[Help-glpk] GLPK and the COIN-OR OSI interface

[Robbie Morrison]

Hello [help-glpk] list

First, some background.  As I understand it, COIN-OR
(COmputational INfrastructure for Operations Research)
is an IBM-sponsored initiative which combines open-source
solvers with a shared problem definition specification.
The idea is to enable solvers and problems to be readily
swapped.  The COIN-OR website is at: http://www.coin-or.org.

My guess is that the existing and future relationship
between GLPK and the COIN-OR project is a complex topic.

I want to ask about one aspect: the COIN-OR OSI (Open
Solver Interface) initiative.  OSI is intended to provide
a common interface layer for various Operations Research
problems, including LP and MILP.

I searched the [help-glpk] archive for information on OSI
and located an old posting, headed as follows:

   From:  Brady Hunsaker
   Subject:  Re: [Help-glpk] GLPK implementing OSI
   Date:  Mon, 19 Nov 2001 09:49:57 -0500

The current COIN-OR FAQ indicates that GLPK does support OSI:
http://www-124.ibm.com/developerworks/opensource/coin/faqs.html#OSI
That FAQ says:

Q. What is the OSI?
A. The Open Solver Interface (OSI) is a
   uniform API (Application Program Interface)
   for calling math programming solvers.
   Programs written to the OSI standard may be
   linked to any solver with an OSI interface
   and should produce correct results. The OSI
   has been significantly extended compared to
   its first incarnation. Currently, the OSI
   supports linear programming solvers (soon to
   be redesigned to support non-LP solvers) and
   has rudimentary support for integer
   programming. Among others the following
   operations are supported:

   * creating the LP formulation;
   * directly modifying the formulation by adding rows/columns;
   * modifying the formulation by adding cutting planes provided by CGL;
   * solving the formulation (and resolving after modifications);
   * extracting solution information;
   * invoking the underlying solver's branch-and-bound component.

   Programs in the CGL module are written to call
   the solver through the OSI.

Q: Which solvers currently work with OSI?
A: The following solvers currently have interfaces:

   * CLP
   * CPLEX
   * dylp
   * GLPK
   * OSL
   * SOPLEX
   * VOL
   * XPRESS-MP

I also searched the GLPK v4.5 documentation, but could find
no references to an OSI interface.

Could someone provide an update on this development please ??

many thanks in advance
Robbie Morrison
PhD student - model-supported energy policy
Technical University of Berlin, Germany
Victoria University of Wellington, New Zealand
---
Email (main) : address@hidden
Phone (home) : ++64.4.976 2343
[from Netscape IMAP client]