Re: [eclipse-clp-users] 'Problem is infeasible!' in eplex goes to stdout

From: Sergii Dymchenko <kit1980_at_...6...>
Date: Wed, 10 Sep 2014 22:07:13 -0700

Do you have any estimate when you will be able to update the
Cbc we use by compiling it with the macro to suppress the printing of
these messages?

I'd want to publish an article that have some examples using eplex, and I'd
like the examples to work with the latest stable ECLiPSe version if someone
wants to test.


On Thu, Aug 28, 2014 at 10:59 AM, Kish Shen <kisshen@...5...> wrote:

> Hi Sergii,
> I should have updated on this earlier, but I was waiting to see if I got
> any responses from the Cbc mailing list to my post there about this
> problem, but as yet there is nothing...
> On 20/08/2014 08:58, Sergii Dymchenko wrote:
> > Hi,
> >
> > I've investigated the issue further and found that the message appears
> not
> > for all infeasible instances, but only for some of them. The issue
> present
> > in the version 6.1 #191 and not present in the version 6.1 #164 - so it
> was
> > introduced sometime in between.
> The problem was as I suspected: CbcSolver (the MIP solver used in this
> case) does print the 'Problem is infeasible!' directly to stdout
> (std::cout -- the code is written in C++) in several places, and there
> are also other messages that are printed to stdout. I am not sure why it
> is done this way, as most outputs are handled via their message handler,
> which is what the eplex output channels are connected to.
> I updated the Cbc solver used with eplex in March this year, and I
> assume this is the reason for why you see the message only in the recent
> ECliPSe version.
> The printing of 'Problem is infeasible!' message can be excluded from
> compiling Cbc, as the source for it are enclosed by a macro that allow
> the printing to be excluded from the compile. However, not all messages
> sent to std:cout in CbcSolver are enclosed by this macro, so unless the
> Cbc source is modified, messages can still be sent to stdout -- although
> these messages seems to be related to using CbcSolver as a stand-alone
> solver, so hopefully they will not be seen when CbcSolver is called from
> a program, as we do in eplex.
> As I mentioned, I posted a message to the Cbc mailing list asking about
> these messages on 21 August, but have received no responses. I will try
> a follow-up post, and if I still don't hear anything, I will update the
> Cbc we use by compiling it with the macro to suppress the printing of
> these messages.
> Cheers,
> Kish
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Received on Thu Sep 11 2014 - 05:07:20 CEST

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