Cplex model, no Dvar values, in vehicle routing

Question

 int NStations1= ...;
 int Nstations2=...;

range Stations1= 1..NStations1;
range Stations2= 1..Nstations2;



 int demand1[Stations1]=...;
 int demand2[Stations2]=...;
int distance[Stations1][Stations2]=...;


int AvailTime=...;
int Capacity=...;


  dvar float+ x[Stations1][Stations2];
  dvar float+ f[Stations1][Stations2];

 minimize sum(i in Stations1) sum(j in Stations2) x[i][j]*distance[i][j];


 subject to 
  {

  forall (i in Stations1) sum(j in Stations2) (f[j][i]-f[i][j]) <= demand1[i];

  forall (i in Stations1) sum(j in Stations2) x[i][j] == 1 ;

 forall (i in Stations1)  sum(j in Stations2) x[j][i] == 1;


  forall (i in Stations1, j in Stations2)      
  {0<= f[i][j];
     f[i][j] <= x[i][j]*Capacity;}

Data: NStations1=4; Nstations2=4;

      demand1=[5 , 3, 4, 7];
       demand2=[5 , 3, 4, 7];
       distance=[ [ 9 2 7 4 ]
                    [ 2 5 3 3 ]
                       [ 8 4 13 8 ]
                       [ 7 3 4 3 ]
          
         ];
      AvailTime=3600;
      Capacity= 30;

Question:

I don't get values for my dvar, f while I got values for this parameter before adding the last constraint, but I need a capacity constraint ? How to solve this

Answer 1

I get

x = [[0
             0 0 1]
             [1 0 0 0]
             [0 1 0 0]
             [0 0 1 0]];
f = [[0 0 0 0]
             [0 0 0 0]
             [0 0 0 0]
             [0 0 0 0]];

if I run your model in the IDE with CPLEX 22.1

and if I turn your objective into

minimize staticLex(sum(i in Stations1) sum(j in Stations2) x[i][j]*distance[i][j],-sum(i in Stations1,j in Stations2) f[i][j]);

then I get

x = [[0
             0 0 1]
             [1 0 0 0]
             [0 1 0 0]
             [0 0 1 0]];
f = [[0 0 0 30]
             [30 0 0 0]
             [0 30 0 0]
             [0 0 30 0]];