### Unbounded Solution

Posted:

**Fri Nov 24, 2017 6:54 am**Hi All,

I am trying to decompose model(may be it is also called multi-objective problem ) in such a way a that value of variables estimated in first sub model can be used for second sub model. But in doing so second model leading to infeasible solution due to unbounded. Please give me suggestions how to formulate this problem so that variable optimize in sub problem 1 use information as a input for second model.

Below is code

*Model 1

positive variable f1,f2, x,y;

variable f3 ;

equation

a1,a2,a3;

a1.. f1 =e= 10*x+9*y ;

a2.. f2 =e= 9*x+8*y ;

a3.. f3 =e= f1-f2;

x.lo = 1;

y.lo = 1;

x.up = 5;

y.up = 3 ;

model m /a1,a2,a3/;

solve m maximizing f3 using lp ;

* Model 2

scalar IR /1.1/

variable f4 ;

equation a4;

a4.. f4 =e= f3/IR**IR;

model m1 /a4/;

solve m1 maximizing f4 using lp;

I am trying to decompose model(may be it is also called multi-objective problem ) in such a way a that value of variables estimated in first sub model can be used for second sub model. But in doing so second model leading to infeasible solution due to unbounded. Please give me suggestions how to formulate this problem so that variable optimize in sub problem 1 use information as a input for second model.

Below is code

*Model 1

positive variable f1,f2, x,y;

variable f3 ;

equation

a1,a2,a3;

a1.. f1 =e= 10*x+9*y ;

a2.. f2 =e= 9*x+8*y ;

a3.. f3 =e= f1-f2;

x.lo = 1;

y.lo = 1;

x.up = 5;

y.up = 3 ;

model m /a1,a2,a3/;

solve m maximizing f3 using lp ;

* Model 2

scalar IR /1.1/

variable f4 ;

equation a4;

a4.. f4 =e= f3/IR**IR;

model m1 /a4/;

solve m1 maximizing f4 using lp;