Originally posted by: heidizh

I have a difficulty in expressing the subtour elimination constraint of the selective traveling salesman problem or the orienteering problem. Please help me, thanks very much !!

In the attachment is the constraint that I need to express using CPLEX. Looking forward to a prompt reply! Thanks !!

Best regards,

Heidi

#DecisionOptimization
#OPLusingCPLEXOptimizer

Hi,

 

suppose you want all the subsets of the set s in the array of sets s2

 

{string} s={"A","B","C","D"};

 

 

 {string} s2[i in 0..ftoi(pow(2,card(s)))-1]={};

 

int nb=ftoi(pow(2,card(s)));

 

execute

{

 for(var i in s)

 {

  

   for(var j=0;j<=nb-1;j++)

   {

     if ((j >> Opl.ord(s,i)) % 2==1) s2[j].add(i);

   }   

 }

 

 writeln(s2);  

}  

 

and then you can iterate in a constraint with

 

forall(k in 0..ftoi(pow(2,card(s)))-1)

 

and then use s2[k]

 

regards

#DecisionOptimization
#OPLusingCPLEXOptimizer

This answered

https://www.ibm.com/developerworks/community/forums/html/topic?id=4f9f3a1e-2933-47d1-9acb-5c632598f805&ps=25

#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: heidizh

Hi, Alex

Thank you very much. You are always there when I need help. 

Best regards,

Heidi

#DecisionOptimization
#OPLusingCPLEXOptimizer