[Help-glpk] glpk 4.20 release information

[Andrew Makhorin]

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GLPK 4.20 -- Release Information
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Release date: Jul 26, 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:

API routine lpx_integer was replaced by new API routine glp_intopt,
which provides equivalent functionality and additionally allows the
application to control the solution process by means of the user-written
callback routine, which is called by the solver at various points of the
branch-and-bound algorithm. Besides, the new MIP solver allows
generating "lazy" constraints and cutting planes on all levels of the
branch-and-bound tree, not only on the root level. The routine
lpx_integer is also still available for the backward compatibility.

The following new advanced API routines, which may be called from the
callback routine, were included in the package:

glp_ios_reason     determine reason for calling callback routine
glp_ios_get_prob   access the problem object
glp_ios_tree_size  determine size of the branch-and-bound tree
glp_ios_curr_node  determine current active subproblem
glp_ios_next_node  determine next active subproblem
glp_ios_prev_node  determine previous active subproblem
glp_ios_up_node    determine parent subproblem
glp_ios_node_level determine subproblem level
glp_ios_node_bound determine subproblem local bound
glp_ios_mip_gap    compute relative MIP gap
glp_ios_heur_sol   provide solution found by heuristic
glp_ios_terminate  terminate the solution process

For description of these routines see Chapter "Advanced API routines",
Section "Branch-and-bound interface routines" in a new edition of the
reference manual, which was included in the distribution.

Old version of the integer optimization suite (IOS) as well as TSP
solver tspsol based on it are no longer supported and were removed from
the package.

A minor error in the MIP presolver was fixed; thanks to Graham Rockwell
<address@hidden> 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:

6dd68d9eef35c524489f3e935a0dae34 *glpk-4.20.tar.gz

GLPK is also available as a Debian GNU/Linux package. See its web page
at <http://packages.debian.org/stable/math/glpk.html>.
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