[Couenne] how to make couenne cut itself

[Pietro Belotti]

Dear Mahbube,

>  Why “bonmin: Optimal” in the last line?

That is a wrong output, and it has been fixed in the latest stable  
release. Couenne uses part of the Bonmin code to interface with the  
Cbc branch-and-bound, and I have overlooked this output until recently.

> Then I run the program with another input (which has binary   
> variables) and this time the optimum value is exactly the same as   
> MINLP but after 15365 second, it is still running and I don’t know   
> how to stop it to check other results.
> I simply typed:
> Option solver couenne;
> Model *.mod; Data *.dat; Solve;
> Do I need another command to make it stop?

If you hit Ctrl-C at any time, the optimization should stop, although  
I'm not sure whether you'll be able to read the best solution found up  
to that point. Another option is to set a time limit (for example, an  
hour) in the option file couenne.opt (which has to be in the same  
directory where you are running AMPL) as follows:

time_limit 3600

Further information can be found in the user's manual:

https://projects.coin-or.org/Couenne/browser/trunk/Couenne/doc/couenne-user-manual.pdf?format=raw

Hope this helps. In the future, please direct these questions to the  
Couenne mailing list: couenne at list.coin-or.org

Best regards,
Pietro

_________________________________________
Pietro Belotti, Lehigh University
Dept. of Industrial & Systems Engineering
200 W Packer Ave, Bethlehem PA 18015.
phone: 610-758-3865   fax: 610-758-4886
email: belotti at lehigh.edu
web:   http://www.lehigh.edu/~pib208


On 07/03/2009, mahbube zeraatzade <mzzade at yahoo.com> wrote:

> Dear Pietro,
> I thank you again for your help. I have another problem running the couenne.
> 'Couenne' returns the same results as MINLP but at the end I see:
> Cbc004I  Integer solution of 1386.14 found after 66653 iterations   
> and 3182 nodes<234.78 seconds>
> Cbc0001I Search completed – best objective 1386.1410665…, took   
>  66653 iterations and 3182 nodes <234.83 second >
> Cbc0035I Maximum depth 137, 0 variables fixed on reduced cost
> Couenne convexifier cuts was tried 3212 times and created 352796   
> cuts of which 29879 were active after adding round of cuts
>                         “Finished”
> binmin: Optimal
>  
>  Why “bonmin: Optimal” in the last line?
>  
> Then I run the program with another input (which has binary   
> variables) and this time the optimum value is exactly the same as   
> MINLP but after 15365 second, it is still running and I don’t know   
> how to stop it to check other results.
> I simply typed:
> Option solver couenne;
> Model *.mod; Data *.dat; Solve;
> Do I need another command to make it stop?
>  I thank you in advance,
>  
> Best regards,
> Mahbube


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