Originally posted by: Sung_Hwang

Hello,

 

I am using CPLEX opl for an optimization.

 

I would like to ask a question which approach is better for CPLEX performance, 1) Nested for loop or 2) Separated for loop ?

 

For example, I am going to build the constraint set as below.

1) Nested for loop

forall (d in period, w in workers, t in training: d== tr.dayNumber){

   forall (d2 in period : d <= d2 <= d+8 && schedule[p][d2]=="V")

           X_[p][d] ==0;

 

  

 forall (d2 in period : d <= d2 <= d+8 && schedule[p][d2]=="L")

           X_[p][d] ==0;

}

 

or 

2)  Separated for loop

forall (d in period, w in workers, t in training: d== tr.dayNumber){

   forall (d2 in period : d <= d2 <= d+8 && schedule[p][d2]=="V")

           X_[p][d] ==0;

}

 

forall (d in period, w in workers, t in training: d== tr.dayNumber){ 

     forall (d2 in period : d <= d2 <= d+8 && schedule[p][d2]=="L")

            X_[p][d] ==0;

}

 

Thank you in advance for all your comments

 

#DecisionOptimization
#OPLusingCPLEXOptimizer

Hi,

I would go for nested.

Because it saves some computation at extraction time.

regards

#DecisionOptimization
#OPLusingCPLEXOptimizer