Originally posted by: Doulee

Hello,

I've been struggling with my model for a good week. Right now I either get Infeasibility row 'c2':  0  = 1 (with j in FentCEnd in the first constraint) or Row 'c38' infeasible, all entries at implied bounds. (with j in C0End in the first constraint). 

In my model I have 2 nodes to represent 1 charging station : an entry node and an exit node. I've been thinking about merging these two into just one charging station node. Either way, some arcs are infeasible in the model : either arcs that go from a customer to an exit charging node, or arcs that exceed the capacity/charge/time constraints without having to look at routing. I was thinking that getting rid of these arcs before running the model might help me solve the errors I get but I have no idea how I can do that in cplex. Would it be possible to do that in an execute INITIALIZE{} ? Or will doing this not solve anything and my model is just wrong at its core ?

Thanks a lot in advance !

Hi,

you could label your constraints and then you ll get some info about what has to be relaxed.

For instance

forall (i in C) ct1:sum(k in Vehicles, j in C0End:i!=j) x[i][j][k]==1; //all the customers are visited
    //forall (i in Fent) sum(k in Vehicles,j in Nend:i!=j) x[i][j][k]<=1; //you can or cannot visit a recharging station
     forall (k in Vehicles, j in N) ct2:sum(i in Nend:i!=j) x[j][i][k]-sum(i in N0:i!=j) x[i][j][k]==0;
    //forall (k in Vehicles,i in P) sum(j in N:i!=j) x[j][i][k]-sum(j in N:i!=j) x[j][n+i][k]==0;
    forall(k in Vehicles) ct3:sum(j in Pend) x[1][j][k]==1;
    forall(k in Vehicles) ct4: sum(j in D0) x[j][2*n+6][k]==1;

will give you some conflicts and relaxation

regards

Originally posted by: Doulee

Yes of course here's an updated version of the model/data.

I thought cplex named them automatically thanks for the hint !

Hi,

in OPL documentation you could read

IDE and OPL > CPLEX Studio IDE > IDE Tutorials

Relaxing infeasible models

Uses the nurses example to demonstrate how the IDE detects conflicts and searches for relaxations in OPL models that appear infeasible after execution.

regards