Lot Sizing Implementation

[brkylmz]

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 213 times

code.gms

(7.09 KiB) Downloaded 200 times

Best Regards,
Burak.

[Renger]

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

[brkylmz]

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.