Problem on Solving Constraints Mapping

  • 20 December 2022
  • 3 replies
  • 36 views

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Good day all,

I am one of the AIMMS beginners and would like to seek help upon my modelling project that I working on currently.

The project is about “Production Planning Optimisation for a High Tech Company” where the company is producing 5 assemblies using 22 materials in the period of 30 weeks.

The problem that I am facing while solving this model using AIMMS are as per below:

  1. Unable to solve the constraints 6 where at t=0, the onhand inventory must be equal to the input materials during the first week of assemble. The result shows infeasible solution as per below pictures.

 

 

I had attached the information of this project for better context. Note that, the similar question/model, can be solve by using python without having any error. And I had attached the reference link below for your reference and comparison.

 

May I know the things that I should double check when running this model ?

Appreciate that I can get the respond from you. Thank you.

 

Regards,

waisheng

 

 

reference link: https://medium.com/mlearning-ai/production-planning-optimisation-at-a-high-tech-manufacturing-firm-116c78f09742


3 replies

Userlevel 4
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@waisheng

If that's the constraint that is giving you trouble I would make certain that you carefully exclude t = 0 in the inventory balance constraint, or you will end up with two incompatible constraints for the inventory at t = 0.

Also, if you base your model off the formulation in the referenced article, then notice that the formulated constraint about the bottleneck rate does not match its textual description. In the formulated constraint all production in a period must be equal to the bottleneck rate, while the article mentions that is should be max the bottleneck rate. The charts in the article match the textual description. 

 

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@MarcelRoelofs Thank you for your kind response...Meaning I should change my constraint to be <= instead of = to fulfil the statement of max bottleneck rate...am i correct ?

Userlevel 4
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@waisheng 

Check.

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