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Best LP Bound on different systems


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Hi,

how is it possible to obtain a worse outcome on a more powerful PC system? Are there solver options which are benefitial for a faster PC system?

In my specific case, I run a Mathematical Program (MIP) minimizing a target function. Since the computation effort is quite high, I introduce an Upper Bound to reduce the solution set. However, if I run the identical probelm instance on two systems, the more powerful one is not able to even calculate a Lower Bound. I use CPLEX 20.1. Any idea why this could be or how to configure solver options?

 

Thanks and best regards

 

Best answer by Marcel Hunting

Hi @inkognitro. It would be a good idea to print the CPLEX status file for both runs. It will be printed in the log folder if you set the following options:

  • Solvers General option 'Solver listing messages' to 'All';
  • CPLEX option 'MIP display' to 'Nth node + info on node cuts';

Comparing the CPLEX status files might provide some useful information. I invite you to share them here.

 

How did you introduce an upper bound? By providing a MIP start?

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2 replies

Marcel Hunting
AIMMSian
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Hi @inkognitro. It would be a good idea to print the CPLEX status file for both runs. It will be printed in the log folder if you set the following options:

  • Solvers General option 'Solver listing messages' to 'All';
  • CPLEX option 'MIP display' to 'Nth node + info on node cuts';

Comparing the CPLEX status files might provide some useful information. I invite you to share them here.

 

How did you introduce an upper bound? By providing a MIP start?


Andrew
  • Former AIMMSian
  • 50 replies
  • April 7, 2021

Hi @inkognitro 

Did Marcel’s answer help you with your issue?