Originally posted by: SystemAdmin

[wingbow said:]

To set an objective function to be:
[color=blue][i]Min x[0][0][0][/i][/color]

I include the following in the Java code:
[color=brown]IloLinearNumExpr objFcn = model.linearNumExpr();
objFcn.addTerm(1,x[0][0][0]);
model.addMinimize(objFcn);[/color]

But the following error messages are shown during program run:
[color=green]Exception in thread "main" java.lang.NullPointerException
        at ilog.cplex.CpxLinearExpr.unmarkVars(CpxLinearExpr.java:377)
        at ilog.cplex.CpxLinearExpr.removeDuplicates(CpxLinearExpr.java:484)
        at ilog.cplex.CpxObjective.setExpr(CpxObjective.java:87)
        at ilog.cplex.CpxObjective.<init>(CpxObjective.java:283)
        at ilog.cplex.IloCplex.objective(IloCplex.java:534)
        at ilog.cplex.IloCplex.addObjective(IloCplex.java:565)
        at ilog.cplex.IloCplex.addMinimize(IloCplex.java:574)[/color]

Can anyone help????
Thanks a lot!!
#DecisionOptimization
#MathematicalProgramming-General

Originally posted by: SystemAdmin

[Didier Vidal said:]

How did you initialize the x array ? The error might be that x[0][0][0] = null....

Didier.
#DecisionOptimization
#MathematicalProgramming-General

Originally posted by: SystemAdmin

[wingbow said:]

Do we need to initialize??
What I did is to declare:
[color=blue]
IloIntVar[][][]  x;
x = new IloIntVar[4][4][2];[/color]
#DecisionOptimization
#MathematicalProgramming-General

Originally posted by: SystemAdmin

[wingbow said:]

I solved the problem!
For the reference of future users, we can initialize the Ilo-variables by statements like:
[color=blue]x[0][0][0]=model.intVar(0,1);[/color]
#DecisionOptimization
#MathematicalProgramming-General