[Cbc] Cuts and Integer Solutions in CBC

[Haroldo Santos]

John,

Tried using the setMustCallAgain(true) to my cut generator, but the problem
continues.

Haroldo

On Wed, May 21, 2008 at 7:05 AM, John J Forrest <jjforre at us.ibm.com> wrote:

> Haroldo,
>
> There may be bugs in the code but I think that you need to change some of
> the options in the CbcCutGenerator before you pass it to Cbc. In particular
> setMustCallAgain(true) will say keep adding cuts as long as there are any.
>
> The deafult will stop after a few passes, which is probably why you are
> seeing what is happening.
>
> John Forrest
>
> [image: Inactive hide details for "Haroldo Santos" ---05/20/2008 09:23:52
> AM---Hi All,]"Haroldo Santos" ---05/20/2008 09:23:52 AM---Hi All,
>
>
> From:
> "Haroldo Santos" <haroldo.santos at gmail.com>
> To:
> cbc at list.coin-or.org
> Date:
> 05/20/2008 09:23 AM
> Subject:
> [Cbc] Cuts and Integer Solutions in CBC
> ------------------------------
>
>
>
> Hi All,
>
> I'm working with a MIP with an exponential number of constraints. To define
> the problem we need this huge amount of rows.
> So, I defined a cbcmodel with a small subset of these constraints and added
> an specialization of CglCutGenerator to dynamically insert the other rows,
> as needed.
> However, in the first iterations cbcmodel finds an Integer solution and
> stops the search, even if new cuts were added.
> Note that these "cuts" are not cuts in the traditional way: they do not cut
> fractional solutions. Instead, they define the problem.
> Is there any way to tell cbc that if new cuts were added, it must continue
> the search ?
> I think that in CPLEX this can be done by the so called "lazy constraints".
>
> Best regards,
>
> Haroldo
>
> --
> ===============================================================
> Haroldo Gambini Santos*
> **http://www.ic.uff.br/~hsantos* <http://www.ic.uff.br/%7Ehsantos>*
> **hsantos at ic.uff.br* <hsantos at ic.uff.br>
>
> Instituto de Computacao - Universidade Federal Fluminense
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>
>


-- 
===============================================================
Haroldo Gambini Santos
http://www.ic.uff.br/~hsantos
hsantos at ic.uff.br
Instituto de Computacao - Universidade Federal Fluminense
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