RE: [Help-glpk] A new text-based data format for GLPK

[Nigel Galloway]

Thanks for the reference. I have used osi for my programming api for a while 
now and this will be a good addition.

Taken together with the paper Displaying Linear Programs and Their
Solutions With XML and SVG this makes a good case for an XML format.

Formatted text is really somthing which gives instructions to notepad on how to 
display something which is humanly readable. Missing from the OS distribution 
is something to make the OSrL humanly readable in a web browser. Perhaps OS 
should include some example xsl files for client side display. I would probably 
use php and do the final stage server side as the more modern approach. Without 
these Robbie has a point that the output is less immeadiatly humanly readable 
than the formatted text.

Obviously a web browser provides a much richer display environment than 
notepad. Font Style, Colour, and Graphics as well as layout.

In addition XML is extensible. That is tags can be added to include new 
information as required, without affecting any tools already using the format. 
gawk is a good tool for transforming formatted text, but if the format is 
modified even slightly its unlikly that any script written in gawk will still 
produce good results.



> ----- Original Message -----
> From: "Robert Fourer" <address@hidden>
> To: address@hidden
> Cc: "'Nigel Galloway'" <address@hidden>
> Subject: RE: [Help-glpk] A new text-based data format for GLPK
> Date: Sun, 3 Jan 2010 10:16:19 -0600
> 
> 
> 
> See also http://projects.coin-or.org/OS for the description of a project
> that defines XML representations of optimization problems, solutions, and
> related information and provides libraries for working with them.  It would
> not be hard to integrate GLPK into this framework.
> 
> Bob Fourer
> Industrial Engineering & Management Sciences
> Northwestern University
> address@hidden
> 
> 
> > -----Original Message-----
> > From: address@hidden [mailto:help-
> > address@hidden On Behalf Of Nigel
> > Galloway
> > Sent: Sunday, January 03, 2010 8:32 AM
> > To: address@hidden
> > Subject: Re: [Help-glpk] A new text-based data format for GLPK
> >
> > 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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>


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