Originally posted by: Ahlem

I have this code of the flexible job shop scheduling problem : 

/*Problem Description
-------------------

This problem is an extension of the classical Job-Shop Scheduling
problem (see SchedJobShop.java) which allows an operation to be
processed by any machine from a given set. The operation processing
time depends on the allocated machine. The problem is to assign each
operation to a machine and to order the operations on the machines
such that the maximal completion time (makespan) of all operations is
minimized.

------------------------------------------------------------ */

import ilog.concert.*;
import ilog.cp.*;

import java.io.*;
import java.util.List;
import java.util.ArrayList;

public class SchedCumul {

    static class DataReader {

        private StreamTokenizer st;

        public DataReader(String filename) throws IOException {
            FileInputStream fstream = new FileInputStream(filename);
            Reader r = new BufferedReader(new InputStreamReader(fstream));
            st = new StreamTokenizer(r);
        }

        public int next() throws IOException {
            st.nextToken();
            return (int) st.nval;
        }
    }

    static IloIntExpr[] arrayFromList(List<IloIntExpr> list) {
        return (IloIntExpr[])list.toArray(new IloIntExpr[list.size()]);
    }

    static class IntervalVarList extends ArrayList<IloIntervalVar> {
        public IloIntervalVar[] toArray() {
            return (IloIntervalVar[]) this.toArray(new IloIntervalVar[this.size()]);
        }
    }

    public static void main(String[] args) throws IOException {

        String filename = "../../../examples/data/jobshopflex_default.data";
        int failLimit = 10000;

        if (args.length > 0)
            filename = args[0];
        if (args.length > 1)
            failLimit = Integer.parseInt(args[1]);

        IloCP cp = new IloCP();
        DataReader data = new DataReader(filename);

        try {
            int nbJobs = data.next();
            int nbMachines = data.next();

            IntervalVarList[] machines = new IntervalVarList[nbMachines];
            for (int j = 0; j < nbMachines; j++)
                machines[j] = new IntervalVarList();
            List<IloIntExpr> ends = new ArrayList<IloIntExpr>();

            for (int i = 0; i < nbJobs; i++) {
                int nbOperations = data.next();
                IloIntervalVar prec = cp.intervalVar();
                for (int j = 0; j < nbOperations; j++) {
                    int nbOpMachines = data.next();
                    IloIntervalVar master = cp.intervalVar();
                    IntervalVarList members = new IntervalVarList();
                    for (int k = 0; k < nbOpMachines; k++) {
                        int m = data.next();
                        int d = data.next();
                        IloIntervalVar member = cp.intervalVar(d);
                        member.setOptional();
                        members.add(member);
                        machines[m - 1].add(member);
                    }
                    cp.add(cp.alternative(master, members.toArray()));
                    if (j > 0)
                        cp.add(cp.endBeforeStart(prec, master));
                    prec = master;
                }
                ends.add(cp.endOf(prec));
            }

            for (int j = 0; j < nbMachines; j++) {
                cp.add(cp.noOverlap(machines[j].toArray()));
            }

            IloObjective objective = cp.minimize(cp.max(arrayFromList(ends)));
            cp.add(objective);

            cp.setParameter(IloCP.IntParam.FailLimit, failLimit);
            System.out.println("Instance \t: " + filename);
            if (cp.solve()) {
                System.out.println("Makespan \t: " + cp.getObjValue());
            } else {
                System.out.println("No solution found.");
            }
        } catch (IloException e) {
            System.err.println("Error: " + e);
        }
    }
}

And i have attached the file data below. 

The code is correct and show me the makespan (completition time) but i would like to know how can i extract the end and start date of each operation and  the run time of each machine.

How can i do this? 

Please help me.

Regards. 

Since this is clearly related to constraint programming (and not mathematical programming), you should take your question to one of the constraint programming forums here.

Originally posted by: Ahlem

HI, 

Ok thanx you. But please what is the difference between  constraint programming and  mathematical programming ? 

Best regards.

http://ibmdecisionoptimization.github.io/docplex-doc/mp_vs_cp.html