[Help-glpk] Re: Special Ordered Sets and extended MPS file formats

[Andrew Makhorin]

>I've been using GLPK for a few months now and it's really a great 
>software.

Thank you for your interest in glpk.

>I would like to suggest two enhancements :
>
>Even if GLPK seems not able to use special ordered sets information, it 
>would be nice if it did not choke on CPLEX LP format problem files that 
>provide it. The same remark applies to the MPS extensions used by CPLEX 
>(SOS & co.) and XPRESS (SETS).

Could you please provide me with an url to obtain a more complete
description of cplex lp format (or, if it's possible, send me such a
description via e-mail)? The document I used contains no information
about sos (it seems to be obsolete and of doubtful origin).

>Another improvement would be for GLPK to be able to read extended MPS 
>files as used by the two solvers previously mentioned, which have less 
>limitations about variables name lengths, and provides optimisation 
>sense information.

Which extended mps format do you mean? That one, which was introduced
in osl? Probably it would be useful to implement it, however, I've never
met real models coded in that format. Do you know any publically
available collections of lp/mip coded in that format (like netlib and
miplib)?

Andrew Makhorin