Originally posted by: white_hat

Hi!

I have solved this MIP problem... (primary form)

then (because the dual form of this problem daesn't have dual variable) topic dual variable

I have solved so:

//change problem in FIXEDMILP
CPXchgprobtype(env, lp, CPXPROB_FIXEDMILP);
//optimaze... Is it useful??
CPXlpopt (env, lp);

        num_rows = CPXgetnumrows(env, lp);
        
        dual_varVals_P1.resize(num_rows);
        //get dual variable
        CPXgetpi (env, lp, &dual_varVals_P1[0], 0,num_rows - 1);
                
        //print  dual variables
        for (int i = 0; i < num_rows; i++) {
                cout << dual_varVals_P1[i] << endl;
        }
        
//RETURN TO THE ORIGINAL FORM OF PROBLEM
CPXchgprobtype (env, lp, CPXPROB_MILP);

Now.... (if this code is correct) I have solved this problem (dual form)

My second question is what is v0  dual variable? how can I get it?

First of all, why do you say your problem is a MIP? According to your picture it does not have integer variables?

If you solved the explicit dual then you can get the values of v0 using CPXgetx().

Originally posted by: white_hat

yes infact... I'm very stupid...This is a simple LP problem... thanks anyway for your answer!