Decision Optimization

Decision Optimization

Delivers prescriptive analytics capabilities and decision intelligence to improve decision-making.


#Analytics
#DecisionOptimization
#DecisionOptimization
 View Only
  • 1.  stuck after finishing optimization

    Posted 01/03/15 11:12 PM

    Originally posted by: prashanw


    I ran the optimizer and get the outcome below. Since I see the  ""Total (root+branch&cut) =    5.02 sec. (1736.46 ticks)" I would assume that the optimization finished. But CPLEX is stuck after this point for a long time and does not progress.

    I have around 100812 variables. I also set the time limit to be 5 seconds. I just want to see CPLEX terminating after 5s. The optimizer seems to finish at 5s judging by the "Total (root+branch&cut) =    5.02 sec. (1736.46 ticks)" line. I am not sure why it's stuck after that (it doesn't terminate ). I am using the Python API and limiting the time by "my_prob.parameters.timelimit.set(5)". This also seems to work fine when the number of variables in the objective is low (i.e around 30-40) . When the number of variables are low cplex seems to progress without getting stuck  (finishes optimization and terminates). I am also not sure how to debug this mainly because of the fact that the symptom is CPLEX getting stuck,

    Additionally I am not concerned about getting the optimal solution and more concerned about getting some viable solution within a specified time.

     

    Root node processing (before b&c):
      Real time             =    5.02 sec. (1736.46 ticks)
    Parallel b&c, 4 threads:
      Real time             =    0.00 sec. (0.00 ticks)
      Sync time (average)   =    0.00 sec.
      Wait time (average)   =    0.00 sec.
                              ------------
    Total (root+branch&cut) =    5.02 sec. (1736.46 ticks)

    #CPLEXOptimizers
    #DecisionOptimization


  • 2.  Re: stuck after finishing optimization

    Posted 01/04/15 04:41 AM

    Originally posted by: prashanw


    I actually found the reason. Basically CPLEX was finishing on time but an outside function was taking time to complete. Thanks!


    #CPLEXOptimizers
    #DecisionOptimization