Originally posted by: ShivaliLomate

Hi ,

I am running same mathematical problem in CPLEX 12.8 on two different laptop which have different processor. With exact same formulation, data set in one machine with less processor i got total objective of 72901378.702075 ( in engine log it says using 4 threads). and in other machine which have higher processor i got total objective of 72903901.2828 ( in engine log it says using 8 threads).In both cases total MIP gap is 0.00%. With use of more processor do i get better objective ? will you please tell me what is reason of different objective and how should i get same objective in both machine?

Of course the optimal objective value should not depend on the number of threads.

Is the MIP gap reported in the log 0.00% or did you set CPX_PARAM_EPGAP to 0? What is the solution status in both cases? Unless you set CPX_PARAM_EPGAP to 0, the gap may be so small that it shows as 0.00% in the log but is still larger than zero. Make sure that the solution status is CPXMIP_OPTIMAL (101) (or Optimal in the object oriented APIs, respectively) in both cases before comparing things.