how to make 2d array of strings in Cplex
//indics
{string} cluster=...;
setof(string) darkstore =...;
setof(string)demandpoint =...;
//data
cluster={chav,sree};
demandpoint=[{tsnami,adholokam,neelambari,ashrayam},{tg,pd,cp,dt}];
darkstore=[{dilucia,quickstart,babystores,yonnesbakery},{a,b,c,d}];