[Coin-discuss] Benchmark Instances & code for format conversions

[Robert Fourer]

There's a group working on a standard based on XML, with the syntax of the
standard precisely defined by an XML schema.  An API is to be provided for
reading and writing this format, as well as for a related standard data
structure that represents optimization problem instances in memory.  General
nonlinear expressions are included, and a variety of other extensions are at
intermediate stages of development.

The software related to this standard is to appear shortly as an open-source
project on COIN-OR.  A draft report describing it can be found at
http://www.optimization-online.org/DB_HTML/2006/03/1353.html.

Bob Fourer
4er at iems.northwestern.edu


> -----Original Message-----
> From: coin-discuss-bounces at list.coin-or.org [mailto:coin-discuss-
> bounces at list.coin-or.org] On Behalf Of Michael Hennebry
> Sent: Thursday, April 27, 2006 1:51 PM
> To: Discussions about open source software for Operations Research
> Subject: Re: [Coin-discuss] Benchmark Instances & code for format
> conversions
> 
> On Thu, 27 Apr 2006, Tobias Achterberg wrote:
> 
> > Dear Anureet,
> 
> > > To summarize, availability of benchmark instances in "appropriate
> > > format" is an equally important aspect of computational OR as is the
> > > availability of the code. In my opinion, maintaining benchmark
> instances
> > > and "format conversion codes" along with the implementation code would
> > > greatly enhance the scope and reach of COIN-OR.
> >
> > I totally agree. But please keep in mind that this is a non-trivial
> > task. Just creating a website where everyone can upload instances is
> 
> More important than having an appropriate format
> is having a format that is well documented.
> 
> MPS is not necessarily an appropriate format.
> It won't work for nonlinear problems with
> a nonlinearity other than integrality.
> It's not good for TSPs.
> If one is testing a CTP solver,
> having it read a format that could represent
> any MILP would not seem to be a good idea.
> 
> > by far not enough. You will have to actively collect instances, make
> > sure that you give credit to the original source, if file format
> > conversion has to be applied you have to indicate this and give the
> > instance a different name, ....
> 
> Another possibility is to insist on really good format documentation.
> If the format defines a MILP, one could insist that
> the documentation include source for library functions that can
> read a file into a data structure and
> given the corresponding variable name or row name,
> return a representation of the exact value of any
> of the coefficients or bounds defining the MILP.
> The format of the exact representation should be defined by COIN-OR.
> 
> --
> Mike   hennebry at web.cs.ndsu.NoDak.edu
> "Demons after money?
> Whatever happened to the still-beating heart of a virgin?
> No one has any standards any more."                    --  Rupert Giles
> 
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