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  • Latest Post - ‏2013-01-21T07:12:17Z by SystemAdmin
SystemAdmin
SystemAdmin
7929 Posts

Pinned topic On optimality gap in CPLEX 12.1 and...

‏2013-01-20T18:41:50Z |
My first two questions are referring to optimality gap in CPLEX 12.1:

1. What is the code to display the optimality gap of an MIP if I use VB.NET for coding?

2. On the screen output, the best feasible integer solution returned within the time limit is 56. The "gap" is 100%. So what would be the lower bound to the optimal MIP solution?

My last question is: As I am using VB.NET with CPLEX 12.1, what is the latest version of CPLEX if I still prefer to VB.NET instead of switching to C++?

Thanks.

LIN
Updated on 2013-01-21T07:12:17Z at 2013-01-21T07:12:17Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
    7929 Posts

    Re: On optimality gap in CPLEX 12.1 and...

    ‏2013-01-21T07:12:17Z  
    > X4F5_KA_YUK_CARRIE_LIN wrote:
    > My first two questions are referring to optimality gap in CPLEX 12.1:
    >
    > 1. What is the code to display the optimality gap of an MIP if I use VB.NET for coding?
    >
    I did not check 12.1 as this is quite old but in recent versions there is the MIPRelativeGap property of the Cplex class. Can you please check if that does the trick for you.

    > 2. On the screen output, the best feasible integer solution returned within the time limit is 56. The "gap" is 100%. So what would be the lower bound to the optimal MIP solution?
    >
    A gap of 100% can mean two different things:
    1. The dual bound is 0.
    2. The relative MIP gap is 100%.
    To find the dual bound use property BestObjValue of the Cplex class.

    > My last question is: As I am using VB.NET with CPLEX 12.1, what is the latest version of CPLEX if I still prefer to VB.NET instead of switching to C++?
    >
    All versions newer than 12.1 should support VB.NET in the same way as 12.1. The newest version of CPLEX is 12.5.