Gurobi exceeded the time limit in clean environment

Awaiting user input

Eman Almoaili

March 21, 2025 12:23 Edited

• 
• 

Hi

I used a loop in main to loop over each instance in my dataset and I used an environment so the runtime does not overlap between each iteration of the loop (to ensure clean start for each iteration). Also, I set a timelimit (600 s), however, for some instances the runtime far exceeded 600, what can cause this behavior? I googled it but I cannoot find accuarte answer.
This is a sample of my code:

in main file:

for each instance n: 1 to 20
      call function VRPF(instance n).

in VRP file:

function VRPF:

    env = gp.Env(empty=True)
    env.setParam("TimeLimit", 600)  
    env.start()
    model = gp.Model(env=env, name="MIP-VRP")
    #set obj and constraints
     ...............
     model.optimize()
     runTime = model.Runtime
     # Clean up model and environment
     model.dispose()
     env.dispose()
     return solution, runTime

Also, I noticed that if I run those instances (that exceeded 600s) alone without being in a loop, they do not exceed 600, why?
Regards,

0

• 

  David Torres Sanchez

  • Gurobi Staff

  March 21, 2025 13:14

  Hi Eman,

  How much is the time limit exceeded? If it is a lot, can you provide some code for us to run?

  Cheers, 
  David

  0
• 

  Eman Almoaili

  March 21, 2025 14:48

  • 
  • 

  one instance is 1443 s

  the other one is 2537 s

  is that a lot?

  0
• 

  David Torres Sanchez

  • Gurobi Staff

  March 21, 2025 15:03

  That is a lot indeed! Please provide a way for us to reproduce this. Does it happen when you run the MPS file? Or only in your code?

  Cheers, 
  David

  0

Please sign in to leave a comment.