Log message:
Changes 4.32:

The following new features were included in the MIP solver
*  MIP presolver
*  mixed cover cut generator
*  clique cut generator
*  Euclidean reduction of the objective value

Due to changes the routine glp_intopt may additionally return
GLP_ENOPFS, GLP_ENODFS, and GLP_EMIPGAP.

The API routines lpx_integer are lpx_intopt are deprecated,
since they are completely superseded by glp_intopt.

The following new branch-and-cut API routines were added:
glp_ios_row_attr      determine additional row attributes
glp_ios_pool_size     determine current size of the cut pool
glp_ios_add_row       add constraint to the cut pool
glp_ios_del_row       delete constraint from the cut pool
glp_ios_clear_pool    delete all constraints from the cut pool

Log message:
Changes 4.31:
* The core LP solver based on the dual simplex method was
  re-implemented and now it provides both phases I and II.

* New API routines.

* For description of these new routines see the reference manual
  included in the distribution.

* The following API routines are deprecated:
  lpx_scale_prob, lpx_std_basis, lpx_adv_basis, lpx_cpx_basis.

* Necessary changes were made in memory allocation routines to
  resolve portability issues for 64-bit platforms.

* New version of the routine lpx_write_pb to write problem data
  in OPB (pseudo boolean format) was added to the package.

* Two new makefiles were added to build the package for 32- and
  64-bit Windows with Microsoft Visual Studio Express 2008.

* Two new makefiles were added to build the package with Digital
  Mars C/C++ 8.50 and Open Watcom C/C++ 1.6 (for 32-bit Windows).

Log message:
Changes 4.30:

* glpspx.h, glpspx03.c, glpapi06.c
  The primal simplex solver (spx_prim_opt, spx_prim_feas) was
  replaced by a new implementation (spx_primal), which currently
  provides the same features as the old version.

* glpmpl01.c, glpmpl03.c
  Some changes were made in the MathProg translator to allow <,
  <=, >=, and > on comparing symbolic values.

* glplpx10.c
  Internal routine set_d_eps in the exact LP solver was changed
  to prevent approximation errors in case of integral data.

Log message:
Add DESTDIR support.

Log message:
Changes 4.28:

The iODBC and MySQL table drivers, which allows transmitting
data between MathProg model objects and relational databases,
were re-implemented to replace a static linking by a dynamic
linking to corresponding shared libraries.
Many thanks to Heinrich Schuchardt <heinrich.schuchardt@gmx.de>
for the contribution, Rafael Laboissiere <rafael@debian.org>
for useful advices concerning the shared library support under
GNU/Linux, and Vijay Patil <vijay.patil@gmail.com> for testing
this feature under Windows XP.

A new optional feature was added to the package. This feature
is based on the zlib data compression library and allows GLPK
API routines and the stand-alone solver to read and write
compressed data files performing compression/decompression "on
the fly" (compressed data files are recognized by suffix `.gz'
in the file name). It may be useful in case of large MPS files
to save the disk space (up to ten times).

Log message:
Changes 4.25:
A tentative implementation of Gomory's mixed integer cuts was
included in the branch-and-cut solver. To enable generating
Gomory's cuts the control parameter gmi_cuts passed to the
routine glp_intopt should be set to GLP_ON. This feature is
also available in the solver glpsol through command-line option
'--gomory'. For more details please see the reference manual
included in the distribution.

Log message:
Changes 4.24:
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 discussion paper 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.

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 <erodri@lsi.upc.edu> for the bug report.

Log message:
Changes 4.23:
The following new API routines were added:
glp_read_sol    read basic solution from text file
glp_write_sol   write basic solution to text file
glp_read_ipt    read interior-point solution from text file
glp_write_ipt   write interior-point solution to text file
glp_read_mip    read MIP solution from text file
glp_write_mip   write MIP solution to text file

Log message:
Changes 4.22:
* Bug fixes

Log message:
Changes 4.18:
  The following new API routines were added:
  glp_set_rii        set (change) row scale factor
  glp_set_sjj        set (change) column scale factor
  glp_get_rii        retrieve row scale factor
  glp_get_sjj        retrieve column scale factor
  glp_simplex        solve LP problem with the simplex method
                     (this routine replaces lpx_simplex, which is
                      also available for backward compatibility)
  glp_init_smcp      initialize simplex method control params
  glp_bf_exists      check if the basis factorization exists
  glp_factorize      compute the basis factorization
  glp_bf_updated     check if the basis factorization has been
                     updated
  glp_get_bfcp       retrieve basis factorization control params
  glp_set_bfcp       change basis factorization control params
  glp_get_bhead      retrieve the basis header information
  glp_get_row_bind   retrieve row index in the basis header
  glp_get_col_bind   retrieve column index in the basis header
  glp_ftran          perform forward transformation
  glp_btran          perform backward transformation