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Using empty IloNumVar handle

  • 1.  Using empty IloNumVar handle

    Posted Wed September 18, 2013 03:10 AM
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    Originally posted by: Charles.Yu.Wang


    Dear Folks, 

    I meet this problem " Using empty IloNumVar handle" and cannot solve it. Basically, I think it is because I call something which is not declared, however, I cannot understand it. The following is my code.

     

     

    IloModel patternGenModel(env);
    IloObjective ReducedCost = IloAdd(patternGenModel, IloMinimize(env, 1));
    IloRangeArray halfDuplexConstraints(env);
    IloRangeArray coexistConstraints(env);
    IloNumVarArray activeLink(env, nodeNumber*nodeNumber, 0.0, 1.0, ILOINT);
     
    // (24) sum(v_ij) + sum(v_ji) <= 1: half-duplex constraint, whether a node is concurrently engaged in two active links
    for (i=0;i<nodeNumber;i++)
    {
    IloExpr duplexExpr(env);//for each of the i, there will be an expression, thus a new expression should be created.
    for (j=0;j<nodeNumber;j++)
    {
    if(i==j) 
    {

     

    cout << " step 1 " << activeLink.getSize() <<endl;
    activeLink[nodeNumber*i+j]=0;

     

    continue;
    }
    duplexExpr += activeLink[nodeNumber*i+j];
    duplexExpr += activeLink[nodeNumber*j+i];
    }
            halfDuplexConstraints.add(duplexExpr <= 1);
    duplexExpr.end();//when the expression is added to the constraints, we should end the expression.
    }
    patternGenModel.add(halfDuplexConstraints);
     
    // (25) v_ij+v_uw <= 1 + F[ij, uw]: physical constraint, whether two links can coexist
    IloExpr coexistExpr(env);
    for (i=0;i<nodeNumber;i++)
    {
    for (j=0;j<nodeNumber;j++)
    {
    if(i==j) continue;
    for(u=0;u<nodeNumber;u++)
    {
    for(v=0;v<nodeNumber;v++)
    {
    if(v==u || (u==i&&v==j)) continue;
    coexistExpr = activeLink[nodeNumber*i+j]+activeLink[nodeNumber*u+v];
    coexistConstraints.add(coexistExpr <= 1+conservativeCoexistanceTest(linkMatrix[i][j], linkMatrix[u][v]));
    }
    }
    }
    }
    patternGenModel.add(coexistConstraints);
     
    /* Variables for column generation method */
    IloNumArray dualValue(env, nodeNumber*nodeNumber);//pi_ij
    IloNumArray newPattern(env, nodeNumber*nodeNumber);//v_ij
    IloCplex subProblemSolver(patternGenModel); // The solver of sub problem 
    int count = 0;
     
    for(;;)//loop until the best result generate
    {
    caseINonCoopSolver.solve();
     
    for(i=0;i<nodeNumber;i++)
    {
    for(j=0;j<nodeNumber;j++)
    {
    ReducedCost.setLinearCoef(activeLink[i*nodeNumber+j], -linkMatrix[i][j].getRate() * caseINonCoopSolver.getDual(capacityConstraints[i*nodeNumber+j]));
    }
    }
     
    subProblemSolver.solve();
     
    cout << " step 4: " << " reduceCost " << subProblemSolver.getValue(ReducedCost) <<endl;
     
    if(subProblemSolver.getValue(ReducedCost) > -1.0e-6) break;//the reduced value is positive, then, the loop should end.
     
    cout << " step 5 " << activeLink.getSize() <<endl;
     
    for (int ii = 0; ii<nodeNumber*nodeNumber; ii++)
    {
    cout << " step 6 " <<endl;
       newPattern[ii] = subProblemSolver.getValue(activeLink[ii]);
    cout << " *********** i " << ii << "  patt  "  << subProblemSolver.getValue(activeLink[ii]) << "    " << newPattern[ii] <<endl;
    }

    After step 6, it stops and say that ERROR. However, with step 5, it is clear that activeLink.getSize() = 16. Why I cannot even get the value of activeLink[0]? Actually, it is set in my program as 0 after step 1.

    I cannot figure out where does this problem come out... Can anyone help me about this?

     


    #CPLEXOptimizers
    #DecisionOptimization


  • 2.  Re: Using empty IloNumVar handle

    Posted Thu September 19, 2013 02:56 AM
    Reply

    What is the statement that throws the exception?

    What looks suspicious in your code is this statement:

    activeLink[nodeNumber*i+j]=0;

    This will set the activeLink[nodeNumber*i+j] entry to an empty handle. If you ever attempt to use this handle you will get an "empty handle" error. What are trying to do here? Do you want to fix the variable to 0? If so then use activeLink[nodeNumber*i+j].setBounds(0, 0) instead.


    #CPLEXOptimizers
    #DecisionOptimization


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