[AMPL 1842] divergance problem

[humaira fazal]

Hello

Can anyone guide me how to stop the iterations when the constraints are no more satisfied.
My model is like that
set N:=1..4
param e1>=0;
param e2>=e1;
var F{j in N}=.........
var eps;
var del=sum{j in N} eps[j];
maximize f: e2*sum{i in N} F[j];
subject to e1:del>=e1;
subject to e2:del<=e2;

It is ok untill del>e1 but when del=e1, the message appears unbounded (or badly scaled) problem.

So what I have to do to stop iteration when constraints are no more satisfied or become divergent.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group.
To post to this group, send email to ampl@...
To unsubscribe from this group, send email to ampl-unsubscribe@...
For more options, visit this group at http://groups.google.com/group/ampl?hl=en
-~----------~----~----~----~------~----~------~--~---

[Robert Fourer-2]

Some parts of this message have been removed. Learn more about Nabble's security policy.

I do not understand your problem clearly.  When the solver determines that the problem is "unbounded (or badly scaled)" then it stops immediately; you do not have to do anything special to stop the iterations.

 

If you would post the rest of the declaration of var F and the values of e1 and e2 and you used, then some subscribers to this group might be able to provide more help.  From the form of the error message I would guess you are using MINOS, but if not then the choice of solver would also be helpful.

 

Bob Fourer

4er@...

 

 

---

From: ampl@... [mailto:ampl@...]

On Behalf Of humaira fazal
Sent: Thursday, June 19, 2008 7:31 AM
To: ampl@...
Subject: [AMPL 1842] divergance problem

 

Hello

Can anyone guide me how to stop the iterations when the constraints are no more satisfied.
My model is like that
set N:=1..4
param e1>=0;
param e2>=e1;
var F{j in N}=.........
var eps;
var del=sum{j in N} eps[j];
maximize f: e2*sum{i in N} F[j];
subject to e1:del>=e1;
subject to e2:del<=e2;

It is ok untill del>e1 but when del=e1, the message appears unbounded (or badly scaled) problem.

So what I have to do to stop iteration when constraints are no more satisfied or become divergent.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group.
To post to this group, send email to ampl@...
To unsubscribe from this group, send email to ampl-unsubscribe@...
For more options, visit this group at http://groups.google.com/group/ampl?hl=en
-~----------~----~----~----~------~----~------~--~---