Originally posted by: Torben-Ger-1988

Hey Guys,

my Knapsackproblem is looking right now as showed down there...

I'd like to change it a little bit. At the moment there is a limited capacity. I'd like to change it that there is an unlimited capacity and instead of V[] I'd like to get a nw decision var called m

Which means i'd like to put each think into my Knapsack for exactly 1 time and I'd like to know the value of all of my parts and the needed more capacity.

But i am not sure. Changed the structure and never received a proper result. Thanks for your help

import java.util.HashMap;
 
import ilog.concert.IloException;
import ilog.concert.IloLinearNumExpr;
import ilog.concert.IloNumVar;
import ilog.concert.IloNumVarType;
import ilog.cplex.IloCplex;
 
public class Fillit{ 

     public static void main(String[] args) throws IloException {
          // TODO Auto-generated method stub
          double valuesObj[] = {4.0, 2.0, 3.0, 1.0};
          double values2[][] = {{2,3},{2,6}};
         
          IloCplex cplex = new IloCplex();
          IloLinearNumExpr obj = cplex.linearNumExpr();
          IloNumVar V[] = new IloNumVar[4];
          /*
          IloNumVar P[][] = new IloNumVar[4][4];
          P[0][0] = cplex.numVar(0, Double.POSITIVE_INFINITY, IloNumVarType.Bool, "");
          obj.addTerm(P[0][0], values2[0][0]);
          */
         
          V[0] = cplex.numVar(0, Double.POSITIVE_INFINITY, IloNumVarType.Bool, "V( 0 )");
          V[1] = cplex.numVar(0, Double.POSITIVE_INFINITY, IloNumVarType.Bool, "V( 1 )");
          V[2] = cplex.numVar(0, Double.POSITIVE_INFINITY, IloNumVarType.Bool, "V( 2 )");
          V[3] = cplex.numVar(0, Double.POSITIVE_INFINITY, IloNumVarType.Bool, "V( 3 )");
         
          for(int index = 0; index < valuesObj.length; index++){
                obj.addTerm(V[index], valuesObj[index]);
          }
          /*
          obj.addTerm(V[0], 4.0);
          obj.addTerm(V[1], 2.0);
          obj.addTerm(V[2], 3.0);
          obj.addTerm(V[3], 1.0);
          */
          cplex.addMaximize(obj);
         
          IloLinearNumExpr lin = cplex.linearNumExpr();
          lin.addTerm(V[0], 3.0 );
          lin.addTerm(V[1], 4.0 );
          lin.addTerm(V[2], 1.0 );
          lin.addTerm(V[3], 2.0 );
          cplex.addLe(lin, 7.0, "constraint");
         
          if( cplex.solve() ){
                cplex.output().println("Solution status = " + cplex.getStatus());
                cplex.output().println("Solution value = " + cplex.getObjValue());
               
                System.out.println("V[0] " + cplex.getValue(V[0]));
                System.out.println("V[1] " + cplex.getValue(V[1]));
                System.out.println("V[2] " + cplex.getValue(V[2]));
                System.out.println("V[3] " + cplex.getValue(V[3]));
          }
          else{
                cplex.output().println("Solution status = " + cplex.getStatus());
          }
     }
 
}

Hi,

if you want to start in OPL you have an example at

CPLEX_Studio1262\opl\examples\opl\knapsack

regards

Originally posted by: Torben-Ger-1988

Hey Alex,

i'm not quiet sure if i described my problem good enough.

The Knapsack is already wrking,its in JAVA Code.

I'd like to keep in in JAVA Code and just extend the Knapsackproblem a little bit.

Thanks for your reply