RS01234: WITH INTENSITY SET TO 4, SOLUTION POOL MAY NOT PROPERLY ENUMERATE ALL FEASIBLE SOLUTIONS ON TRIVIAL MODELS

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APAR status

  • Closed as fixed if next.

Error description

  • Setting the solution pool intensity parameter to 4 instructs
    CPLEX to enumerate all feasible solutions.   However, if a
    model is simple enough that CPLEX can trivially derive a bound
    on the optimal objective value and a feasible solution with
    that value, optimality has been proved, and the solution pool
    algorithm doesn't generate the tree needed to enumerate all
    feasible solutions.
    
    For more information/discussion, see
    
    http://orinanobworld.blogspot.com/2013/01/solution-pool-all-is-n
    ot-all.html
    
    RTC-15222
    
    
    This only strikes on very simple models that solve to optimality
    before the main presolve loop starts.
    

Local fix

  • Set the heuristic frequency parameter to -1
    
    Also, do not set the solution pool absgap or mipgap parameters
    to finite values.
    

Problem summary

  • Solution pool may not properly enumerate all feasible solutions
    on trivial models
    

Problem conclusion

Temporary fix

  •  Disable heuristics.   Also, don't set
    
     solution pool absgap or mipgap parameters.
    

Comments

APAR Information

  • APAR number

    RS01234

  • Reported component name

    CPLEX OPTI STUD

  • Reported component ID

    5725A0600

  • Reported release

    C50

  • Status

    CLOSED FIN

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-02-07

  • Closed date

    2013-04-12

  • Last modified date

    2013-04-12

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels

  • RC50 PSY

       UP



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Document information


More support for:

IBM ILOG CPLEX Optimization Studio

Software version:

C50

Reference #:

RS01234

Modified date:

2013-04-12

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