csvoptimizationruntimecplexibm-ilog-opl

Set limitation on gap tolerance and run time


I have two questions:

  1. In IBM ILOG CPLEX, I wrote an OPL project. Because the code works with large scale data, it takes a lot of time to solve. What is the code for limitation the gap tolerance of MIP Problem and limitation the time?

  2. I want to have a CSV file containing my desired results. For example, I want to have an objective function and runtime and the facility variable in a CSV file. I got all these results but I want them to be written in a CSV file too.


Solution

  • 1) Add the following code before the minimize statement in your .mod file.

    execute
    {
       cplex.tilim=30; // 20 s time limt
       cplex.epgap=0.01 // 1% gep
    }
    

    You can confirm that it is taken into account by examining the engine log. It should have something like this at the very beginning:

    CPXPARAM_TimeLimit                               30
    CPXPARAM_MIP_Tolerances_MIPGap                   0.01
    

    2) You may rely on IloOplOutputFile

    See example in https://www.ibm.com/developerworks/community/forums/html/topic?id=3fd44d41-210b-4b81-a005-819530d6377b&ps=25