After zero iterations CPLEX 12.8 concluded that Planningprogram is unbounded.

45 views
Skip to first unread message

İNCİ

unread,
Apr 18, 2019, 7:45:35 AM4/18/19
to AIMMS - The Modeling System
Hello, when I try the run this model. 
1-I'm getting a warning as "Warning_duplicate_column".
2-limit_reported_duplicate_column
3-Planningprogram is unbounded
Could you tell me what is the problem?

Model Main_Inci {
    Set ID {SubsetOf: Integers; Index: i;    }
    Set Scenario {SubsetOf: Integers; Index: j;    }
    Set Periods {SubsetOf: Integers; Index: t;    }
    Parameter Area {IndexDomain: (i,j,t);    }
    Parameter RecAft {IndexDomain: (i,j,t);    }
    Parameter WregAft {IndexDomain: (i,j,t);   }
    Parameter EduAft {IndexDomain: (i,j,t);    }
 
    DeclarationSection Decisionvariable {Variable x {IndexDomain: (i,j);Range: free;}}
    DeclarationSection Accountingvariables {Variable totalutility {IndexDomain: Range: free;
            
Definition: sum [(i,j,t), Area(i,j,t)*RecAft(i,j,t)*x(i,j)+ Area(i,j,t)*WregAft(i,j,t)*x(i,j)+Area(i,j,t)*EduAft(i,j,t)*x(i,j)];} }

DeclarationSection Objectivefunction {MathematicalProgram Planningprogram {Direction: 
maximize;totalutility 
Constraints: AllConstraints;
Variables: AllVariables;
Type: Automatic;
   
    Procedure MainExecution {
        Body: {solve Planningprogram ;
            if (Planningprogram.ProgramStatus <> 'Optimal') then
              empty x; 
            endif; }}


Warning: The columns "x(339,11)" and "x(339,49)" are equal in the generated mathematical program "Planningprogram". This may lead to non-unique solutions.  For more information regarding potential causes and consequences, see the help associated with the option "Warning_duplicate_column".
Warning: The columns "x(339,10)" and "x(339,11)" are equal in the generated mathematical program "Planningprogram". This may lead to non-unique solutions.  For more information regarding potential causes and consequences, see the help associated with the option "Warning_duplicate_column".
Warning: The columns "x(339,9)" and "x(339,10)" are equal in the generated mathematical program "Planningprogram". This may lead to non-unique solutions.  For more information regarding potential causes and consequences, see the help associated with the option "Warning_duplicate_column".
Warning: Only 3 out of 50495 duplicate column warnings were reported.  See also option limit_reported_duplicate_column_row_warnings.
Warning: After zero iterations CPLEX 12.8 concluded that Planningprogram is unbounded.

Luis Pinto

unread,
Apr 18, 2019, 8:40:38 AM4/18/19
to AIMMS GoogleGroups
Hello,

1-I'm getting a warning as "Warning_duplicate_column".

This means you have identical variables in your model. Without data, can't really say which ones those would be but unless this is unexpected, it isn't necessarily an issue.

2-limit_reported_duplicate_column

When you do get the above error, it tells you which are the duplicates. If there are too many, it'll show you subset. I think this is just to say it show you less than all of the duplicates.

3-Planningprogram is unbounded

Your program is unbounded, that is, the solution to it is +inf (since it's a maximization problem).
Either your variable should be limited (nonnegative? or bounded?) or there are missing constraints. Actually, it seems you don't have any constraints (a part from the defined variable).

Best regards,

--
You received this message because you are subscribed to the Google Groups "AIMMS - The Modeling System" group.
To unsubscribe from this group and stop receiving emails from it, send an email to aimms+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/aimms/f3cb6a57-55d0-4c34-9a31-3ef8a4f481a9%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

İNCİ ÇAĞLAYAN

unread,
Apr 22, 2019, 2:33:52 AM4/22/19
to ai...@googlegroups.com
hello, thank you so much for your reply.
1-"This means you have identical variables in your model. Without data, can't really say which ones those would be but unless this is unexpected, it isn't necessarily an issue."

I don't have identical variables. Already, I have two variable and they are different. But I have identical data. For example "EduAft_111=0.5 and EduAf_128=0.5"
it should not be an issue...

2-When you do get the above error, it tells you which are the duplicates. If there are too many, it'll show you subset. I think this is just to say it show you less than all of the duplicates.

I guess it is not an issue.

3-Your program is unbounded, that is, the solution to it is +inf (since it's a maximization problem). Either your variable should be limited (nonnegative? or bounded?) or there are missing constraints. Actually, it seems you don't have any constraints (a part from the defined variable).

I defined the variable (Xi,j) in both ways (nonnegative or bounded) and tried again. I got a warning "After zero iterations the preprocessor of CPLEX 12.8 concluded that Planningprogram is infeasible or unbounded." When I changed " totalutility" variables range as nonnegative I am getting the same warning.
yes, I did not add constraints to see the results without restriction. is this an issue? 

Best regards,

Luis Pinto <luis...@gmail.com>, 18 Nis 2019 Per, 15:40 tarihinde şunu yazdı:
To view this discussion on the web visit https://groups.google.com/d/msgid/aimms/CABkVXWeRFK2c5ADv56cjgeRzOuo0qPCk8365Y12ucc0sYOFXQQ%40mail.gmail.com.

Mohan

unread,
Apr 22, 2019, 2:42:57 AM4/22/19
to AIMMS - The Modeling System
1-"This means you have identical variables in your model. Without data, can't really say which ones those would be but unless this is unexpected, it isn't necessarily an issue."

I don't have identical variables. Already, I have two variable and they are different. But I have identical data. For example "EduAft_111=0.5 and EduAf_128=0.5"
it should not be an issue...

This is your objective function. Depending on the values of RecAft(i, j, t), WregAft(i, j, t) and EduAft(i, j, t) - some combinations of the variable x(i, j) will be equivalent - you can swap their values and still have the same objective function.

sum [(i,j,t), Area(i,j,t)*RecAft(i,j,t)*x(i,j)+ Area(i,j,t)*WregAft(i,j,t)*x(i,j)+Area(i,j,t)*EduAft(i,j,t)*x(i,j)];} }

The duplicate columns warning can be ignored but is an indication that the model could be formulated better. They are quite common but as you don't have any constraints in this model, there are so many (50, 000 + ).

3-Your program is unbounded, that is, the solution to it is +inf (since it's a maximization problem). Either your variable should be limited (nonnegative? or bounded?) or there are missing constraints. Actually, it seems you don't have any constraints (a part from the defined variable).

I defined the variable (Xi,j) in both ways (nonnegative or bounded) and tried again. I got a warning "After zero iterations the preprocessor of CPLEX 12.8 concluded that Planningprogram is infeasible or unbounded." When I changed " totalutility" variables range as nonnegative I am getting the same warning.
yes, I did not add constraints to see the results without restriction. is this an issue?

totalutility is your objective function. It must be a free variable.

Again, you only have one variable x(i, j) and your math program is maximize total utility. You should have at least a constraint or range saying that x(i, j) <= k(i ,j) where k is a constant. If x is nonnegative, it will still be unbounded because all x(i,j) can assume positive infinity. That will be the case until you specify an upper bound for all combinations of x(i, j) or add constraints to your model.
To unsubscribe from this group and stop receiving emails from it, send an email to aimms+unsubscribe@googlegroups.com.

--
You received this message because you are subscribed to the Google Groups "AIMMS - The Modeling System" group.
To unsubscribe from this group and stop receiving emails from it, send an email to aimms+unsubscribe@googlegroups.com.

İNCİ ÇAĞLAYAN

unread,
Apr 23, 2019, 8:15:17 AM4/23/19
to ai...@googlegroups.com
Dear Mohan
Thank you so much for your reply. As you say, When we add a constraint, the model ran.
Best Regards

Mohan <aimms.m...@gmail.com>, 22 Nis 2019 Pzt, 09:42 tarihinde şunu yazdı:
To unsubscribe from this group and stop receiving emails from it, send an email to aimms+un...@googlegroups.com.

--
You received this message because you are subscribed to the Google Groups "AIMMS - The Modeling System" group.
To unsubscribe from this group and stop receiving emails from it, send an email to aimms+un...@googlegroups.com.

--
You received this message because you are subscribed to the Google Groups "AIMMS - The Modeling System" group.
To unsubscribe from this group and stop receiving emails from it, send an email to aimms+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/aimms/217fe74e-b87f-40c8-b4f0-d9f5d2dfcf47%40googlegroups.com.
Reply all
Reply to author
Forward
0 new messages