Hi… maybe a simple solution is create a parameter that has the same value that the binary variable after solving the problem… something like this:

parameter xpar(i,j)

x.l(i,j)=xpar(i,j); (note that xpar(i,j) can be one or zero)

Then you should define the second model using a general formulation, i.e. all the equations that you have to use independient of the binary variable value, and then multiply the equations by the parameter defined in an appropiate way (by xpar(i,j) or (1-xpar(i,j)). As the parameter only must be one or zero:

if xpar(i,j)=0, then some equations will be like:

0=0 (allways true, “inactive constraints”)

and the others will be

f(i,j)=g(i,j) (“active constraints”).

hope this helps

Best regards

2009/4/27 Jens

Dear friends

I am a student and recently, I have been working on a small project

and try to solve a problem that I met. I just explain my problem in

very short:

set i /i1*i5/*

set j /j1j7/

bianary variable x(i,j)

after solving using MIP

display x.l

now my problem is: for example, if x(i1,j2),x(i2,j1) are the solution

of the model, and then I would like to use the rest sets i / i3,i4,i5/

and j /j3,j4,j5,j6,j7/ to programm another model, how can I fullfill ?

I ever tried to use abort$(x(i,j)=1) or not x(i,j)=1, but it doesn’t

work like what I expect. Could you be kind enough to suggest me what

I’m supposed to do?

## Best regards

Sincerely yours

Jens

\

Daniel AndrÃ©s Navia LÃ³pez

Ingeniero Civil QuÃmico

Mg.Sc.Ciencias de la IngenierÃa, MenciÃ³n IngenierÃa QuÃmica

626752875

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