-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 GLPK 4.24 -- Release Information ********************************
Release date: Nov 21, 2007 GLPK (GNU Linear Programming Kit) is intended for solving large-scale linear programming (LP), mixed integer linear programming (MIP), and other related problems. It is a set of routines written in ANSI C and organized as a callable library. In this release: A tentative implementation of MIR (mixed integer rounding) cuts was included in the MIP solver. To enable generating MIR cuts the control parameter mir_cuts passed to the routine glp_intopt should be set to GLP_ON. This feature is also available in the stand-alone solver glpsol via command-line option '--mir'. For more details please see the reference manual included in the distribution. The implementation is mainly based on the following two papers: 1. H. Marchand and L. A. Wolsey. Aggregation and mixed integer rounding to solve MIPs. CORE Report 9839, CORE, Universite catholique de Louvain, June 1998. 2. G. Andreello, A. Caprara, and M. Fischetti. Embedding cuts in a Branch&Cut framework. Preliminary draft, October 2003. MIR cuts can be generated on any level of the search tree that makes the GLPK MIP solver to be a real branch-and-cut solver. Using MIR cuts within the branch-and-cut solver allows solving some hard MIP instances, which are absolutely intractable for an ordinary branch-and-bound solver. (For example, the instances fiber, gesa2, gesa2_o, gesa3, gesa3_o, pp08a, pp08acut from MIPLIB, which are known to be hard, now can be solved by glpsol for less than a minute.) A bug was fixed in the routine lpx_write_cpxlp. If a variable x has upper bound and no lower bound, it should appear in the bounds section as "-inf <= x <= u", not as "x <= u". Thanks to Enric Rodriguez <[EMAIL PROTECTED]> for the bug report. See GLPK web page at <http://www.gnu.org/software/glpk/glpk.html>. GLPK distribution can be ftp'ed from <ftp://ftp.gnu.org/gnu/glpk/> or from some mirror ftp sites; see <http://www.gnu.org/order/ftp.html>. MD5 check-sum is the following: 765dcecc20dc6b80362e65c755f41976 *glpk-4.24.tar.gz GLPK is also available as a Debian GNU/Linux package. See its web page at <http://packages.debian.org/etch/glpk>. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (MingW32) iD8DBQFHRIbr0XvyMFmB6BgRAuE3AJ0Wx0eRbhbQolFxwsIrCGyQOWBQcwCgj3+5 3/gdgLyn2HiNvWJo4Pr7Wfc= =ukHG -----END PGP SIGNATURE----- _______________________________________________ GNU Announcement mailing list <info-gnu@gnu.org> http://lists.gnu.org/mailman/listinfo/info-gnu
