Tue Jul 25 12:00:00 2006 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.11 has been released.

        * include/glpbfi.h, src/glpbfi.c
        Basis factorization interface routines were added.

        * include/glpluf.h, src/glpluf1.c
        Hypersparse solution routines were added.

        * include/glpinv.h, src/glpinv1.c
        Hypersparse solution routines (fake version) were added.

        * include/glpmpl.h, src/glpmpl.c
        Built-in functions card, length, and substr were implemented.
        Output redirection in the printf statement was implemented.

        * examples/graph.mod, examples/crypto.mod
        Two example models illustrating new features of the modeling
        language were included.

Thu May 11 12:00:00 2006 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.10 has been released.

        * src/glplpx8a.c
        A fragment was added to the routines lpx_read_mps and
        lpx_read_freemps to accept LI bound type (it is similar to LO,
        however, additionally marks the column as integer).

        * include/glpbfi.h, src/glpbfi.c
        The module glpbfi which implements the basis factorization
        interface (BFI) was added.

        * src/glplpx7a.c
        The routine lpx_cover_cut to generate mixed cover cuts was
        added.

        * src/glplpx7b.c
        The routine lpx_clique_cut to generate clique cuts and related
        routines to maintain the conflict graph were added.

        * include/glplpx.h, src/glplpx5.c
        The routine lpx_cpx_basis implementing Bixby's algorithm to
        construct an initial LP basis was added.

        * examples/glpsol.c
        Command-line option '--bib' was added which allows building
        an initial LP basis using Bixby's algorithm.
        Default command-line option '--mps' was changed to '--freemps'.

        * examples/cf12a.mod, examples/cf12b.mod
        Two examples in MathProg (curve fitting problem) were added.
        Thanks to Dr. Harley Mackenzie <hjm@hardsoftware.com>.

Tue Jan 17 12:00:00 2006 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.9 has been released.

        * glpipp.h, glpipp1.c, glpipp2.c
        A MIP presolver were implemented (currently incomplete). It is
        used internally in the routine lpx_intopt (see below).

        * glplpx6d.c, glplpx7a.c
        An advanced branch-and-bound solver (the routine lpx_intopt)
        were implemented.

        * glplpx6c.c
        The routine lpx_check_int to check MIP feasibility conditions
        was added.

        * glplpx8a.c
        The routine lpx_print_mip was changed to print MIP feasibility
        conditions.

        * glpmpl.h, glpmpl1.c, glpmpl3.c
        The built-in functions sin, cos, atan, and atan2 were added to
        the MathProg language.

        * doc/lang.*
        Some typos were fixed.
        Thanks to Minh Ha Duong <haduong@centre-cired.fr> (CIRED, CNRS).

Wed Jan 12 12:00:00 2005 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.8 has been released.

        * glpspx.h, glpspx1.c, glpspx2.c, glplpx6a.c
        Simplex method routines were changed due to a new format of the
        constraint matrix.

        * glpmat.h, glpmat.c
        Sparse matrix routines were re-implemented using storage-by-rows
        format.

        * glpipm.h, glpipm.c, glplpx6b.c
        Interior-point method routines were changed due to a new format
        of sparse matrices.

        * glpchol.h, glpchol.c
        Old version of Cholesky factorization routines being replaced by
        a new one (see glpmat.c) was removed from the package.

        * glplpx8c.c
        Minor bug was fixed in api routine lpx_read_cpxlp.

Mon Aug 23 12:00:00 2004 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.7 has been released.

        * glplpx.h, glplpx1.c
        New core API routines were added (but not documented yet):
        lpx_order_matrix, lpx_create_index, lpx_find_row, lpx_find_col,
        lpx_delete_index.

        * glplpx8a.c
        API routine lpx_read_mps was re-implemented, and two new API
        routines lpx_read_freemps and lpx_write_freemps were added to
        support free MPS format.

        * glplpx8c.c
        Two API routines lpx_read_cpxlp and lpx_write_cpxlp (formerly
        named lpx_read_lpt and lpx_write_lpt) were re-implemented.

        * glpmps.h, glpmps.c
        This module formerly used in lpx_read_mps was removed from the
        package.

        * glplpt.h, glplpt.c
        This module formerly used in lpx_read_lpt was removed from the
        package.

        * glpmip.h, glpmip1.h, glpmip2.h
        New MIP routines mip_best_node and mip_relative_gap were added
        due to suggestion of Brady Hunsaker <hunsaker@engr.pitt.edu>.

        * glpsol.c
        The following new command-options were added:
        --freemps  to read problem data in free MPS format
        --wfreemps to write problem data in free MPS format
        --cpxlp    to read problem data in CPLEX LP format
        --wcpxlp   to write problem data in CPLEX LP format
        --bas      to read LP basis from a text file in MPS format
        --wbas     to write LP basis to a text file in MPS format
        --mostf    to use "most fractional" branching heuristic
        --bestb    to use "best bound" backtracking heuristic

        * contrib/deli/*.*
        GLPK Delphi interface module was temporarily removed from the
        distribution due to licensing problems.

        * contrib/glpkmex/*.*
        GLPK Matlab interface module was temporarily removed from the
        distribution due to licensing problems.

        * contrib/jni/*.*
        GLPK Java interface module was temporarily removed from the
        distribution due to licensing problems.

Wed Aug 04 12:00:00 2004 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.6 has been released.

        * glpmpl.h, glpmpl1.c, glpmpl2.c, glpmpl3.c, glpmpl4.c
        Three new statements were implemented in the GNU MathProg
        language: solve, printf, and for. Also some bugs were fixed.

        * glplpx.h, glplpx8e.c
        Two API routines were added: lpx_read_prob and lpx_write_prob,
        which allow reading and writing problem data in GNU LP format.

        * glpsol.c
        Three new command-line options were added: --glp (to read
        problem data in GNU LP format), --wglp (to write problem data
        in GNU LP format), and --name (to change problem name).

        * glprng.h, glprng.c
        A portable pseudo-random number generator was implemented as a
        separate module.

        * glplib4.c
        The old implementation of a pseudo-random number generator was
        removed from the package.

        * doc/lang.*, doc/refman.*
        New edition of the GLPK documentation was included.

        * contrib/glpkmex/*.*
        A new version of GLPKMEX was included in the distribution. For
        more details see contrib/glpkmex/ChangeLog.

Mon Jul 19 12:00:00 2004 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.5 has been released.

        * glpmip.h, glpmip1.c, glpmip2.c, glplpx6c.c
        New implementation of the branch-and-bound method was added.
        It replaces the old implementation, which was removed from the
        package.

        * glpies.h, glpies1.c, glpies2.c, glpies3.c
        Modules used in the old implementation of the branch-and-bound
        method were removed from the package.

        * glplib2.c
        Now if the preprocessor variable GLPHUGEMEM is defined, other
        version of the routines umalloc, ucalloc, and ufree is used on
        compiling the package. This allows avoiding memory allocation
        problems on platforms where sizeof(void *) > sizeof(int), for
        example, where addresses are 64-bit while integers are 32-bit.
        The modification was made due to a bug report provided by Karel
        Zimmermann <kzimm@diamant.jouy.inra.fr> and Christophe Caron
        <caron@diamant.jouy.inra.fr>.

Sat Jan 17 12:00:00 2004 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.4 has been released.

        * glplpx.h, glplpx*.c
        All API routines were re-implemented using new data structures.
        Some new API routines were added and some existing API routines
        became obsolete as shown below:

        Obsolete API routine   Equivalent new API routine
        lpx_check_name         (no more supported)
        lpx_set_obj_c0         lpx_set_obj_coef
        lpx_set_row_coef       (no more supported)
        lpx_set_col_coef       lpx_set_obj_coef
        lpx_load_mat           (no more supported)
        lpx_load_mat3          lpx_load_matrix
        lpx_unmark_all         (no more supported)
        lpx_mark_row           (no more supported)
        lpx_mark_col           (no more supported)
        lpx_clear_mat          (no more supported)
        lpx_del_items          lpx_del_rows, lpx_del_cols
        lpx_get_row_bnds       lpx_get_row_type, lpx_get_row_lb,
                               lpx_get_row_ub
        lpx_get_col_bnds       lpx_get_col_type, lpx_get_col_lb,
                               lpx_get_col_ub
        lpx_get_obj_c0         lpx_get_obj_coef
        lpx_get_row_coef       (no more supported)
        lpx_get_col_coef       lpx_get_obj_coef
        lpx_get_row_mark       (no more supported)
        lpx_get_col_mark       (no more supported)
        lpx_get_row_info       lpx_get_row_stat, lpx_get_row_prim,
                               lpx_get_row_dual
        lpx_get_col_info       lpx_get_col_stat, lpx_get_col_prim,
                               lpx_get_col_dual
        lpx_get_ips_stat       lpx_ipt_status
        lpx_get_ips_row        lpx_ipt_row_prim, lpx_ipt_row_dual
        lpx_get_ips_col        lpx_ipt_col_prim, lpx_ipt_col_dual
        lpx_get_ips_obj        lpx_ipt_obj_val
        lpx_get_mip_stat       lpx_mip_status
        lpx_get_mip_row        lpx_mip_row_val
        lpx_get_mip_col        lpx_mip_col_val
        lpx_get_mip_obj        lpx_mip_obj_val

        Obsolete API routines were kept for backward compatibility,
        however, they will be removed in the future.

        * doc/refman.*
        New edition of the GLPK reference manual containing description
        of all new API routines was included.

        * contrib/glpkmex/*.*
        GLPKMEX, a Matlab MEX interface to GLPK package, contributed by
        Nicolo Giorgetti <giorgetti@dii.unisi.it> was included.

        * doc/GLPK_FAQ.txt
        GLPK FAQ contributed by Harley Mackenzie <hjm@bigpond.com> was
        included.

Fri Dec 12 12:00:00 2003 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.3 has been released.

        * configure.in
        The bug, due to which the standard math library is not linked on
        some platforms, was fixed.

        * glpmpl3.c
        The bug (0 ** y) was fixed in the routine fp_power.

        * glpmpl.h, glpmpl1.c, glpmpl3.c
        Some new built-in functions (round, trunc, Irand224, Uniform01,
        Uniform, Normal01, Normal) were added to the MathProg language.

        * glpmpl1.c
        The MathProg syntax was changed to allow writing 'subj to'.

        * glplpx.h, glplpx1.c, glplpx2.c
        The new api routine lpx_get_ray_info was added.

        * glplpx8a.c
        The api routine lpx_print_sol was changed to print the number of
        non-basic variable, which causes primal unboundness.

        * glpmps.c
        The code was changed to avoid errors on compiling the package on
        Mac OS X. Thanks to Andre Girard <andre@inrs-emt.uquebec.ca> for
        the bug report.

        * doc/lang.*, doc/refman.*
        Several typos were fixed and some new material was added in the
        glpk documentation.
      
Fri Nov 14 12:00:00 2003 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.2 has been released.

        * glpiet.h, glpiet.c, glpios.h, glpios1.c, glpios2.c, glpios3.c
        A preliminary implementation of the Integer Optimization Suite
        (IOS) was included in the package. Eventually IOS will replace
        the Implicit Enumeration Suite (IES).

        * glplpx.h, glplpx6d.c
        A dummy version of the integer optimization routine lpx_intopt
        was included in the package. Later this routine will replace the
        routine lpx_integer.

        * examples/glpsol.c
        A new command-line option --int-opt was added to the solver to
        call lpx_intopt rather than lpx_integer.

        * glpbcs.h, glpbcs1.c, glpbcs2.c
        Being replaced by IOS routines (see above) the Branch-and-Cut
        Framework (BCS) routines were removed from the package.

        * examples/tspsol.c
        Stand-alone Symmetric TSP solver was completely re-programmed
        using IOS routines.

        * glplib.h, glplib2.c, glplib4.c
        The random-number generator was implemented. It is based on the
        module GB_FLIB from the Stanford GraphBase originally developed
        by Donald Knuth.

        * glphbsm.c, glplpx8a.c, glpmps.c
        All calls to fopen/fclose were replaced by corresponding calls
        to ufopen/ufclose due to bug reports provided by Morten Welinder
        <terra@gnu.org> and <jpark@sfwmd.gov>.

        * glpmps.c
        The code was made re-entrant.

        * glplpx8b.c
        API routine lpx_print_sens_bnds for bounds sensitivity analysis
        contributed by Brady Hunsaker <hunsaker@engr.pitt.edu> was added
        to the package. This feature is also available in glpsol via the
        command-line option --bounds.

        * contrib/jni/*.*
        New version of GLPK JNI (Java Native Interface) contributed by
        Chris Rosebrugh <cpr@pobox.com> was added to the package.

        * contrib/deli/*.*
        GLPK DELI (Delphi Interface) contributed by Ivo van Baren
        <i.van.baren@freeler.nl> was added to the package.

        * glplpx3.c
        Default method to scale the problem was changed to equilibration
        scaling (lp->scale = 1 in lpx_reset_parms).

        * glplpx6a.c
        Two minor (non-critical) typos were fixed due to report provided
        by Andrew Hamilton-Wright <andrewhw@ieee.org>.

        * glplpp2.c
        An untested case (line 941) had been tested due to bug report
        provided by Jiri Spitz <jiri.spitz@telecom.cz>.

        * w32bc5.mak, w32vc6.mak, w32vc6d.mak, d32dmc.mak
        Several makefiles were added to allow building GLPK library for
        some non-GNU 32-bit platforms.

Sat Aug 23 12:00:00 2003 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.1 has been released.

        * glpmpl1.c, glpmpl3.c
        Some bugs were fixed in the MathProg translator due to the bug
        reports provided by Giles Thompson <gwpt1@cus.cam.ac.uk>:
        conditional set expressions were incorrectly parsed;
        dimen attribute was not set by default when a set was used
        recursively in its own declaration;
        logical expressions ... in if ... then ... else ... did not
        work;
        displaying set expressions did not free memory allocated for
        temporary results.

        * glpmpl3.c (reduce_terms)
        Implementation of summation of linear forms over domain was
        improved to reduce complexity of that operation from O(n*n) to
        O(n*log n). The improvement was made due to a report provided
        by Sebastien de Menten <sdementen@hotmail.com>.

        * glplpx6a.c (line 1056), glpmip1.c (line 641)
        Two minor bugs were fixed due to the bug report provided by
        Kendall Demaree <kendal.demaree@verizon.net>.

        * glplpx.h, glplpx6a.c
        The method of one artificial variable implemented in the routine
        lpx_prim_art and used on the phase I in the glpk simplex solver
        has a serious defect: for some lp instances it erroneously
        reports that the problem has no primal feasible solution. This
        error appears when the column of the artificial variable, which
        enters the basis to make it primal feasible, has large
        constraint coefficients, that leads to small reduced costs of
        non-basic variables and premature termination of the search,
        i.e. to wrong conclusion that the problem has no primal feasible
        solution. To avoid this defect the routine lpx_prim_feas was
        included. It implements the method of implicit artifical
        variables (based on minimization of the sum of infeasibilities),
        which is a bit slower but much more robust. The routine
        lpx_prim_feas having the same functionality now is used instead
        the routine lpx_prim_art.

        * glpinv.h, glpinv.c
        The test used in the routine inv_update to detect low accuracy
        after updating LU-factorization of the basis matrix was replaced
        by a new, more robust test.

        * glplpx6c.c
        Selecting an active node to be solved next in the routine
        btrack_bestp was changed. Now, if any integer feasible solution
        has not been found yet, the routine chooses an active node which
        has the minimal sum of integer infeasibilities.

        * glpmip.h, glpmip1.c
        The additional flag int_obj was included in the structure
        MIPTREE used by the branch-and-bound. This flag is set in the
        routine mip_create_tree and used in the routine is_better. It
        means that the objective is integral, i.e. depends only on
        integer variables with integer objective coefficients. The test
        used in the routine check_integrality was also replaced by a
        new, more reasonable one.

        * glplpx1.c
        A minor bug was fixed in the routine lpx_check_name.

        * glpmpl.h, glpmpl4.c, glplpx8d.c
        The flag skip_data was added to the parameter list of the
        routine mpl_read_model. If this flag is set, the data section
        in the model file is ignored. Corresponding change was made in
        the routine lpx_read_model. Now, if both model and data files
        are specified, the data section in the model file is ignored.

        * glplpx8c.c
        A minor bug (wrong format used for writing free columns) in the
        routine lpx_write_lpt was fixed due to the bug report provided
        by Bernhard Schmidt <schmidt@math.uni-augsburg.de>

        * sample/glpsol.c
        The command-line parameter --tmlim, which allows limiting the
        solution time, was added.

        * doc/lang.*, doc/refman.*
        New edition of the GLPK documentation was included.

        * java-binding/*.*
        New version of the GLPK JNI (Java Native Interface) package was
        included in the distribution.

        * sample/lpglpk40.c
        A non-trivial example was added. It allows using GLPK as a base
        LP solver for Concorde, a program for solving Traveling Salesman
        Problem (TSP). For details see comments in lpglpk40.c.

        * sample/*.mod
        Some examples of LP and MIP models written in GNU MathProg were
        added.

Tue May 06 12:00:00 2003 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 4.0 has been released.

        * glpmpl.h, glpmpl1.c, glpmpl2.c, glpmpl3.c, glpmpl4.c
        The model translator for the GNU MathProg modeling language was
        implemented and included in the package.

        * glplpx.h, glplpx8d.c
        The api routine lpx_read_model, which is an interface to the
        MathProg translator, was included in the package.

        * glplpx.h, glplpx8a.c
        The api routine lpx_print_prob for writing LP/MIP problem data
        in plain text format was included in the package.

        * sample/glpsol.c
        New version of the GLPK stand-alone LP/MIP solver that supports
        the GNU MathProg modeling language was implemented.

        * doc/lang.latex, doc/lang.dvi, doc/lang.ps
        The document "GLPK: Modeling Language GNU MathProg" was included
        in the package.

        * doc/refman.latex, doc/refman.dvi, doc/refman.ps
        New edition of the GLPK Reference Manual was included in the
        package.

        * glplpx8c.c
        A bug in the api routine lpx_write_lpt was fixed. Due to that
        bug an addressing error occured in the routine if the objective
        function has the non-zero constant term.

        * glplan.h, glplan1.c, glplan2.c, glplan3.c, glplan4.c,
        * glplan5.c, glplan6.c, glplan7.c, glplan8.c, glplpx8b.c
        All modules of the translator for the GLPK/L modeling language
        were removed from the package, because GLPK/L being completely
        superseded by GNU MathProg is no more supported.

Tue Mar 25 12:00:00 2003 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.3 has been released.

        * glplpp.h, glplpp1.c, glplpp2.c
        An implementation of the built-in LP presolver was added to the
        package.

        * glplpx.h
        The flag presol was added to the structure LPX. This flag tells
        the lpx_simplex whether the built-in LP presolver should be used
        or not. By default this flag is off. Also three macros (namely
        LPX_E_NOPFS, LPX_E_NODFS, and LPX_K_PRESOL) that concern using
        the LP presolver were introduced.

        * glplpx3.c, glplpx6a.c
        These modules was changed to use the built-in LP presolver.

        * sample/glpsol.c
        Command line options --presol and --nopresol that concern using
        the LP presolver were added to the stand-alone LP/MIP solver.

        * glplan1.c
        This module was changed to allow declaring sets like A[1:10] in
        the models written in the GLPK/L modeling language.

        * doc/refman.latex, doc/lang.latex
        New editions of the documents "GLPK User's Guide" and "GLPK/L
        Modeling Language" were included in the distribution.

        * java-binding/*.*
        The package GLPK JNI (Java Native Interface) implementing Java
        binding for GLPK was included in the distribution. This package
        was developed and programmed by Yuri Victorovich <yuri@gjt.org>.

Tue Feb 18 12:00:00 2003 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.2.4 has been released.

        * glplpx6b.c
        The code was changed to allow auxiliary variables have non-zero
        objective coefficients.

        Also a minor bug was fixed (the constant term was not considered
        on displaying the objective function value).

        * sample/glpsol.c
        The code was changed to fix a bug (the command-line option 'bfs'
        was not recognized). The bug was fixed due to report provided by
        Olivier <odwl@skynet.be>.

        * glplpt.c
        The code was changed to fix a bug (binary variables were treated
        erroneously as integer ones).

        * glplpx6b.c
        The code was changed to fix a bug (variables that have no lower
        bounds were incorrectly processed on converting to the standard
        formulation). The bug was fixed due to report kindly provided by
        Kjell Eikland <kjell.eikland@broadpark.no>.

Mon Nov 11 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.2.3 has been released.

        * glpmip.h, glpmip1.c
        A preliminary implementation of the branch-and-bound driver
        based on the implicit enumeration suite (glpies) was added to
        the package. This module is not documented yet.

        * glplpx6c.c
        A new implementation of the api routine lpx_integer which now
        is based on the b&b driver (see glpmip above) was included in
        the package. This new implementation has exactly the same
        functionality as the old version and therefore all changes are
        transparent to the api user.

        * glpbbm.h, glpbbm.c
        * glprsm.h, glprsm1.c, glprsm2.c
        * glplp.h, glplp.c
        These modules were removed from the package, because they were
        used only in the old version of the routine lpx_integer, which
        was replaced by the new version (see glplpx6c above).

        * glplpx.h, glplpx6a.c
        The api routine lpx_check_kkt was included in the package and
        its description was added in the reference manual. This routine
        allows checking Karush-Kuhn-Tucker optimality conditions for an
        LP solution.

        * glplpx.h, glplpx8a.c
        Now the api routine lpx_print_sol also prints information about
        "solution quality" obtained via the api routine lpx_check_kkt.

        * glplpx.h, glplpx8a.c
        New api routines lpx_read_bas and lpx_write_bas were included
        in the package and documented. The routine lpx_write_bas allows
        writing a current basis from an LP object to a text file in the
        MPS format. The routine lpx_read_bas allows reading a basis
        prepared in the MPS format from a text file into an LP object.

        * glplpt.c
        The parsing routine which reads LP problem data prepared in the
        CPLEX LP format was modified to allow specifying lower bounds
        of variables also in the form 'variable >= lower bound' (in the
        bounds section). This modification was made due to a notice
        provided by Ivan Luzzi <iluzzi@libero.it>.

        * glplpx.h, glplpx8c.c
        The api routine lpx_write_lpt which allows writing LP problem
        data from an LP object to a text file using the CPLEX LP format
        was included in the package and documented.

        * glplpx.h, glplpx3.c
        The control parameter LPX_K_LPTORIG that affects the behavior
        of the api routine lpx_write_lpt was introduced.

        * glplan6.c
        The semantics of the language GLPK/L was changed to allow
        selection in case when not all mute letters of a predicate (the
        operand that follows the keyword 'where') are presented in a
        parameter (the operand that precedes the keyword 'where'), i.e.
        to allow writing something like this:
            y[j] := sum(i, x[i] where p[i,j]);
        The paragraph "Selection" in the langauge description (page 25)
        was also correspondingly changed. This change of the language
        semantics was undertaken due to a notice provided by Peter Lee
        <plee@kinggee.com.au>.

        * sample/hwd.lpm
        A nice example of LP model written in GLPK/L and contributed by
        Peter Lee <plee@kinggee.com.au> was included in the package.

        * glplpx6b.c
        The api routine lpx_interior was modified: a) to compute dual
        values for all structural as well as auxiliary variables; b) to
        allow specifying non-zero objective coefficients at auxiliary
        variables.

        * sample/glpsol.c
        Three new command-line options were added to the solver, which
        are: --plain, --orig, and --wrlpt.

Mon Oct 14 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.2.2 has been released.

        * glplpt.h, glplpt.c
        A module that reads LP/MIP problem data in CPLEX LP format was
        implemented.

        * glplpx8c.c
        An api routine lpx_read_lpt that reads LP/MIP problem data in
        CPLEX LP format was implemented.

        * sample/glpsol.c, sample/plan.lpt
        A new command-line option '--lpt' that allows reading LP/MIP
        problem data in CPLEX LP format was added to the solver.

        * doc/refman.latex, doc/refman.dvi, doc/refman.ps
        A new edition of the Reference Manual was included.

        * source/*.c
        Casting to (unsigned char) was added in some calls to the
        classification functions (isalpha, etc.). The bug was fixed due
        to report provided by Morten Welinder <terra@diku.dk>.

        * glplpx8a.c
        The local routine mps_numb used in the routine lpx_write_mps
        was modified to correctly format floating-point numbers that
        have two digits in the decimal exponent. The bug was fixed due
        to report provided by Vlahos Kiriakos <Kiriakos.Vlahos@gs.com>.

        * glplan.h, glplan1.c, ..., glplan8.c
        Several serious bugs were fixed in the language processor due
        to reports provided by <NORBERT.PIOTROWSKI@LHSYSTEMS.COM>:
        (a) a static search tree used to find sparse array elements was
        sometimes overwritten that caused the message 'assertion failed'
        to appear; the bug was fixed by creating separate search trees
        in parsing routines; (b) a variable declared using the
        predicate-controlled variable declaration statement had wrong
        order of domain sets, because the variable array was built as
        a copy of the predicate array; the bug was fixed by using the
        internal routine transpose that coordinates mute letters (and
        therefore domain sets) on copying sparse arrays; (c) sometimes
        assignment statements like x[#a,#b,#c] := ... was incorrectly
        processed; the bug was fixed by including an appropriate check
        into the internal routine assign_stmt.

        * glp_simplex.c
        An additional check to see if all lower bounds are not greater
        than corresponding upper bounds was included in the routine to
        prevent wrong results to appear. Such incorrectness sometimes
        was not detected, namely, when variables with such bounds were
        non-basic and never entered the basis.

        * glpspx1.c
        Maximal number of simplex iterations before reinversion was
        decreased from 100 to 50. This allowed to improve accuracy and,
        that is more important, to reduce the solution time for many
        serial lp problems approximately 1.5--2 times.

        * glpspx2.c
        A check to see if all elements in the column chosen to enter
        the basis are close to zero in the routine spx_prim_chuzr was
        temporarily removed because this check gave wrong conclusion in
        case when the corresponding non-basic variable had zero column
        in the constraint matrix. An analogous check to see if all
        elements in the row chosen to leave the basis are close to zero
        in the routine spx_dual_chuzc was also temporarily removed on
        the same reason. The bug was fixed due to reports provided by
        Flavio Keidi Miyazawa <fkm@ic.unicamp.br> and Vlahos Kiriakos
        <Kiriakos.Vlahos@gs.com>.

Mon Aug 12 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.2.1 has been released.

        * glpbcs.h, glpbcs1.c, glpbcs2.c
        * glpies.h, glpies1.c, glpies2.c, glpies3.c
        A preliminary implementation of the branch-and-cut framework
        was included in the package.

        * doc/brcut.txt
        The document "GLPK: A Preliminary Implementation of the
        Branch-And-Cut Framework" was included in the distribution.

        * sample/tspsol.c
        An illustrative program for solving symmetric TSP based on the
        branch-and-cut method was included in the package.

        * glpdmp.h, glpdmp.c
        A new, re-enterable version of routines for managing dynamic
        memory pools was included in the package.

        * glpavl.h, glpavl.c
        A new, re-enterable version of routines for managing AVL search
        trees was included in the package.

        * glplib.h, glplib2.c
        Two new low-level routines ufopen and ufclose were included in
        the package.

        * glplpx.h, glplpx7.c
        The following new api routines were added: lpx_eval_activity,
        lpx_eval_red_cost, lpx_reduce_form, lpx_mixed_gomory.

        * glptsp.h, glptsp.c
        A module for reading TSP data using TSPLIB format was included
        in the package.

Mon Jul 15 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.2 has been released.

        * glplpx.h, glplpx1.c, glplpx2.c
        The identifier 'class' (used as a member name in the structure
        LPX and as an argument name in the routine lpx_set_class) was
        changed to 'clss' in order to avoid conflicts with C++ reserved
        words.

        * glpk.h, glplpx.h, glplpx1.c, glplpx2.c, glplpx6a.c,
        * glplpx6b.c, glplpx6c.c, glplpx7.c, glplpx8.c
        The following new api routines were added: lpx_set_obj_name,
        lpx_get_obj_name, lpx_get_row_mark, lpx_get_col_mark,
        lpx_transform_row, lpx_transform_col, lpx_prim_ratio_test,
        lpx_dual_ratio_test, lpx_interior, lpx_get_ips_stat,
        lpx_get_ips_row, lpx_get_ips_col, lpx_get_ips_obj, lpx_read_lpm,
        lpx_write_mps, lpx_print_ips.

        * glpsol.c
        The solver was completely re-programmed using new api routines.

        * lang.latex, lang.dvi, lang.ps
        New edition of the document "GLPK: Modeling Language GLPK/L"
        was included in the distribution.

        * refman.latex, refman.dvi, refman.ps
        New edition of the document "GLPK: Reference Manual" (which
        contains descriptions of all new api routines) was included in
        the distribution.

        * glpapi.h, glpapi1.c, glpapi2.c, glpapi3.c, glpapi4.c
        These files (which contain old api routines) were removed from
        the package.

        * glpipm1.c, glpipm2.c
        The file glpipm1.c was renamed to glpipm.c. The file glpipm2.c
        was used only by old api routines and therefore was removed from
        the package.

        * language.texinfo
        Old version of the document "GLPK: Modeling Language GLPK/L" was
        removed from the distribution.

Mon May 27 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.1 has been released.

        * glplpx.h, glplpx1.c, glplpx2.c, glplpx3.c, glplpx4.c,
        * glplpx5.c, glplpx6.c, glplpx7.c, glplpx8.c
        A preliminary implementation of new API routines was completed.

        * refman.latex, refman.dvi, refman.ps
        A draft edition of the document "GLPK Reference Manual", which
        describes new API routines, was included.

        * glplib3.c
        A bug in measuring long time intervals was fixed up.

        * glprsm3.c
        This module contains some obsolete routines not longer used and
        therefore it was removed from the package (into the subdirectory
        'oldsrc').

        * glprsm.h
        Some declarations related to the module 'glprsm3.c' (see above)
        were removed.

        * guide.texinfo
        The document "GLPK User's Guide" describing old API routines was
        removed from the package (into the subdirectory 'oldsrc').

        * newapi.txt
        The document "New GLPK API Routines" was removed at all, because
        it is superseded by the new reference manual (see above).

Mon May 13 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.8 has been released.

        * glplpx.h, glplpx1.c, glplpx2.c, glplpx3.c, glplpx4.c,
        * glplpx5.c, glplpx6.c, glplpx7.c
        A preliminary (currently incomplete) implementation of new api
        routines was included.

        * sample/newsamp.c
        A sample program for the new api routines was included.

        * newapi.txt
        A draft of the document "New GLPK API Routines" was included.

        * glpapi2.c, glpapi5.c, glpapi6.c
        These modules (which contain the api routines glp_call_rsm1,
        glp_simplex1, glp_pivot_in, glp_pivot_out) were removed from the
        package (to the subdirectory 'oldsrc') since these routines are
        functionally superseded by the new api routines.

        * glpk.h, glpapi2.c, glpapi3.c, glpapi4.c
        The api routines glp_simplex2, glp_call_ipm1, glp_call_bbm1 were
        renamed to glp_simplex, glp_interior, glp_integer, respectively.

        * sample/glpsol.c
        Some command-line options (which got obsolete due to the recent
        changes in api) were excluded.

        * doc/guide.texinfo
        New edition of the document "GLPK User's Guide" was included in
        the distribution to reflect the changes in some api routines.

        * doc/libref.texinfo
        This document was removed from the package (to the subdirectory
        'oldsrc') since it describes the library routines, most of which
        got obsolete and no longer used.

        * Makefile.in
        A minor bug was fixed up due to bug report from Hans Schwengeler
        <Hans.Schwengeler@unibas.ch>.

Mon Apr 22 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.7 has been released.

        * glpduff.h, glpduff.c, glpspx.h, glpspx1.c, glpspx2.c,
        * glpapi7.c
        These modules were replaced by a new implementation of the
        simplex method and therefore they were removed from the package
        (however they still can be found in the subdirectory 'oldsrc').

        * glprsm1.c
        The routine crash_aa was replaced by a new implementation and
        therefore it was removed from the file 'glprsm1.c'.

        * glplpx.h, glplpx.c, glpspx.h, glpspx1.c, glpspx2.c, glpspx3.c,
        * glpspx4.c, glpapi7.c
        New (currently incomplete) implementation of the simplex method
        components was included in the package.

Thu Mar 28 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.6 has been released.

        * glpluf.h, glpluf.c, glpinv.h, glpinv.c
        New version of LU-factorization and basis maintenance routines
        (based on Forrest-Tomlin updating technique) was implemented.

        * glpeta.h, glpeta.c, glpfhv.h, glpfhv.c, glpgel.h, glpgel.c,
        * glppfi.h, glppfi.c, glprfi.h, glprfi.c
        These routines implement some other forms of the basis matrix.
        Now they became obsolete being functionally superseded by the
        new version of basis maintenance routines (see above) and were
        removed from the package (however they still can be found in the
        subdirectory 'oldsrc').

        * glpbbm.c, glprsm.h, glprsm1.h, glprsm2.h, glpspx.h, glpspx2.c,
        * glprsm2.c, glpsol.c
        Necessary changes were made in order to use the new version of
        basis maintenance routines.

Tue Jan 29 12:00:00 2002 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.5 has been released.
        Structure of the package was re-organized in order to simplify
        its maintenance.

        * doc/guide.texinfo
        New edition of the document "GLPK User's Guide" was included in
        the distribution. Now the document includes descriptions of some
        additional API routines recently added to the package.

        * doc/newapi.txt
        The document "Additional GLPK API Routines" was removed from the
        distribution, because the corresponding material was included in
        the user's guide (see above).

Mon Dec 10 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.4 has been released.

        * glpspx.h, glpspx1.c, glpspx2.c, glpapi/glp_simplex2.h
        A new, more efficient version of the two-phase primal simplex
        method was implemented (advanced initial basis, projected
        steepest edge, recursive computations of solution components).

        * glpapi/glp_call_bbm1.c
        Now LP relaxation can be solved either using rsm1_driver(), or
        using glp_simplex2(). The choice is controlled by the parameter
        'meth' (a member of struct bbm1).

        * sample/glpsol.c
        The new implementation of the simplex method is now used by
        default. The old version is available via --old-sim option.

        * glpmat/gm_scaling.c
        Now this routine displays only two lines: an initial "quality"
        and a final "quality".

        * glplp/prepro_lp.c
        Identifiers 'fmin' and 'fmax' renamed to 'f_min' and 'f_max' in
        order to avoid conflict with <math.h>. The bug was fixed due to
        report provided by Sami Farin <sfarin@ratol.fi>.

Wed Oct 03 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.3 has been released.

        * glprsm/harris_row.c, glprsm/harris_col.c
        The relative tolerance used on the first pass of the two-pass
        ratio test was replaced by the absolute tolerance.

        * glprsm/rsm_primal.c, glprsm/rsm_feas.c, glprsm/rsm_dual.c
        The absolute tolerance passed to the two-pass ratio test routine
        was decaresed (for both primal and dual simplex).

        These changes were made in order to improve numerical stability
        of the simplex method.

        * glprsm/glp_call_rsm1.c, glprsm/glp_call_bbm1.c,
        * glprsm/glp_simplex1, glprsm/glp_pivoting.c
        Default form of the inverse was changed from RFI to AFI.

Mon Sep 24 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.2 has been released.

        * glpfhv.h, glpfhv.c
        New version of the basis maintaining routines was implemented.
        These routines, which are based on so called FHV-factorization
        (a variety of LU-factorization) and Gustavson's data structures,
        perform the main operations on the basis matrix faster at the
        expense of some worsening numerical accuracy.

        * glprsm.h, glprsm/afi.c
        The routines, which implement AFI (Advanced Form of the
        Inverse) based on FHV-factorization, were added to the package.
        This new form is available via the parameter form = 3 (on API
        level) or via the option --afi (in GLPSOL solver).

        * EFI was renamed to PFI
        In order to correct terminology the acronym EFI (Elimination
        Form of the Inverse) was replaced by PFI (Product Form of the
        Inverse) everywhere in the source code and the documentation.

        * glpset/umalloc.c, glpset/ucalloc.c
        * glpset/get_atom.c, glpset/get_atomv.c
        These memory management routines were changed in order *not* to
        clear allocated memory blocks by binary zeros.

Wed Aug 01 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0.1 has been released.

        * glpapi/old_api.c, glplp/extract_lp.c, store_lpsol.c
        Old API routines were deleted from the package.

        * include/glpk.h, include/glpapi.h, include/glplp.h
        Specifications of old API routines and data structures were
        removed from the headers.

        * sample/glpsol.c
        New version of the stand-alone solver GLPSOL that now uses new
        API routines was implemented.

        * glpapi/glp_set_row_fctr.c, glpapi/glp_set_col_fctr.c,
        * glpapi/glp_get_row_fctr.c, glpapi/glp_get_col_fctr.c,
        * glpapi/glp_scale_prob.c
        Scaling routines were added.

        * glpapi/glp_write_mps.c
        The routine for writing problem data in MPS format was added.

        * glpapi/glp_simplex1.c
        Comprehensive driver to the simplex method was added.

        * glpapi/glp_pivoting.c
        The routines glp_pivot_in() and glp_pivot_out() intended for
        basis maintaining were added.

        * glprsm/create_rsm.c, glprsm/delete_rsm.c, glprsm/scale_rsm.c,
        * glprsm/build_basis.c
        Additional low level routines related to the simplex method
        were added.

        * glpk.h, glpapi.h, glprsm.h
        Additional specifications for new routines and data structures
        were added.

        * sample/lpglpk30.c
        A non-trivial example was added. It allows using GLPK as a base
        LP solver for Concorde, a program for solving Traveling Salesman
        Problem (TSP). For details see comments in 'lpglpk30.c'.

        * doc/newapi.txt
        The document "Additional GLPK API Routines" that describes some
        new API routines was included.

Thu Jul 19 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 3.0 has been released.

        Now GLPK is provided with new API, which is intended for using
        the package in more complex algorithmic schemes.

        * glpapi/old_api.c
        All routines related to old API were gathered in one file named
        'old_api.c'.

        * glpapi/*.c
        These routines that implement new API were added to the package.

        * include/glpk.h, include/glpapi.h
        Specifications of new API routines and data structures were
        added to these headers. Specifications of old API routines and
        data structures were locked by #ifdef GLP_OLD_API directive.

        * doc/guide.texinfo
        New edition of the document "GLPK User's Guide" that correspond
        to new API was included.

Thu Jun 14 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 2.4.1 has been released.

        * doc/glpk_ml.texinfo
        The new document "Modeling Language GLPK/L" was included.

        * doc/glpk_ug.texinfo
        New edition of the document "GLPK User's Guide" was included.

        * doc/language.txt
        The preliminary document "GLPK/L Modeling Language: A Brief
        description" was removed from the distribution, because it has
        been replaced by the new document "Modeling Language GLPK/L".

        * glplang/l_spar.c
        The routine comparison() was re-programmed in order to
        implement the relation operation as specified in the language
        description.

        * glpmip.h, glpmip/*.c
        The partition 'glpmip' was renamed to 'glpbbm'.

Thu May 10 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 2.4 has been released.

        Now GLPK includes an implementation of a preliminary version of
        the GLPK/L modeling language.

        * glplang.h, glplang/*.c
        The header 'glplang.h' and a set of routines that implements
        the GLPK/L language processor (the partition 'glplang') were
        added to the package.

        * doc/language.txt
        The document "GLPK/L Modeling Language: A Brief Description
        (Supplement to GLPK User's Guide)" in plain text format was
        included in the package (see the file 'language.txt' in the
        subdirectory 'doc' of the distribution).

        * ex/model1.lpm, ex/model2.lpm
        Two examples of model descriptions written in GLPK/L were added
        to the package.

        * sample/glpsol.c
        This program was modified in order: a) to allow processing
        model description written in GLPK/L; b) to allow solving pure
        LP problem using the interior point method.

        * sample/glpipm.c
        This program was removed from the package, because its function
        was passed to the GLPSOL solver.

        * Makefile.in
        This file was changed in order to install the GLPSOL solver
        executable.

Mon Apr 09 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 2.3 has been released.

        * glpmip.h, glpmip/*.c
        These routines (that implement the branch-and-bound method) were
        re-programmed in order to improve robustness of implementation.
        In particular, heuristic routines were carried out from the main
        driver routine.

        Additional GLPK API routines were documented.

        New edition of the document "GLPK User's Guide" was included in
        the package.

        The preliminary document "Mixed Integer Programming Using GLPK
        Version 2.2 (Supplement to GLPK User's Guide)" was removed from
        the package, because this material was included in GLPK User's
        Guide.

Thu Mar 15 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 2.2 has been released.

        Now GLPK includes a tentative implementation of the
        branch-and-bound procedure based on the dual simplex method for
        mixed integer linear programming (MIP).

        The preliminary document "Mixed Integer Programming Using GLPK
        Version 2.2 (Supplement to GLPK User's Guide)" was included into
        the package in plain text format (see the file 'mip.txt' in the
        subdirectory 'doc' of the distribution).

        * glpmip.h, glpmip/*.c, glpapi/glp_integer.c
        These routines (that implement the branch-and-bound method) were
        added to the package.

        * sample/glpsol.c
        This program was modified in order to allow solving LP and MIP
        problems.

        * glprsm/rsm_primal.c, glprsm/rsm_dual.c, glprsm/rsm_feas.c,
        * glprsm/rsm1_driver.c
        These routines (which are drivers to basic components of the
        revised simplex method) were added to the package.

Mon Feb 19 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 2.1 has been released.

        * glprsm.h, glprsm/*.c
        These routines (that implement components of the revised simplex
        method) were re-programmed and documented.

        The document "GLPK Implementation of the Revised Simplex Method"
        was included into the package.

Thu Jan 25 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 2.0 has been released.

        Now GLPK includes a tentative implementation of the primal-dual
        interior point method for large-scale linear programming (for
        more details see the file `NEWS' in the distribution). A number
        of routines related to the interior point method were added to
        the package.

        * insist.c
        The routine `insist' and the macro of the same name were
        introduced into the package in order to replace the standard
        macro `assert'. Some routines require the expression specified
        in the `assert' macro to be evaluated, but compiling the package
        with NDEBUG option prevents from that. This bug was fixed due to
        bug report provided by Peter A. Huegler <phuegler@bsco.com>.

        * Makefile.in
        Minor bug was fixed due to a patch provided by Alexandre Oliva
        <oliva@lsd.ic.unicamp.br>.

Wed Jan 10 12:00:00 2001 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 1.1.2 has been released.

        * umalloc.c, ufree.c, create_pool.c, get_atom.c, get_atomv.c
        These routines were changed in order to fix a bug due to
        report provided by Andrew Hood <ajhood@fl.net.au>. Because of
        this bug data alignment error occured on the Sparc computer.

Tue Dec 14 12:00:00 2000 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 1.1.1 has been released.

        Minor bug was fixed in `Makefile.in'.

        GLPK Library Reference was included.

Mon Nov 27 12:00:00 2000 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 1.1 has been released.

        Minor changes were made in order to co-ordinate GLPK routines
        and their descriptions.

        GLPK User's Guide was included.

Fri Oct 20 12:00:00 2000 Andrew Makhorin <mao@mai2.rcnet.ru>

        * GLPK 1.0 has been released.