Originally posted by: Guerlain

Hello
I formulate a problem of inventory management, my objective is to serve in the first period the customers from the supplier and the second period, a balance of stock between customers can be made to minimize the cost of inventory and then, in the third period, the supplier delegates the stock to customers.
The main objective is to minimize inventory costs between supplier and customer.
I wrote the script but I have a problem with the booleen variable that allows customers to be served at each period.

Bellow the script 

Originally posted by: EdKlotz

Please provide more precise info regarding the problem.   What is the unexpected behavior you get, and which statements in the .mod file you attached do you think are involved in the problem?  

Originally posted by: Guerlain

Hello
the transfer variable is according to Appro, Picked and Transship (ie in the first and third periods the transfer of the stock will be done according to aprro and the second period according to transship and picked as a pick up and delievery problem)
but transf does not take into consideration in the result transship and picked.

Originally posted by: EdKlotz

I see the constraints

// Transfer constraints

forall(i in 2..n, k in Vehicles)
(y[i][k][1]==1) =>
(sum(k in Vehicles)Transf[i][k][1]<=sum(k in Vehicles, t in 1..2)Demand[i][k][t]);

forall(i in 2..n, k in Vehicles)
(y[i][k][2]==1) =>
(sum(k in Vehicles)Transf[i][k][2]<=Transship[i][2]+Picked[i][t]);

forall(i in 2..n, k in Vehicles)
(y[i][k][3]==1) =>
(sum(k in Vehicles)Transf[i][k][3]<=sum(k in Vehicles)Demand[i][k][3]);

forall(i in 2..n, t in 1..t, k in Vehicles)
(y[i][k][t]==0) =>
(Transf[i][k][t]==0);

So what do you mean when say "transf does not take into consideration in the result transship and picked."?   Do you mean that in

forall(i in 2..n, k in Vehicles)
(y[i][k][2]==1) =>
(sum(k in Vehicles)Transf[i][k][2]<=Transship[i][2]+Picked[i][t]);

there is an i and k such that y[k][k][2] = 1, but the constraint implied by that ((sum(k in Vehicles)Transf[i][k][2]<=Transship[i][2]+Picked[i][t]);) does not hold?

Originally posted by: Guerlain

So I have to add in the constraints the booleen variable y[i][k][2] ? 

Originally posted by: EdKlotz

I don't understand your question.   In terms of other constraints involving y[i][k][2], I see

// OU Constraints (inclure le transshipment)

forall(i in 2..n, k in Vehicles, t in 1..t)
sum(k in Vehicles)Appro[i][k][t]+Transship[i][t]-Picked[i][t] >= Born_Sup[i]*sum(k in Vehicles)y[i][k][t]-stock[i][t-1];

forall(i in 2..n, t in 1..t,k in Vehicles)
Appro[i][k][t]+Transship[i][t]-Picked[i][t]<=Born_Sup[i]*y[i][k][t];

Now, for t = 2, you also have

forall(i in 2..n, k in Vehicles)
Appro[i][k][2]==0;

So, it seems to me that the only way a particular y[i][k][2] gets forced to 1 is if Transship[i][2]-Picked[i][2] > 0.

But, for all other time periods, it certainly looks possible for y[i][k][t] to get forced to 1.

I'm still not clear on exactly what the unexpected result is.