[Bug-glpk] [Fwd: Re: glpk prints warnings which lead to failing sagemath tests]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Tobias Hansen <address@hidden>
To: Andrew Makhorin <address@hidden>
Cc: Sébastien Villemot <address@hidden>, address@hidden,
address@hidden
Subject: Re: glpk prints warnings which lead to failing sagemath tests
Date: Wed, 28 Feb 2018 12:01:48 +0100

On 02/28/2018 09:51 AM, Andrew Makhorin wrote:
> On Mon, 2018-02-26 at 18:56 +0100, Tobias Hansen wrote:
>> On 02/26/2018 04:46 PM, Andrew Makhorin wrote:
>>> On Mon, 2018-02-26 at 12:00 +0100, Sébastien Villemot wrote:
>>>> Dear GLPK maintainer,
>>>>
>>>> I received the attached bug report and patch for the glpk package in 
>>>> Debian.
>>>>
>>>> What’s your take on this? Should I apply the patch, or is this something 
>>>> that
>>>> should better be fixed at the sagemath level?
>>>>
>>>> Best,
>>>>
>>>> P.S.: please keep all addresses in CC when replying.
>>> Thank you for your bug report.
>>>
>>> Could you please explain in more details how glpk is tested? Both glpk
>>> lp and mip solvers issue many messages to the standard output, so it is
>>> unclear to me how some of the messages may affect the tests.
>>>
>>> Andrew Makhorin
>> Hi,
>>
>> one example that I checked was using the mip solver (not sure if other
>> solvers are affected) with msg_lev set to GLP_MSG_OFF. Normally there
>> is no terminal output, now there is the message "Long-step dual
>> simplex will be used". GLPK is used from a Python program which checks
>> the terminal output in its test suite.
> GLP_MSG_OFF is not a relevant option to disable terminal/stdout output. 
> Please use glp_term_out(GLP_OFF) and glp_term_out(GLP_ON) instead--these
> calls disable/enable terminal output on a lower level independently on
> options passed to the solvers.
>
> Besides, as was noticed by Heinrich, it is not a good idea to parse the
> terminal output to test glpk (what namely do you want to test in such a
> way?).
>
> Best regards,
>
> Andrew Makhorin

Comments from the sage ticket https://trac.sagemath.org/ticket/24824#ticket

Comment (by jdemeyer):

 Replying to [comment:5 thansen]:
 > GLP_MSG_OFF is not a relevant option to disable terminal/stdout output.

 It's not our goal to completely disable terminal output. We still want to
 see error messages for example.

Comment (by jdemeyer):

 It would also be good to know what the message "Long-step dual simplex
 will be used" means. Is it supposed to be a warning to say that we are
 doing something wrong?



>
>> Best,
>> Tobias Hansen
>>
>>
>>>
>>>> MHTML Document attachment (Bug#891465: glpk: prints warnings which
>>>> lead to failing sagemath tests)
>>>>> -------- Forwarded Message --------
>>>>> From: Tobias Hansen <address@hidden>
>>>>> Reply-to: Tobias Hansen <address@hidden>, address@hidden
>>>>> To: address@hidden
>>>>> Subject: Bug#891465: glpk: prints warnings which lead to failing
>>>>> sagemath tests
>>>>> Date: Sun, 25 Feb 2018 20:54:19 +0100
>>>>>
>>>>> Source: glpk
>>>>> Version: 4.65-1
>>>>> Severity: normal
>>>>> Tags: patch
>>>>>
>>>>> Hi there,
>>>>>
>>>>> since version 4.65 glpk started to frequently print the message
>> "Long-step dual simplex will be used", leading to many failed tests
>> for sagemath and sagemath failing to build. Not sure if it's a bug in
>> glpk but it seems to me it shouldn't print this. Could you maybe
>> deactivate the messages to allow sagemath to build?
>>>>> Best,
>>>>> Tobias
>>
>>
>