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Re: [Help-glpk] lp/mip preprocessor api


From: Andrew Makhorin
Subject: Re: [Help-glpk] lp/mip preprocessor api
Date: Wed, 09 May 2018 15:09:52 +0300

On Mon, 2018-05-07 at 11:08 -0300, Luiz Rafael dos Santos wrote:
> Dear Andrew,
> 
> 
> As I said to you before, I was trying to make the new preprocessor API
> of GLPK work on Julia (http://github.com/JuliaOpt/GLPK.jl). Indeed, it
> worked like a charm!  Thanks for that
> 
> 
> However now, on the multiple test we run on GLPK.jl, the
> `ios_del_row()` routine is not working. 
> 
> 
> I believe this is happening because now, on version 4.65, at
>  glpios01.c, lines 1550-1553: 
> ```#ifdef NEW_LOCAL /* 02/II-2018 */
> void ios_del_row(glp_tree *tree, IOSPOOL *pool, int i)
> {     /* remove row (constraint) from the cut pool */
>       xassert(0);
> }
> #elsedef```
> the routine is not defined anymore. 
> 
> 
> Is this a feature that will become obsolete and will be removed?
> 
> 
> Is this a bug? 

Neither. ios_del_row is just not reimplemented for NEW_LOCAL. However,
now IOSPOOL which is a synonym for glp_pool is also a synonym for
glp_prob (i.e. cut pool is implemented as an ordinary problem object).
So, if needed, you may replace it with the following routine:

void ios_del_row(glp_tree *tree, IOSPOOL *pool, int i)
{     /* remove row (constraint) from the cut pool */
      int num[2];
      num[1] = i;
      glp_del_rows(pool, 1, num);
      return;
}

See, for example, ios_clear_pool below in the same file.


Best regards,

Andrew Makhorin

> 
> 
> Best regards,
> 
> 
> Rafa
> 
> 
> 
> 
> -- 
> Luiz Rafael dos Santos
> Departamento de Matemática
> Centro de Blumenau
> Universidade Federal de Santa Catarina 
> Blumenau/SC/Brasil
> Fone: +55 47 3232 5184 / +55 48 3721 3384
> Voip: +55 48 3363 2267
> 
> > Em 19 de mar de 2018, à(s) 20:52, Luiz Rafael dos Santos
> > <address@hidden> escreveu:
> > 
> > That’s great. 
> > 
> > 
> > Thank Andrew for your work with GLPK.
> > 
> > 
> > Cheers,
> > 
> > 
> > Rafa
> > -- 
> > Luiz Rafael dos Santos
> > Departamento de Matemática
> > Centro de Blumenau
> > Universidade Federal de Santa Catarina 
> > Blumenau/SC/Brasil
> > Fone: +55 47 3232 5184 / +55 48 3721 3384
> > Voip: +55 48 3363 2267
> > 
> > > Em 19 de mar de 2018, à(s) 14:52, Andrew Makhorin <address@hidden>
> > > escreveu:
> > > 
> > > Hi Luiz,
> > > 
> > > 
> > > > I’m Prof. Rafael Santos from University of Santa Catarina,
> > > > Brazil.
> > > > I would like to use your LP/MIP preprocessor API together with
> > > > Julia
> > > > GLPK, for a paper I’m writing on a new method for LP that makes
> > > > use of
> > > > a Augmented Lagrangian method. 
> > > 
> > > Thank you for your interest in glpk.
> > > 
> > > > Do you have any timetable to release such API?
> > > 
> > > This feature is already implemented in glpk 4.65; please see
> > > http://lists.gnu.org/archive/html/help-glpk/2018-02/msg00009.html
> > > 
> > > 
> > > Best regards,
> > > 
> > > Andrew Makhorin
> > > 
> > > 
> > > 
> > 
> > 
> 
> 





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