Hi. Recently, i m working on converting mathematical model into OPL language for CPLEX. i managed to run the code but no solution computed. Hope someone can give me some guidance and advices. Thank you. Here are the code and the mathematical formulation. 

Mod.File: 

int v=...; //number of customers

range V=1..v; //customers - where 1 is the depot

int k=...;//number of vehicles

range K=1..k; //number of vehicles
float Distance [V][V] = ...;//Distance between customers and depot
float Capacity= ... ;//Capacity per vehicle
float Demand[V] = ...; //demand for each customer
dvar boolean x[V][V];// route driven between customer i and j
dvar float+ y[V];

//Objective Function
minimize
sum(i, j in V: i != j)
x[i][j]*Distance[i][j];

subject to {

//Constraints 1: Exactly one vehicle in
forall(j in V: j != 1)
sum (i in V)
x[i][j] == 1;

//Constraints 2: Exactly one vehicle out
forall(i in V: i != 1)
sum (j in V)
x[i][j] == 1;

//Constraints 1: Exactly one vehicle in

sum (j in V, k in K )
x[1][j] == k;


//Constraints 2:

// sum (i in V, k in K )
// // x[i][1] == k;

//Constraints 4: flow conservation or to ensure that the same vehicle in and out
forall( h in V:h!=1)
sum(i in V) x[i][h] - sum(j in V) x[h][j]== 0;

forall(i,j in V)
x[i][j] + x[j][i] <= 1;

forall(i ,j in V: i != 1) //i in V: i!= 1,j in V:j!= 1 && j!=i
y[j] >= y[i] + Demand[j]*x[i][j]- Capacity*(1-x[i][j]);

forall(j in V: j!= 1)
y[j] >= Demand[j] ;

forall(j in V: j!= 1)
y[j] <= Capacity;

}

Dat File: 

v=7; // number of customers
k=3 ; //number of vehicles

Distance= [
[ 0 15 10 30 15 35 22 ],
[ 15 0 24 23 20 36 12 ],
[ 10 24 0 36 11 37 13 ],
[ 30 23 36 0 42 38 23 ],
[ 15 20 11 42 0 39 14 ],
[ 35 36 37 38 39 0 15 ],
[ 22 12 13 23 14 15 0 ]
]; // Distance between customers and depot

Capacity = 120;// capacity of the vehicle
Demand = [0 30 50 40 30 50 40];// demand for each customer

------------------------------
Kien Hua Ting
------------------------------

#DecisionOptimization

If you use named constraints also known as constraint label, then the IDE will automatically launch a feasopt when the model is infeasible to determine which constraint is blocking.
Example:
```
//Constraints 1: Exactly one vehicle in
forall(j in V: j != 1)
c1: sum (i in V)
x[i][j] == 1;
//Constraints 2: Exactly one vehicle out
forall(i in V: i != 1)
c2: sum (j in V)
x[i][j] == 1;
```
If you label all the constraints of your model, then CPLEX detects some issues with customer number 3.


This debug feature will help you determine if you formulation is bad, if data is bad, or control what CPLEX can relax or not (by default, when OPL uses feasopt, it uses only named constraints).

A good pointer in the documentation is How relaxation and conflict search works

Ibm		remove preview
How relaxation and conflict search works Relaxations and conflicts both express the infeasibility of a model and propose steps towards feasibility. After you have had hands-on experience with the nurse scheduling example, learn how to differentiate between Relaxations and Conflicts. View this on Ibm >

------------------------------
Vincent Beraudier
------------------------------