Long computation time

  • 14 May 2019
  • 2 replies


I am performing an Vehicle Routing Problem with Time Windows in AIMMS.

The problem consists of 164 locations. I already expected that using all these locations would take a very long time. Therefore, I decided to divide this area into sub-areas.

I tested the model with 8 locations and for those locations I got a result. However, I am now doing the same for another area which consists of 18 locations and the computation time is very long. It stays at a gap of 38% and once in a while it decreases with 0,01%.

Now is my question is there something I can do about this as it seems that the model does work for smaller areas? If you need my model for this, please let me know to which address I can send it to as the data is confidential.

Kind regards,


2 replies

Userlevel 6
Badge +6
Hi Claire, thanks for your question.

This article has some efficiency tips that may help: https://how-to.aimms.com/Articles/125/125-execution-efficiency.html

@mohansx perhaps you can offer some further advice specific to this situation?
Userlevel 5
Badge +5
Hello @Claire ,

Did you use proper domain conditions on your variables and constraints so that the model is better equipped for scaling up in size ?

It would be helpful to take a look at your model before we can offer any proper advice. Can you send the project folder zipped along with the data case to support@aimms.com ?


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