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Re: [Help-glpk] A new text-based data format for GLPK
From: |
Nigel Galloway |
Subject: |
Re: [Help-glpk] A new text-based data format for GLPK |
Date: |
Sun, 3 Jan 2010 15:31:37 +0100 |
Or (more sensibly?) XML can be converted to formatted text for those who
require it.
The following may be interesting(Displaying Linear Programs and Their Solutions
With XML and SVG):
http://portal.acm.org/citation.cfm?id=1082118
> ----- Original Message -----
> From: "Robbie Morrison" <address@hidden>
> To: "GLPK help" <address@hidden>
> Subject: [Help-glpk] A new text-based data format for GLPK
> Date: Thu, 31 Dec 2009 16:44:28 +0100
>
>
>
> Hello Andrew, GLPK users
>
> > ------------------------------------------------------------
> > To: Robbie Morrison <address@hidden>
> > Subject: Re: [Help-glpk] Processing glpsol output with R
> > Message-ID: <address@hidden>
> > From: Andrew Makhorin <address@hidden>
> > Date: Tue, 29 Dec 2009 20:50:17 +0300
> > ------------------------------------------------------------
> >
> > Hi Robbie,
> >
> >> > [As a suggestion to Andrew, it might be cleaner for the
> >> > '--write' option to state something like "LP" or "MIP"
> >> > in the opening line to unambiguously indicate the
> >> > problem class -- or perhaps even give a finer
> >> > resolution, for instance "mixed-integer", "mixed-01",
> >> > etc). Note too that the now depreciated 'lpx_get_class'
> >> > call used to provide at least some of this information.]
> >
> > Thank you for the suggestion.
> >
> > I think that it is reasonable to include in glpk some api
> > routines to read and write lp/mip instances as well as
> > basic/interior-point/mip solution from/to a text file in a
> > more convenient format, which would include row/column
> > names. A DIMACS-like format seems to me most suitable,
> > because it allows easily using standard text utilities like
> > sed, gawk, etc. Using XML seems to me much more tricky and
> > much less convenient for processing out of glpk.
> >
> > Andrew Makhorin
>
> I took the liberty of opening a new thread!
>
> I agree that structured text, when compared to XML, can be
> easier for humans to read (particularly for test instances)
> and that text is certainly more convenient to interpret and/or
> modify using basic utilities and common scripting languages.
>
> Indeed XML should really be parsed and it is considered very
> poor form to apply grep and friends to XML.
>
> The conversion of structured text to XML always remains an
> option for those who require XML.
>
> With regard to the DIMACS-like format, I guess you are
> referring to their CNF or conjunctive normal form.
>
> http://en.wikipedia.org/wiki/Conjunctive_normal_form
>
> I cannot comment on the appropriateness of this choice,
> beyond to say that the format seems to be current and that
> other projects are offering support for it. It also appears
> that several stand-alone format translators are available.
>
> Having experimented with XML support in C++ applications,
> I acknowledge that the coding overhead is higher. In
> addition, you would need to select a suitable GPL'ed
> C-based XML library for the XML option.
>
> Other people have views ??
>
> with best wishes
> Robbie
> ---
> Robbie Morrison
> PhD student -- policy-oriented energy system simulation
> Technical University of Berlin (TU-Berlin), Germany
> University email (redirected) : address@hidden
> Webmail (preferred) : address@hidden
> [from IMAP client]
>
>
>
>
> _______________________________________________
> Help-glpk mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/help-glpk
>
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- Re: [Help-glpk] A new text-based data format for GLPK,
Nigel Galloway <=