Lot Sizing Implementation

Problems with modeling
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brkylmz
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Lot Sizing Implementation

Post by brkylmz » 1 week ago

Hello Everyone,

I am trying to implement a lot sizing and scheduling model to GAMS.I am not getting any syntax errors but the model is not functioning properly.The model is not producing a valid production schedule.I am not sure what is causing the problem.I suspect that the Eq4 which is the inventory balance constraint is not working properly.

Here is the model and the gams code I wrote.Thanks for all your replies in advance!
Model.pdf
(162.57 KiB) Downloaded 14 times
code.gms
(7.09 KiB) Downloaded 12 times
Best Regards,
Burak.

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Renger
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Re: Lot Sizing Implementation

Post by Renger » 1 week ago

Hi Burak

I had a quick look at your model and the pdf file. Why are you restraining some of your equations to j > 1. The model description doesn't have these constraints (I believe).

Cheers
Renger
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brkylmz
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Re: Lot Sizing Implementation

Post by brkylmz » 1 week ago

Renger wrote:
1 week ago
Hi Burak

I had a quick look at your model and the pdf file. Why are you restraining some of your equations to j > 1. The model description doesn't have these constraints (I believe).

Cheers
Renger
Hi Renger,

The model assumes the jobs are j=1,2,....,J and j=0 is the neutral state.I defined j as J0*J6 so I am putting the constraint ord(j)>1 in the constraints that dont compute for j=0.

Cheers,
Burak.

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