First, let me introduce myself (as its my first post):
Im and Industrial Engineer student making my end of master project studying the scheduling of a production plant. My tutor recommended me AIMMS to solve the MIP scheduling problem and, as you might have guessed none of us used this tool ever
So far so good, i have found a scientific paper that solves my particular problem ( i dont think i can upload the paper, so I’ll upload only the good stuff)
![](https://uploads-eu-west-1.insided.com/aimms-en/attachment/3be64aa1-7f19-4975-9f4f-3824d2c65a37.png)
![](https://uploads-eu-west-1.insided.com/aimms-en/attachment/40239929-ef99-4ea2-901a-9c1429118570.png)
![](https://uploads-eu-west-1.insided.com/aimms-en/attachment/407c849c-d1f0-4c87-9862-cfe6683e9af9.png)
If AIMMS has a good thing its that it was easy (even for me) to introduce most of the constraints and definitions. So i made (most) of them
But theres one that particularly bothers me, restriction (2) and in a lesser way (7). This ones check the inventory stock at the the end of a certain T time, but if T=0, then it check It-1 (which it doesnt exist). And if T=1, it check It=0
The thing is that I created a Parameter that holds the Initial Inventory and i wanted to keep as close as the formulation previously showed, so i went ahead and made some “adjustments” that worked in my head, but didnt work in reality.
![](https://uploads-eu-west-1.insided.com/aimms-en/attachment/e458ab6b-70cc-4149-b6c3-50ff25a54677.png)
I havent used AIMMS, but i have some minor experience in coding, so you will probably see where I am going with that: If t-1>0, you check the constraint on Inventario_Final (Final Inventory on English) otherwise, you check over the parameter Inventario_Inicial (Starting Inventory).
But I have a nasty error that i cant solve. Maybe you experts could help me😉
Thx in advance
PD: as a bonus, here you have the files (in Spanish, that is, sry)
Best answer by Marcel Hunting
View original