 Posts
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      Re: How to enumerate all IIS in infeasibale CSP

      ‏2012-12-13T15:36:29Z  in response to SystemAdmin
      There is no function in CPLEX that enumerates all IISs.
      You could try to use the conflict refiner with different preferences to drive it to find different IISs.
      • SystemAdmin
        SystemAdmin
        7929 Posts
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        Re: How to enumerate all IIS in infeasibale CSP

        ‏2012-12-13T19:44:46Z  in response to SystemAdmin
        Thank you sir for your reply and your help.
        I have two other questions:
        1) Do not use preferences means that all the constraints are the same preference (different from (Hard constraint) and and from -1 (not considering the constraint))?
        2) you just tell me that I am sure that the output of Conflict Refiner is irreducible (A property of IIS) if don't use preferences, and you say in your second response that i can use the conflict refiner with different preferences to drive it to find different IISs.
        Thank you.
  • SystemAdmin
    SystemAdmin
    7929 Posts
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    Re: How to enumerate all IIS in infeasibale CSP

    ‏2012-12-13T14:47:00Z  in response to SystemAdmin
    I made a error, the output of this Conflict refiner does not necessarily IIS. In other words, there is not nécéssaiment the property of the irreducibility in the set incosistant on constraints returned by Conflcit Refiner "Black Box CPLEX (we have that informal descripitons for this function)"
    Thank you
    • SystemAdmin
      SystemAdmin
      7929 Posts
      ACCEPTED ANSWER

      Re: How to enumerate all IIS in infeasibale CSP

      ‏2012-12-13T15:35:30Z  in response to SystemAdmin
      If you don't use preferences or constraint grouping for the conflict refiner then the output of the conflict refiner will be irreducible.