Originally posted by: medistif@hotmail.fr

Hello,

I have a model in cplex (concert technology, c++), i want to launch several resolutions, so i want to do it with a "for" loop  and in change a parameter in each iteration.

cplex.extract(model);
      
      if(cplex.solve()){
        
          env.out() << cplex.getStatus() << endl;
      
      for(int i = 0; i < k ; i++) {
          
         env.out() << "  " << cplex.getValue(var[i]) << "";
      }
      env.out() << endl;
      
      }

so what have i to put inside for start for example five resolution (all of this code ) ? 

thank you for your answers.

Do you want to solve the same model 5 times with different parameter settings or do you want to solve 5 different models?

In case you want to solve the same model with 5 different parameters settings it is as simple as

for (int round = 0; round < 5; ++round) {
   cplex.clearModel();
   cplex.extract(model);
   cplex.setParam(...); // Your parameter changes here.
   if ( cplex.solve() ) { ... }
}

Originally posted by: medistif@hotmail.fr

Yes i want to solve the same model 5 times with different parameter in each iteration. so i will try your example, i want just to know if i would like to change an parameter for example param1 = 0, i have to do it in this line: cplex.setParam(...); ? or can i juste make 

for (int round = 0; round < 5; ++round) {
   cplex.clearModel();
   cplex.extract(model);
   param1 = 0; //*********changing param1 ? **********//
   cplex.setParam(...); // Your parameter changes here.
   if ( cplex.solve() ) { ... }
}

You need to change parameters using cplex.setParam(...);

You probably also want to call cplex.setDefaults() at the beginning of the loop to reset all parameters to their default values (I forgot to mention that before).