Context Navigation

NEWS @ 10:5545663ca997

subpack-glpk

Last change on this file since 10:5545663ca997 was 9:33de93886c88, checked in by Alpar Juttner <alpar@…>, 13 years ago
Import GLPK 4.47
File size: 71.6 KB

Rev	Line
[9]	1	GLPK 4.47 (release date: Sep 09, 2011)
	2
	3	The new API routine glp_intfeas1 was added to the package.
	4	This routine is a tentative implementation of the integer (0-1)
	5	feasibility solver based on the CNF-SAT solver (which currently
	6	is MiniSat). It may be used in the same way as glp_intopt to
	7	find either any integer feasible solution or a solution, for
	8	which the objective function is not worse than the specified
	9	value. Detailed description of this routine can be found in the
	10	document "CNF Satisfiability Problem", which is included in the
	11	distribution (see doc/cnfsat.pdf).
	12
	13	The following two options were added to glpsol:
	14
	15	--minisat translate 0-1 feasibility problem to CNF-SAT
	16	problem and solve it with glp_intfeas1/MiniSat
	17	(if the problem instance is already in CNF-SAT
	18	format, no translation is performed)
	19
	20	--objbnd bound add inequality obj <= bound (minimization) or
	21	obj >= bound (maximization) to 0-1 feasibility
	22	problem (this option assumes --minisat)
	23
	24	The paint-by-numbers puzzle model (pbn.mod) included in the
	25	distribution is a nice example of the 0-1 feasibility problem,
	26	which can be efficiently solved with glp_intfeas1/MiniSat. This
	27	model along with a brief instruction (pbn.pdf) and benchmark
	28	examples from <webpbn.com> encoded in GNU MathProg (*.dat) can
	29	be found in subdirectory examples/pbn/.
	30
	31	The glpsol lp/mip solver was modified to bypass postprocessing
	32	of MathProg models if the solution reported is neither optimal
	33	nor feasible.
	34
	35	A minor bug in examples/Makefile.am was fixed to correctly
	36	build glpk in a separate directory. Thanks to Marco Atzeri
	37	<marco.atzeri@gmail.com> for bug report and patch.
	38
	39	GLPK 4.46 (release date: Aug 09, 2011)
	40
	41	The following new API routines were added:
	42
	43	glp_read_cnfsat read CNF-SAT problem data in DIMACS format
	44	glp_check_cnfsat check for CNF-SAT problem instance
	45	glp_write_cnfsat write CNF-SAT problem data in DIMACS format
	46	glp_minisat1 solve CNF-SAT problem instance with MiniSat
	47
	48	The routine glp_minisat1 is a driver to MiniSat, a CNF-SAT
	49	solver developed by Niklas Een and Niklas Sorensson, Chalmers
	50	University of Technology, Sweden. This routine is similar to
	51	the routine glp_intopt, however, it is intended to solve a 0-1
	52	programming problem instance, which is the MIP translation of
	53	a CNF-SAT problem instance.
	54
	55	Detailed description of these new API routines can be found in
	56	the document "CNF Satisfiability Problem", which is included in
	57	the distribution (see files doc/cnfsat.tex and doc/cnfsat.pdf).
	58
	59	The following new glpsol command-line options were added:
	60
	61	--cnf filename read CNF-SAT problem instance in DIMACS
	62	format from filename and translate it to MIP
	63	--wcnf filename write CNF-SAT problem instance in DIMACS
	64	format to filename
	65	--minisat solve CNF-SAT problem instance with MiniSat
	66	solver
	67
	68	The zlib compression library (version 1.2.5) was ANSIfied,
	69	modified according to GLPK requirements and included in the
	70	distribution as an external software module. Thus, now this
	71	feature is platform independent.
	72
	73	Some bugs were fixed in the SQL table driver. Thanks to Xypron
	74	<xypron.glpk@gmx.de>.
	75
	76	GLPK 4.45 (release date: Dec 05, 2010)
	77
	78	This is a bug-fix release.
	79
	80	Several bugs/typos were fixed. Thanks to
	81	Xypron <xypron.glpk@gmx.de>,
	82	Robbie Morrison <robbie@actrix.co.nz>, and
	83	Ali Baharev <ali.baharev@gmail.com> for reports.
	84
	85	Some glpk documents was re-formatted and merged into a single
	86	document. Now the glpk documentation consists of the following
	87	three main documents (all included in the distribution):
	88
	89	GLPK: Reference Manual
	90
	91	GLPK: Graph and Network Routines
	92
	93	Modeling Language GNU MathProg: Language Reference
	94
	95	GLPK 4.44 (release date: Jun 03, 2010)
	96
	97	The following suffixes for variables and constraints were
	98	implemented in the MathProg language:
	99
	100	.lb (lower bound),
	101	.ub (upper bound),
	102	.status (status in the solution),
	103	.val (primal value), and
	104	.dual (dual value).
	105
	106	Thanks to Xypron <xypron.glpk@gmx.de> for draft implementation
	107	and testing.
	108
	109	Now the MathProg language allows comment records (marked by
	110	'#' in the very first position) in CSV data files read with the
	111	table statements. Note that the comment records may appear only
	112	in the beginning of a CSV data file.
	113
	114	The API routine glp_cpp to solve the Critical Path Problem was
	115	added and documented.
	116
	117	GLPK 4.43 (release date: Feb 20, 2010)
	118
	119	This is a maintainer release.
	120
	121	`configure.ac' was changed to allow building the package under
	122	Mac OS and Darwin with ODBC support.
	123	Thanks to Xypron <xypron.glpk@gmx.de> for suggestions and Noli
	124	Sicad <nsicad@gmail.com> for testing.
	125
	126	The SQL table driver was improved to process NULL data. Thanks
	127	to Xypron <xypron.glpk@gmx.de>.
	128
	129	Some bugs were fixed in the LP/MIP preprocessor.
	130
	131	GLPK 4.42 (release date: Jan 13, 2010)
	132
	133	The following new API routines were added:
	134
	135	glp_check_dup check for duplicate elements in sparse
	136	matrix
	137	glp_sort_matrix sort elements of the constraint matrix
	138	glp_read_prob read problem data in GLPK format
	139	glp_write_prob write problem data in GLPK format
	140	glp_analyze_bound analyze active bound of non-basic variable
	141	glp_analyze_coef analyze objective coefficient at basic
	142	variable
	143	glp_print_ranges print sensitivity analysis report (this
	144	routine replaces lpx_print_sens_bnds and
	145	makes it deprecated)
	146
	147	For description of these new routines and the GLPK LP/MIP
	148	format see a new edition of the reference manual included in
	149	the distribution. (Chapter "Graph and network API routines" was
	150	carried out from the main reference manual and included in the
	151	distribution as a separate document.)
	152
	153	The following new command-line options were added to the stand-
	154	alone solver glpsol:
	155	--glp filename read problem data in GLPK format
	156	--wglp filename write problem data in GLPK format
	157	--ranges filename print sensitivity analysis report (this
	158	option replaces --bounds)
	159
	160	Now all GLPK routines performing file I/O support special
	161	filenames "/dev/stdin", "/dev/stdout", and "/dev/stderr", which
	162	can be specified in the same way as regular filenames. This
	163	feature is plaform-independent.
	164
	165	GLPK 4.41 (release date: Dec 21, 2009)
	166
	167	The following new API routies were added:
	168
	169	glp_transform_row transform explicitly specified row
	170	glp_transform_col transform explicitly specified column
	171	glp_prim_rtest perform primal ratio test
	172	glp_dual_rtest perform dual ratio test
	173
	174	For description of these new routines see a new edition of the
	175	reference manual included in the distribution.
	176
	177	The following API routines are deprecated: lpx_transform_row,
	178	lpx_transform_col, lpx_prim_ratio_test, lpx_dual_ratio_test.
	179
	180	Some improvements were made in the MIP solver (glp_intopt).
	181
	182	The SQL table driver used to read/write data in MathProg models
	183	was changed to allow multiple arguments separated by semicolon
	184	in SQL statements. Thanks to Xypron <xypron.glpk@gmx.de>.
	185
	186	Two new options were added to the glpsol stand-alone solver:
	187	--seed value (to initialize the pseudo-random number generator
	188	used in MathProg models with specified value), and
	189	--ini filename (to use a basis previously saved with -w option
	190	as an initial basis on solving similar LP's).
	191
	192	Two new MathProg example models were included. Thanks to
	193	Nigel Galloway <nigel_galloway@operamail.com> and Noli Sicad
	194	<nsicad@gmail.com> for contribution.
	195
	196	Scripts to build GLPK with Microsoft Visual Studio 2010 for
	197	both 32-bit and 64-bit Windows were included. Thanks to Xypron
	198	<xypron.glpk@gmx.de> for contribution and testing.
	199
	200	GLPK 4.40 (release date: Nov 03, 2009)
	201
	202	The following new API routines were added:
	203
	204	glp_del_vertices remove vertices from graph
	205	glp_del_arc remove arc from graph
	206	glp_wclique_exact find maximum weight clique with the exact
	207	algorithm developed by Prof. P. Ostergard
	208	glp_read_ccdata read graph in DIMACS clique/coloring
	209	format
	210	glp_write_ccdata write graph in DIMACS clique/coloring
	211	format
	212
	213	For description of these new routines see a new edition of the
	214	reference manual included in the distribution.
	215
	216	The hybrid pseudocost branching heuristic was included in the
	217	MIP solver. It is available on API level (iocp.br_tech should
	218	be set to GLP_BR_PCH) and in the stand-alone solver glpsol
	219	(via the command-line option --pcost). This heuristic may be
	220	useful on solving hard MIP instances.
	221
	222	The branching heuristic by Driebeck and Tomlin (used in the
	223	MIP solver by default) was changed to switch to branching on
	224	most fractional variable if an lower bound of degradation of
	225	the objective is close to zero for all branching candidates.
	226
	227	A bug was fixed in the LP preprocessor (routine npp_empty_col).
	228	Thanks to Stefan Vigerske <stefan@math.hu-berlin.de> for the
	229	bug report.
	230
	231	A bug was fixed and some improvements were made in the FPUMP
	232	heuristic module. Thanks to Xypron <xypron.glpk@gmx.de>.
	233
	234	A bug was fixed in the API routine glp_warm_up (dual
	235	feasibility test was incorrect in maximization case). Thanks to
	236	Uday Venkatadri <Uday.Venkatadri@dal.ca> for the bug report.
	237
	238	GLPK 4.39 (release date: Jul 26, 2009)
	239
	240	The following new API routines were added:
	241
	242	glp_warm_up "warm up" LP basis
	243	glp_set_vertex_name assign (change) vertex name
	244	glp_create_v_index create vertex name index
	245	glp_find_vertex find vertex by its name
	246	glp_delete_v_index delete vertex name index
	247	glp_read_asnprob read assignment problem data in DIMACS
	248	format
	249	glp_write_asnprob write assignment problem data in DIMACS
	250	format
	251	glp_check_asnprob check correctness of assignment problem
	252	data
	253	glp_asnprob_lp convert assignment problem to LP
	254	glp_asnprob_okalg solve assignment problem with the
	255	out-of-kilter algorithm
	256	glp_asnprob_hall find bipartite matching of maxumum
	257	cardinality with Hall's algorithm
	258
	259	Also were added some API routines to read plain data files.
	260
	261	The API routines glp_read_lp and glp_write_lp to read/write
	262	files in CPLEX LP format were re-implemented. Now glp_write_lp
	263	correctly writes double-bounded (ranged) rows by introducing
	264	slack variables rather than by duplicating the rows.
	265
	266	For description of these new routines see a new edition of the
	267	reference manual included in the distribution.
	268
	269	The 'xfree(NULL)' bug was fixed in the AMD routines. Thanks to
	270	Niels Klitgord <niels@bu.edu> for bug report.
	271
	272	The message "Crashing..." was changed to "Constructing initial
	273	basis..." due to suggestion by Thomas Kahle <tom111@gmx.de>.
	274
	275	Some typos were corrected in glpsol output messages. Thanks to
	276	Xypron <xypron.glpk@gmx.de> for patch.
	277
	278	GLPK 4.38 (release date: May 02, 2009)
	279
	280	API routines glp_read_mps and glp_write_mps were improved.
	281
	282	Some improvements were made in the dual simplex routines.
	283
	284	Two external software modules AMD and COLAMD were included in
	285	the distribution (for more details please see src/amd/README
	286	and src/colamd/README). Now they are used in the interior-point
	287	solver to reorder the matrix prior to Cholesky factorization.
	288
	289	API routine glp_ipt_status may return two new statuses due to
	290	changes in the routine glp_interior. For details please see the
	291	reference manual included in the distribution.
	292
	293	A minor bug was fixed in the graph/network routines. Thanks to
	294	Nelson H. F. Beebe <beebe@math.utah.edu> for bug report.
	295
	296	GLPK 4.37 (release date: Mar 29, 2009)
	297
	298	The 0-1 Feasibility Pump heuristic was included in the GLPK
	299	integer optimizer glp_intopt. On API level the heuristic can be
	300	enabled by setting the parameter fp_heur in glp_iocp to GLP_ON.
	301	This feature is also available in the solver glpsol through
	302	command-line option '--fpump'. For more details please see the
	303	reference manual included in the distribution.
	304
	305	The following new API routines were added:
	306
	307	glp_print_sol write basic solution in printable format
	308	glp_print_ipt write interior-point solution in printable
	309	format
	310	glp_print_mip write MIP solution in printable format
	311	glp_read_graph read (di)graph from plain text file
	312	glp_write_graph write (di)graph to plain text file
	313	glp_weak_comp find all weakly connected components
	314	glp_strong_comp find all strongly connected components
	315
	316	The following API routines are deprecated: lpx_print_sol,
	317	lpx_print_ips, lpx_print_mip, lpx_print_prob (the latter is
	318	equivalent to glp_write_lp).
	319
	320	A bug was fixed in the interior-point solver (glp_interior) to
	321	correctly compute dual solution components when the problem is
	322	scaled.
	323
	324	The files configure.ac and Makefile.am were changed:
	325	(a) to allow using autoreconf/autoheader;
	326	(b) to allow building the package in a directory other than its
	327	source directory.
	328	Thanks to Marco Atzeri <marco_atzeri@yahoo.it> for bug report.
	329
	330	An example model in the GNU MathProg language was added.
	331	Thanks to Larry D'Agostino <Larry.D'Agostino@gmacrescap.com> for
	332	contribution.
	333
	334	GLPK 4.36 (release date: Feb 06, 2009)
	335
	336	The following new API routines were added to the package:
	337
	338	glp_mincost_okalg find minimum-cost flow with out-of-kilter
	339	algorithm
	340	glp_maxflow_ffalg find maximal flow with Ford-Fulkerson
	341	algorithm
	342
	343	For detailed description of these new routines and related data
	344	structures see chapter "Graph and Network API Routines" in a new
	345	edition of the reference manual included in the distribution.
	346
	347	The following two new command-line options were added to the
	348	solver glpsol:
	349
	350	--mincost read min-cost flow data in DIMACS format
	351	--maxflow read maximum flow data in DIMACS format
	352
	353	Duplicate symbols in the header glpk.h were removed to allow
	354	using swig.
	355	Thanks to Kelly Westbrooks <kellywestbrooks@yahoo.com> and
	356	Nigel Galloway <nigel_galloway@operamail.com> for suggestion.
	357
	358	A minor defect was fixed in the routine glp_write_lp.
	359	Thanks to Sebastien Briais <sbriais@free.fr> for bug report.
	360
	361	A minor bug was fixed in the SQL module.
	362	Thanks to Xypron <xypron.glpk@gmx.de> for patch.
	363
	364	Some new example models in the GNU MathProg modeling language
	365	were added. Thanks to Sebastian Nowozin <nowozin@gmail.com> and
	366	Nigel Galloway <nigel_galloway@operamail.com> for contribution.
	367
	368	GLPK 4.35 (release date: Jan 09, 2009)
	369
	370	The following new API routines were added to the package:
	371
	372	glp_create_graph create graph
	373	glp_set_graph_name assign (change) graph name
	374	glp_add_vertices add new vertices to graph
	375	glp_add_arc add new arc to graph
	376	glp_erase_graph erase graph content
	377	glp_delete_graph delete graph
	378	glp_read_mincost read minimum cost flow problem data in
	379	DIMACS format
	380	glp_write_mincost write minimum cost flow problem data in
	381	DIMACS format
	382	glp_mincost_lp convert minimum cost flow problem to LP
	383	glp_netgen Klingman's network problem generator
	384	glp_gridgen grid-like network problem generator
	385	glp_read_maxflow read maximum flow problem data in DIMACS
	386	format
	387	glp_write_maxflow write maximum flow problem data in DIMACS
	388	format
	389	glp_maxflow_lp convert maximum flow problem to LP
	390	glp_rmfgen Goldfarb's maximum flow problem generator
	391
	392	For detailed description of these new routines and related data
	393	structures see chapter "Graph and Network API Routines" in a new
	394	edition of the reference manual included in the distribution.
	395
	396	A minor change were made in the internal routine xputc. Thanks
	397	to Luiz Bettoni <bettoni@cpgei.ct.utfpr.edu.br> for suggestion.
	398
	399	A minor bug was fixed in the internal routine mpl_fn_time2str.
	400	Thanks to Stefan Vigerske <stefan@vigerske.de> for bug report.
	401
	402	GLPK 4.34 (release date: Dec 04, 2008)
	403
	404	The GNU MathProg modeling language was supplemented with three
	405	new built-in functions:
	406
	407	gmtime obtaining current calendar time
	408	str2time converting character string to calendar time
	409	time2str converting calendar time to character string
	410
	411	(Thanks to Xypron <xypron.glpk@gmx.de>.)
	412
	413	For detailed description of these functions see Appendix A in
	414	the document "Modeling Language GNU MathProg", a new edition of
	415	which was included in the distribution.
	416
	417	A bug was fixed in the MIP solver. Thanks to Nigel Galloway
	418	<nigel_galloway@operamail.com> for bug report.
	419
	420	A new makefile was added to build the GLPK DLL with Microsoft
	421	Visual Studio Express 2008 for 64-bit Windows. Thanks to Xypron
	422	<xypron.glpk@gmx.de> for contribution and testing.
	423
	424	GLPK 4.33 (release date: Oct 30, 2008)
	425
	426	The following new API routines were added to the package:
	427	glp_copy_prob copy problem object content
	428	glp_exact solve LP in exact arithmetic
	429	(makes lpx_exact deprecated)
	430	glp_get_unbnd_ray determine variable causing unboundedness
	431	(makes lpx_get_ray_info deprecated)
	432	glp_interior solve LP with interior-point method
	433	(makes lpx_interior deprecated)
	434
	435	The following new API routines for processing models written in
	436	the GNU Mathprog language were added to the package:
	437	glp_mpl_alloc_wksp allocate the translator workspace
	438	glp_mpl_read_model read and translate model section
	439	glp_mpl_read_data read and translate data section
	440	glp_mpl_generate generate the model
	441	glp_mpl_build_prob build LP/MIP instance from the model
	442	glp_mpl_postsolve postsolve the model
	443	glp_mpl_free_wksp deallocate the translator workspace
	444	(These routines make lpx_read_model deprecated.)
	445
	446	For description of all these new API routines see the reference
	447	manual included in the distribution.
	448
	449	A crude implementation of CPLEX-like interface to GLPK API was
	450	added to the package. Currently it allows using GLPK as a core
	451	LP solver for Concorde, a well known computer code for solving
	452	the symmetric TSP. For details see examples/cplex/README.
	453
	454	Some bugs were fixed in the SQL table driver. Thanks to Xypron
	455	<xypron.glpk@gmx.de>.
	456
	457	GLPK 4.32 (release date: Oct 03, 2008)
	458
	459	The following new features were included in the MIP solver
	460	(the API routine glp_intopt):
	461
	462	* MIP presolver
	463	* mixed cover cut generator
	464	* clique cut generator
	465	* Euclidean reduction of the objective value
	466
	467	Due to changes the routine glp_intopt may additionally return
	468	GLP_ENOPFS, GLP_ENODFS, and GLP_EMIPGAP.
	469
	470	The API routines lpx_integer are lpx_intopt are deprecated,
	471	since they are completely superseded by glp_intopt.
	472
	473	The following new branch-and-cut API routines were added:
	474	glp_ios_row_attr determine additional row attributes
	475	glp_ios_pool_size determine current size of the cut pool
	476	glp_ios_add_row add constraint to the cut pool
	477	glp_ios_del_row delete constraint from the cut pool
	478	glp_ios_clear_pool delete all constraints from the cut pool
	479
	480	For description of these new routines see the reference manual
	481	included in the distribution.
	482
	483	The stand-alone solver glpsol was changed to allow multiple
	484	data files.
	485
	486	A new edition of the supplement "Using Data Tables in the GNU
	487	MathProg Modeling Language" was included.
	488
	489	As usual, some bugs were fixed (in the MathProg translator).
	490	Thanks to Xypron <xypron.glpk@gmx.de>.
	491
	492	GLPK 4.31 (release date: Sep 02, 2008)
	493
	494	The core LP solver based on the dual simplex method was
	495	re-implemented and now it provides both phases I and II.
	496
	497	The following new API routines were added:
	498	glp_scale_prob automatic scaling of problem data
	499	glp_std_basis construct standard initial LP basis
	500	glp_adv_basis construct advanced initial LP basis
	501	glp_cpx_basis construct Bixby's initial LP basis
	502
	503	For description of these new routines see the reference manual
	504	included in the distribution.
	505
	506	The following API routines are deprecated:
	507	lpx_scale_prob, lpx_std_basis, lpx_adv_basis, lpx_cpx_basis.
	508
	509	Necessary changes were made in memory allocation routines to
	510	resolve portability issues for 64-bit platforms.
	511
	512	New version of the routine lpx_write_pb to write problem data
	513	in OPB (pseudo boolean format) was added to the package. Thanks
	514	to Oscar Gustafsson <oscarg@isy.liu.se> for the contribution.
	515
	516	Two new makefiles were added to build the package for 32- and
	517	64-bit Windows with Microsoft Visual Studio Express 2008.
	518	Thanks to Heinrich Schuchardt <heinrich.schuchardt@gmx.de> (aka
	519	Xypron) for the contribution and testing.
	520
	521	Two new makefiles were added to build the package with Digital
	522	Mars C/C++ 8.50 and Open Watcom C/C++ 1.6 (for 32-bit Windows).
	523
	524	GLPK 4.30 (release date: Aug 13, 2008)
	525
	526	The core LP solver based on the primal simplex method was
	527	re-implemented to allow its further improvements. Currently the
	528	new version provides the same features as the old one, however,
	529	it is a bit faster and more numerically stable.
	530
	531	Some changes were made in the MathProg translator to allow <,
	532	<=, >=, and > on comparing symbolic values. Thanks to Heinrich
	533	Schuchardt <heinrich.schuchardt@gmx.de> for patches.
	534
	535	Internal routine set_d_eps in the exact LP solver was changed
	536	to prevent approximation errors in case of integral data.
	537	Thanks to Markus Pilz <pilz@cs.uni-bonn.de> for bug report.
	538
	539	GLPK 4.29 (release date: Jul 06, 2008)
	540
	541	The configure script was changed to disable all optional
	542	features by default. For details please see file INSTALL.
	543
	544	The following new API routines were added:
	545	glp_erase_prob erase problem object content
	546	glp_read_mps read problem data in MPS format
	547	glp_write_mps write problem data in MPS format
	548	glp_read_lp read problem data in CPLEX LP format
	549	glp_write_lp write problem data in CPLEX LP format
	550
	551	For description of these new routines see the reference manual
	552	included in the distribution.
	553
	554	The following API routines are deprecated:
	555	lpx_read_mps, lpx_read_freemps, lpx_write_mps,
	556	lpx_write_freemps, lpx_read_cpxlp, and lpx_write_cpxlp.
	557
	558	Two bugs were fixed. Thanks to
	559	Anne-Laurence Putz <anne-laurence.putz@eurodecision.com> and
	560	Xypron <xypron.glpk@gmx.de> for bug report.
	561
	562	GLPK 4.28 (release date: Mar 25, 2008)
	563
	564	The iODBC and MySQL table drivers, which allows transmitting
	565	data between MathProg model objects and relational databases,
	566	were re-implemented to replace a static linking by a dynamic
	567	linking to corresponding shared libraries.
	568	Many thanks to Heinrich Schuchardt <heinrich.schuchardt@gmx.de>
	569	for the contribution, Rafael Laboissiere <rafael@debian.org>
	570	for useful advices concerning the shared library support under
	571	GNU/Linux, and Vijay Patil <vijay.patil@gmail.com> for testing
	572	this feature under Windows XP.
	573
	574	A new optional feature was added to the package. This feature
	575	is based on the zlib data compression library and allows GLPK
	576	API routines and the stand-alone solver to read and write
	577	compressed data files performing compression/decompression "on
	578	the fly" (compressed data files are recognized by suffix `.gz'
	579	in the file name). It may be useful in case of large MPS files
	580	to save the disk space (up to ten times).
	581
	582	The `configure' script was re-implemented. Now it supports the
	583	following specific options:
	584
	585	--with-gmp Enable using the GNU MP bignum library
	586	--without-gmp Disable using the GNU MP bignum library
	587	--with-zlib Enable using the zlib data compression
	588	library
	589	--without-zlib Disable using the zlib data compression
	590	library
	591	--enable-dl Enable shared library support (auto check)
	592	--enable-dl=ltdl Enable shared library support (GNU)
	593	--enable-dl=dlfcn Enable shared library support (POSIX)
	594	--disable-dl Disable shared library support
	595	--enable-odbc Enable using ODBC table driver
	596	--disable-odbc Disable using ODBC table driver
	597	--enable-mysql Enable using MySQL table driver
	598	--disable-mysql Disable using MySQL table driver
	599
	600	For more details please see file INSTALL.
	601
	602	GLPK 4.27 (release date: Mar 02, 2008)
	603
	604	Three new table drivers were added to the MathProg translator:
	605
	606	xBASE built-in table driver, which allows reading and writing
	607	data in .dbf format (only C and N fields are supported);
	608
	609	MySQL table driver, which provides connection to a MySQL
	610	database;
	611
	612	iODBC table driver, which provides connection to a database
	613	through ODBC.
	614
	615	The MySQL and iODBC table drivers were contributed to GLPK by
	616	Heinrich Schuchardt <heinrich.schuchardt@gmx.de>.
	617
	618	The table driver is a program module which allows transmitting
	619	data between MathProg model objects and external data tables.
	620
	621	For detailed description of the table statement and table
	622	drivers see the document "Using Data Tables in the GNU MathProg
	623	Modeling Language" (file doc/tables.txt) included in the
	624	distribution. Some examples which demonstrate using MySQL and
	625	iODBC table drivers can be found in subdirectory examples/sql.
	626
	627	GLPK 4.26 (release date: Feb 17, 2008)
	628
	629	The table statement was implemented in the GNU MathProg
	630	modeling language. This new feature allows reading data from
	631	external tables into model objects such as sets and parameters
	632	as well as writing results of computations to external tables.
	633
	634	A table is a (unordered) set of records, where each record
	635	consists of the same number of fields, and each field is
	636	provided with a unique symbolic name called the field name.
	637
	638	Currently the GLPK package has the only built-in table driver,
	639	which supports tables in the CSV (comma-separated values) file
	640	format. This format is very simple and supported by almost all
	641	spreadsheets and database management systems.
	642
	643	Detailed description of the table statement and CSV format can
	644	be found in file doc/tables.txt, included in the distribution.
	645
	646	GLPK 4.25 (release date: Dec 19, 2007)
	647
	648	A tentative implementation of Gomory's mixed integer cuts was
	649	included in the branch-and-cut solver. To enable generating
	650	Gomory's cuts the control parameter gmi_cuts passed to the
	651	routine glp_intopt should be set to GLP_ON. This feature is
	652	also available in the solver glpsol through command-line option
	653	'--gomory'. For more details please see the reference manual
	654	included in the distribution.
	655
	656	GLPK 4.24 (release date: Nov 21, 2007)
	657
	658	A tentative implementation of MIR (mixed integer rounding) cuts
	659	was included in the MIP solver. To enable generating MIR cuts
	660	the control parameter mir_cuts passed to the routine glp_intopt
	661	should be set to GLP_ON. This feature is also available in the
	662	stand-alone solver glpsol via command-line option '--mir'. For
	663	more details please see the reference manual included in the
	664	distribution.
	665
	666	The implementation is mainly based on the following two papers:
	667
	668	1. H. Marchand and L. A. Wolsey. Aggregation and mixed integer
	669	rounding to solve MIPs. CORE discussion paper 9839, CORE,
	670	Universite catholique de Louvain, June 1998.
	671
	672	2. G. Andreello, A. Caprara, and M. Fischetti. Embedding cuts
	673	in a Branch&Cut framework. Preliminary draft, October 2003.
	674
	675	MIR cuts can be generated on any level of the search tree that
	676	makes the GLPK MIP solver to be a real branch-and-cut solver.
	677
	678	A bug was fixed in the routine lpx_write_cpxlp. If a variable
	679	x has upper bound and no lower bound, it should appear in the
	680	bounds section as "-inf <= x <= u", not as "x <= u". Thanks to
	681	Enric Rodriguez <erodri@lsi.upc.edu> for the bug report.
	682
	683	GLPK 4.23 (release date: Oct 28, 2007)
	684
	685	The following new API routines were added:
	686
	687	glp_read_sol read basic solution from text file
	688	glp_write_sol write basic solution to text file
	689	glp_read_ipt read interior-point solution from text file
	690	glp_write_ipt write interior-point solution to text file
	691	glp_read_mip read MIP solution from text file
	692	glp_write_mip write MIP solution to text file
	693
	694	For description of these routines and corresponding file
	695	formats see Chapter "API Routines", Section "Utility routines"
	696	in the reference manual included in the distribution.
	697
	698	Advanced API routine glp_free_env was added. It may be used by
	699	the application program to free all resources allocated by GLPK
	700	routines.
	701
	702	The following three new command-line options were added to the
	703	solver glpsol:
	704
	705	--mipgap tol set relative MIP gap tolerance
	706	-r filename read solution from filename
	707	-w filename write solution to filename
	708
	709	GLPK 4.22 (release date: Sep 19, 2007)
	710
	711	This is a maintainer release.
	712
	713	A bug was fixed in the MIP preprocessor (ios_preprocess_node).
	714	Thanks to Roberto Bagnara <bagnara@cs.unipr.it> (Department of
	715	Mathematics, University of Parma, Italy) for the bug report.
	716
	717	A bug was fixed in the MIP preprocessor (col_implied_bounds),
	718	due to which constraint coefficients with small magnitude could
	719	lead to wrong implied bounds of structural variables.
	720
	721	A similar bug was fixed in the routine reduce_bounds.
	722
	723	A bug was fixed in the routines glp_set_mat_row and
	724	glp_set_mat_col. (The bug appeared due to incorrect removing
	725	zero elements from the row/column lists.)
	726
	727	A bug was fixed in the API routines lpx_read_mps and
	728	lpx_read_freemps, due to which bounds of type LI specified in
	729	BOUNDS section were incorrectly processed.
	730
	731	A call to standard function vsprintf was replaced by a call to
	732	vsnprintf for security reasons. Many thanks to Peter T. Breuer
	733	<ptb@inv.it.uc3m.es> and Rafael Laboissiere <rafael@debian.org>.
	734
	735	GLPK 4.21 (release date: Aug 28, 2007)
	736
	737	Additional reasons for calling the callback routine used in the
	738	MIP solver (glp_intopt) were introduced. Currently the following
	739	reasons are supported:
	740
	741	* request for subproblem selection
	742	* request for preprocessing
	743	* request for row generation
	744	* request for heuristic solution
	745	* request for cut generation
	746	* request for branching
	747	* better integer solution found
	748
	749	A basic preprocessing component used to improve subproblem
	750	formulations by tightening bounds of variables was included in
	751	the MIP solver. Depending on the control parameter pp_tech
	752	passed to the routine glp_intopt the preprocessing can be
	753	performed either on the root level or on all levels (default)
	754	or can be disabled.
	755
	756	Backtracking heuristic used by default in the MIP solver was
	757	changed to the "best local bound".
	758
	759	For more details see Chapter "Advanced API routines", Section
	760	"Branch-and-bound interface routines" in a new edition of the
	761	reference manual included in the distribution.
	762
	763	GLPK 4.20 (release date: Jul 26, 2007)
	764
	765	API routine lpx_integer was replaced by API routine glp_intopt,
	766	which provides equivalent functionality and additionally allows
	767	the application to control the solution process by means of the
	768	user-written callback routine, which is called by the solver at
	769	various points of the branch-and-bound algorithm. Besides, the
	770	new MIP solver allows generating "lazy" constraints and cutting
	771	planes on all levels of the branch-and-bound tree, not only on
	772	the root level. The routine lpx_integer is also still available
	773	for the backward compatibility.
	774
	775	The following new advanced API routines, which may be called
	776	from the B&B callback routine, were included in the package:
	777
	778	glp_ios_reason determine reason for calling callback
	779	routine
	780	glp_ios_get_prob access the problem object
	781	glp_ios_tree_size determine size of the branch-and-bound tree
	782	glp_ios_curr_node determine current active subproblem
	783	glp_ios_next_node determine next active subproblem
	784	glp_ios_prev_node determine previous active subproblem
	785	glp_ios_up_node determine parent subproblem
	786	glp_ios_node_level determine subproblem level
	787	glp_ios_node_bound determine subproblem local bound
	788	glp_ios_mip_gap compute relative MIP gap
	789	glp_ios_heur_sol provide solution found by heuristic
	790	glp_ios_terminate terminate the solution process
	791
	792	For description of these routines see Chapter "Advanced API
	793	routines", Section "Branch-and-bound interface routines" in a
	794	new edition of the reference manual, which was included in the
	795	distribution.
	796
	797	Old version of the integer optimization suite (IOS) as well as
	798	TSP solver tspsol based on it are no longer supported and were
	799	removed from the package.
	800
	801	A minor error in the MIP presolver was fixed; thanks to Graham
	802	Rockwell <bionomicron@gmail.com> for the bug report.
	803
	804	GLPK 4.19 (release date: Jul 05, 2007)
	805
	806	The principal change is upgrading to GPLv3.
	807
	808	A serious bug in the routine glp_del_cols was fixed; thanks to
	809	Cedric[FR] <fox2113@wanadoo.fr> for the bug report. The bug
	810	appeared because on deleting non-basic columns the basis header
	811	remained valid, however, contained invalid (old) column ordinal
	812	numbers.
	813
	814	A new advanced API routine glp_mem_limit was added.
	815
	816	The case GLP_EBOUND was added to the routine lpx_simplex.
	817	Thanks to Cameron Kellough <Cameron.Kellough@sri.com> for the
	818	bug report.
	819
	820	An API routine lpx_write_pb to write the problem instance in
	821	OPB (pseudo boolean) format format was added. Thanks to Oscar
	822	Gustafsson <oscarg@isy.liu.se> for the contribution.
	823
	824	Two new options --wpb and --wnpb were added to glpsol to write
	825	the problem instance in OPB format.
	826
	827	GLPK 4.18 (release date: Jun 25, 2007)
	828
	829	The following new API routines were added:
	830
	831	glp_set_rii set (change) row scale factor
	832	glp_set_sjj set (change) column scale factor
	833	glp_get_rii retrieve row scale factor
	834	glp_get_sjj retrieve column scale factor
	835	glp_simplex solve LP problem with the simplex method
	836	(this routine replaces lpx_simplex, which is
	837	also available for backward compatibility)
	838	glp_init_smcp initialize simplex method control params
	839	glp_bf_exists check if the basis factorization exists
	840	glp_factorize compute the basis factorization
	841	glp_bf_updated check if the basis factorization has been
	842	updated
	843	glp_get_bfcp retrieve basis factorization control params
	844	glp_set_bfcp change basis factorization control params
	845	glp_get_bhead retrieve the basis header information
	846	glp_get_row_bind retrieve row index in the basis header
	847	glp_get_col_bind retrieve column index in the basis header
	848	glp_ftran perform forward transformation
	849	glp_btran perform backward transformation
	850
	851	For description of all these routines see a new edition of the
	852	reference manual included in the distribution.
	853
	854	Type names ulong_t and uldiv_t were changed to glp_ulong and
	855	glp_uldiv to avoid conflicts with standard type names on some
	856	platforms. Thanks to Boris Wirtz <Boris.Wirtz@uni-oldenburg.de>
	857	for the bug report.
	858
	859	Some new examples in the MathProg language were added. Thanks
	860	to Sebastian Nowozin <nowozin@gmail.com>.
	861
	862	GLPK 4.17 (release date: May 26, 2007)
	863
	864	API routines glp_set_mat_row, glp_set_mat_col, and glp_load_mat
	865	were modified to allow zero constraint coefficients (which are
	866	not stored in the constraint matrix). Note that constraint
	867	coefficients with duplicate row/column indices are not allowed.
	868
	869	Another form of LP basis factorization was implemented in the
	870	package. It is based on LU-factorization of an initial basis
	871	and Schur complement to reflect changes in the basis. Currently
	872	the implementation is incomplete and provides only updating the
	873	factorization on replacing a column of the basis matrix. On API
	874	level the user can set the control parameter LPX_K_BFTYPE to
	875	choose between the folloiwng forms of LP basis factorization to
	876	be used in the simplex method routines:
	877	1) LU + Forrest-Tomlin update;
	878	2) LU + Schur complement + Bartels-Golub update;
	879	3) LU + Schur complement + Givens rotation update.
	880	The GLPK implementation is similar to LUSOL/LUMOD developed by
	881	Michael A. Saunders.
	882
	883	The user can choose the form of LP basis factorzation used by
	884	the simplex method routines by specifying the folloiwng options
	885	of glpsol: --luf, --cbg, --cgr.
	886
	887	GLPK 4.16 (release date: May 05, 2007)
	888
	889	A number of basic GLPK API routines, which now are in the
	890	stable stable, were renamed to be prefixed with 'glp_'. Note
	891	that all these routines are available via their old names
	892	prefixed with 'lpx_' that keeps the downward compatibility with
	893	older versions of the package.
	894
	895	Three new GLPK API routines were added to the package:
	896	glp_version, glp_term_hook, and glp_mem_usage; for more details
	897	see a new edition of the GLPK reference manual included in the
	898	distribution. The routine glp_version reports the actual version
	899	of the GLPK library and also can be used (along with the header
	900	glpk.h) in Autotools specification files to check if the GLPK
	901	library has been installed.
	902
	903	The header glpk.h was changed to conform to C++ environment.
	904
	905	GLPK 4.15 (release date: Feb 18, 2007)
	906
	907	Autotools specification files (configure.ac, Makefile.am) were
	908	changed to use GNU Libtool. This allows building the static as
	909	well as shared GLPK library.
	910
	911	GLPK 4.14 (release date: Feb 05, 2007)
	912
	913	Now GLPK conforms to ILP32, LLP64, and LP64 programming models
	914	(the latter seems to be the ultimate choice regarding 64-bit
	915	architectures). Note that GLPK itself is a 32-bit application,
	916	and the conformity only means that the package works correctly
	917	on all these arenae. Nevertheless, on 64-bit platforms it is
	918	possible to use more than 4GB of memory, if necessary.
	919
	920	GLPK 4.13 (release date: Nov 13, 2006)
	921
	922	A tentative implementation of the "exact" simplex method based
	923	on bignum (rational) arithmetic was included in the package.
	924
	925	On API level this new feature is available through the routine
	926	lpx_exact, which is similar to the routine lpx_simplex.
	927
	928	In the solver glpsol this feature is available through two new
	929	command-line options: --exact and --xcheck. If the '--exact'
	930	option is specified, glpsol solves LP instance using the exact
	931	simplex method; in case of MIP it is used to obtain optimal
	932	solution of LP relaxation. If the --xcheck option is specified,
	933	LP instance (or LP relaxation) is solved using the standard
	934	(floating-point) simplex method, however, then glpsol calls the
	935	exact simplex routine to make sure that the final LP basis is
	936	exactly optimal, and if it is not, to perform some additional
	937	simplex iterations in exact arithmetic.
	938
	939	GLPK 4.12 (release date: Nov 08, 2006)
	940
	941	A tentative implementation of some simplex method routines
	942	based on exact (bignum) arithmetic was included in the package.
	943	Currently these routines provide computing LU-factorization of
	944	the basis matrix and computing components of basic solution.
	945
	946	These routines were used to implement a routine, which checks
	947	primal and dual feasibility of basic solution exactly, i.e. in
	948	rational numbers, without round-off errors. In glpsol this
	949	feature is available through the command-line option --xcheck.
	950
	951	GLPK has its own low-level routines implementing operations on
	952	integer and rational numbers that makes it independent on other
	953	software packages. However, to attain a much better performance
	954	it is highly recommended to install (before configuring GLPK)
	955	the GNU Multiple Precision Arithmetic Library (GMP). Using GMP
	956	makes computations 100-200 times faster.
	957
	958	GLPK 4.11 (release date: Jul 25, 2006)
	959
	960	Three new built-in functions in the modeling language were
	961	implemented: card (cardinality of set), length (length of
	962	character string), and substr (substring of character string).
	963	Another improvement concerns the printf statement which now
	964	allows redirecting its output to a specified file. These new
	965	features are illustrated in example models crypto.mod and
	966	graph.mod included in the distribution. For more details see
	967	the document "Modeling Language GNU MathProg".
	968
	969	Four batch files (along with corresponding makefiles) were
	970	included in the distribution to simplify building GLPK under
	971	MS Windows; see them in subdirectory 'w32'.
	972
	973	GLPK 4.10 (release date: May 11, 2006)
	974
	975	Cutting planes of two new classes were implemented: mixed cover
	976	cuts and clique cuts. On API level this feature can be enabled
	977	by setting control parameter LPX_K_USECUTS passed to the routine
	978	lpx_intopt. In glpsol this feature is available through the
	979	command-line options --cover and --clique. For more details see
	980	the reference manual.
	981
	982	Now the routines lpx_read_mps and lpx_read_freemps support LI
	983	bound type. It is similar to LO, however, indicates the column
	984	as of integer kind.
	985
	986	GLPK 4.9 (release date: Jan 17, 2006)
	987
	988	An advanced MIP solver was implemented. It includes:
	989
	990	- basic presolving technique (removing free, singleton and
	991	redundant rows, improving bounds of columns, removing fixed
	992	columns, reducing constraint coefficents);
	993
	994	- generating cutting planes to improve LP relaxation (currently
	995	only Gomory's mixed integer cuts are implemented);
	996
	997	- using the branch-and-bound method to solve resultant MIP;
	998
	999	- recovering solution of the original MIP.
	1000
	1001	The solver is available on API level via the routine lpx_intopt
	1002	(see the reference manual). It is similar to the routine
	1003	lpx_integer, however, does not require initial solution of LP
	1004	relaxation.
	1005
	1006	The solver is also available in the command-line utility glpsol
	1007	via two options: --intopt (only presolving) and --cuts (assumes
	1008	--intopt plus generating cuts).
	1009
	1010	Note that efficiency of the MIP solver strongly depends on the
	1011	internal structure of the problem to be solved. For some hard
	1012	instances it is very efficient, but for other instances it may
	1013	be significantly worse than the standard branch-and-bound.
	1014
	1015	For some comparative benchmarks see doc/bench1.txt.
	1016
	1017	Well, what else...
	1018
	1019	Three built-in functions were added to MathProg: sin, cos, and
	1020	atan (the latter allows one or two arguments).
	1021
	1022	Some bugs were fixed.
	1023
	1024	Several new examples in MathProg were included: color.mod
	1025	(graph coloring problem), tsp.mod (traveling salesman problem),
	1026	and pbn.mod (paint-by-numbers puzzle).
	1027
	1028	GLPK 4.8 (release date: Jan 12, 2005)
	1029
	1030	Core simplex method and interior-point method routines were
	1031	re-implemented and now they use a new, "storage-by-rows" sparse
	1032	matrix format (unlike previous versions where linked lists were
	1033	used to represent sparse matrices). For details see ChangeLog.
	1034
	1035	Also a minor bug was fixed in API routine lpx_read_cpxlp.
	1036
	1037	GLPK 4.7 (release date: Aug 23, 2004)
	1038
	1039	Now GLPK supports free MPS format. Two new API routines
	1040	lpx_read_freemps (to read problem data in free MPS format) and
	1041	lpx_write_freemps (to write problem data in free MPS format)
	1042	were added. This feature is also available in the solver glpsol
	1043	via new command-line options --freemps and --wfreemps. For more
	1044	details see the GLPK reference manual.
	1045
	1046	API routines lpx_read_cpxlp and lpx_write_cpxlp for reading and
	1047	writing problem data in CPLEX LP format were re-implemented to
	1048	allow long symbolic names (up to 255 characters).
	1049
	1050	The following three modules were temporarily removed from the
	1051	GLPK distribution due to licensing problems: DELI (an interface
	1052	module to Delphi), GLPKMEX (an interface module to Matlab), and
	1053	JNI (an interface module to Java).
	1054
	1055	GLPK 4.6 (release date: Aug 04, 2004)
	1056
	1057	Three new statements were implemented in the GNU MathProg
	1058	language: solve, printf, and for. Their detailed description can
	1059	be found in the GLPK documentation included in the distribution.
	1060	(See also a sample model, examples/queens.mod, which illustrates
	1061	using these new statements.)
	1062
	1063	Two new API routines were added to the package: lpx_read_prob
	1064	and lpx_write_prob. They allow reading/writing problem data in
	1065	GNU LP low-level text format.
	1066
	1067	Three new command-line options were implemented in the LP/MIP
	1068	solver glpsol: --glp (to read problem data in GNU LP format),
	1069	--wglp (to write problem data in GNU LP format), and --name (to
	1070	change problem name). Now glpsol also supports processing models
	1071	where the new statements (see above) are used.
	1072
	1073	A new version of GLPKMEX, a Matlab MEX interface to GLPK, was
	1074	included. For more details see contrib/glpkmex/ChangeLog.
	1075
	1076	GLPK 4.5 (release date: Jul 19, 2004)
	1077
	1078	The branch-and-bound solver was completely re-implemented.
	1079
	1080	Some modifications were made in memory allocation routines that
	1081	allows using the package on 64-bit platforms.
	1082
	1083	For more details see ChangeLog.
	1084
	1085	GLPK 4.4 (release date: Jan 17, 2004)
	1086
	1087	All API routines were re-implemented using new data structures.
	1088	The new implementation provides the same specifications and
	1089	functionality of API routines as the old one, however, it has
	1090	some important advantages, in particular:
	1091	* linked lists are used everywhere that allows creating and
	1092	modifying the problem object as efficiently as possible
	1093	* all data stored in the problem object are non-scaled (even if
	1094	the internal scaling is used) that prevents distortion of the
	1095	original problem data
	1096	* solution components obtained by the solver remain available
	1097	even if the problem object has been modified
	1098	* no solver-specific data are used in the new data structures
	1099	that allows attaching any external lp/mip solver using GLPK
	1100	API as an uniform interface
	1101	Note that some API routines became obsolete being replaced by
	1102	new, more convenient routines. These obsolete routines are kept
	1103	for backward compatibility, however, they will be removed in
	1104	the future. For more details please see ChangeLog and the GLPK
	1105	Reference Manual.
	1106
	1107	New edition of the GLPK Reference Manual was included in the
	1108	distribution.
	1109
	1110	GLPKMEX, a Matlab MEX interface to GLPK package, contributed by
	1111	Nicolo Giorgetti <giorgetti@dii.unisi.it> was included in the
	1112	distribution.
	1113
	1114	GLPK FAQ contributed by Harley Mackenzie <hjm@bigpond.com> was
	1115	included in the distribution.
	1116
	1117	GLPK 4.3 (release date: Dec 12, 2003)
	1118
	1119	The bug, due to which the standard math library is not linked
	1120	on building the package on some platforms, was fixed.
	1121
	1122	The following new built-in functions were added to the MathProg
	1123	language: round, trunc, Irand224, Uniform01, Uniform, Normal01,
	1124	Normal. For details see the language description.
	1125
	1126	The MathProg syntax was changed to allow writing 'subj to' that
	1127	means 'subject to'.
	1128
	1129	The new api routine lpx_get_ray_info was added. It is intended
	1130	to determine which (non-basic) variable causes unboundness. For
	1131	details see the reference manual.
	1132
	1133	The module glpmps.c was changed to avoid compilation errors on
	1134	building the package on Mac OS X.
	1135
	1136	Several typos was fixed and some new material was added to the
	1137	GLPK documentation.
	1138
	1139	GLPK 4.2 (release date: Nov 14, 2003)
	1140
	1141	A preliminary implementation of the Integer Optimization Suite
	1142	(IOS) was included in the package. The Branch-and-Cut Framework
	1143	being completely superseded by IOS was removed from the package.
	1144
	1145	New API routine lpx_print_sens_bnds intended for bounds
	1146	sensitivity analysis was contributed to GLPK by Brady Hunsaker
	1147	<hunsaker@engr.pitt.edu>. This function is also available in
	1148	the solver glpsol (via command-line option --bounds).
	1149
	1150	An improved version of GLPK JNI (Java Native Interface) was
	1151	contributed by Chris Rosebrugh <cpr@pobox.com>.
	1152
	1153	GLPK DELI (Delphi Interface) was contributed by Ivo van Baren
	1154	<i.van.baren@freeler.nl>.
	1155
	1156	Several makefiles were added to allow compiling GLPK on some
	1157	non-GNU 32-bit platforms:
	1158	* Windows single-threaded static library, Visual C++ 6.0
	1159	* Windows multi-threaded dynamic library, Visual C++ 6.0
	1160	* Windows single-threaded static library, Borland C++ 5.2
	1161	* DOS single-threaded static library, Digital Mars C++ 7.50
	1162
	1163	And, of course, some bugs were fixed.
	1164
	1165	For more details see ChangeLog.
	1166
	1167	GLPK 4.1 (release date: Aug 23, 2003)
	1168
	1169	Some improvements were made in the lp/mip solver routines and
	1170	several bugs were fixed in the model translator.
	1171
	1172	For more details see ChangeLog.
	1173
	1174	GLPK 4.0 (release date: May 06, 2003)
	1175
	1176	Now GLPK supports the GNU MathProg modeling language, which is
	1177	a subset of the AMPL modeling language.
	1178
	1179	The document "GLPK: Modeling Language GNU MathProg" included in
	1180	the distribution is a complete description of GNU MathProg. (See
	1181	the files lang.latex, lang.dvi, and lang.ps in the subdirectory
	1182	'doc'. See also some examples in the subdirectory 'sample'.)
	1183
	1184	New version of the solver glpsol, which supports models written
	1185	in GNU MathProg, was implemented. (Brief instructions how to use
	1186	glpsol can be found in the GNU MathProg documentation.)
	1187
	1188	The GLPK/L modeling language is no more supported. The reason is
	1189	that GNU MathProg being much more powerful completely supersedes
	1190	all features of GLPK/L.
	1191
	1192	GLPK 3.3 (release date: Mar 25, 2003)
	1193
	1194	LP PRESOLVER
	1195	------------
	1196
	1197	Now the routine lpx_simplex (which is a driver to the simplex
	1198	method for solving LP) is provided with the built-in LP
	1199	presolver, which is a program that transforms the original LP
	1200	problem to an equivalent LP problem, which may be easier for
	1201	solving with the simplex method than the original one. Once the
	1202	transformed LP has been solver, the presolver transforms its
	1203	basic solution back to a corresponding basic solution of the
	1204	original problem. For details about this feature please see the
	1205	GLPK reference manual.
	1206
	1207	Currently the LP presolver implements the following features:
	1208	* removing empty rows;
	1209	* removing empty columns;
	1210	* removing free rows;
	1211	* removing fixed columns;
	1212	* removing row singletons, which have the form of equations;
	1213	* removing row singletons, which have the form of inequalities;
	1214	* removing column singletons, which are implied slack variables;
	1215	* fixing and removing column singletons, which are implied free
	1216	variables;
	1217	* removing forcing rows that involves fixing and removing the
	1218	corresponding columns;
	1219	* checking for primal and dual infeasibilities.
	1220
	1221	The LP presolver is also used by default in the stand-alone
	1222	program glpsol. In order not to use it, the option --nopresol
	1223	should be specified in the command-line.
	1224
	1225	CHANGES IN GLPK/L
	1226	-----------------
	1227
	1228	The syntax and semantics of the GLPK/L modeling language was
	1229	changed to allow declaration of "interval" sets. This means that
	1230	now the user can declare a set, for example, as:
	1231
	1232	set task = [8:11];
	1233
	1234	that is exactly equivalent to the following declaration:
	1235
	1236	set task = (task_8, task_9, task_10, task_11);
	1237
	1238	For details see the language description.
	1239
	1240	JAVA INTERFACE
	1241	--------------
	1242
	1243	Now GLPK includes the package GLPK JNI (Java Native Interface)
	1244	that implements Java binding for GLPK. It allows Java programs
	1245	to utilize GLPK in solving LP and MIP problems. For details see
	1246	a brief user's guide in the subdirectory contrib/java-binding.
	1247	This package was developed and programmed by Yuri Victorovich
	1248	<yuri@gjt.org>, who contributed it to GLPK.
	1249
	1250	GLPK 3.2.4 (release date: Feb 18, 2003)
	1251
	1252	This is a bug-fix release. For details see ChangeLog.
	1253
	1254	GLPK 3.2.3 (release date: Nov 11, 2002)
	1255
	1256	A new implementation of the api routine lpx_integer which now
	1257	is based on the b&b driver (which is based on the implicit
	1258	enumeration suite) was included in the package. This new
	1259	implementation has exactly the same functionality as the old
	1260	version, so all changes are transparent to the api user.
	1261
	1262	Four new api routines were included in the package:
	1263	lpx_check_kkt checks Karush-Kuhn-Tucker optmality conditions;
	1264	lpx_read_bas reads predifined basis in MPS format;
	1265	lpx_write_bas writes current basis in MPS format;
	1266	lpx_write_lpt writes problem data in CPLEX LP format.
	1267
	1268	Also other minor improvements were made (for details see the
	1269	file 'ChangeLog').
	1270
	1271	GLPK 3.2.2 (release date: Oct 14, 2002)
	1272
	1273	The api routine lpx_read_lpt was included in the package. It
	1274	is similar to the routine lpx_read_mps and intended to read
	1275	LP/MIP data prepared in CPLEX LP format. Description of this
	1276	format is given in the GLPK reference manual, a new edition of
	1277	which was also included in the distribution (see the files
	1278	'refman.latex', 'refman.dvi', 'refman.ps' in the subdirectory
	1279	'doc'). In order to use data files in CPLEX LP format with the
	1280	solver glpsol the option '--lpt' should be specified in the
	1281	command line.
	1282
	1283	Several bugs were fixed and some minor improvements were made
	1284	(for details see the file 'ChangeLog').
	1285
	1286	GLPK 3.2.1 (release date: Aug 12, 2002)
	1287
	1288	Now GLPK includes a preliminary implementation of the
	1289	branch-and-cut framework, which is a set of data structures and
	1290	routines intended for developing branch-and-cut methods for
	1291	solving mixed-integer and combinatorial optimization problems.
	1292
	1293	Detailed decsription of the branch-and-cut framework is given in
	1294	the document "GLPK: A Preliminary Implementation of the
	1295	Branch-And-Cut Framework" included in the distribution (see the
	1296	file 'brcut.txt' in the subdirectory 'doc').
	1297
	1298	In order to illustrate how the GLPK branch-and-cut framework
	1299	can be used for solving a particular optimization problem there
	1300	is an example included in the package. This is a stand-alone
	1301	program, TSPSOL, which is intended for solving to optimality the
	1302	symmetric Traveling Salesman Problem (TSP), a classical problem
	1303	of the combinatorial optimization (see the file 'tspsol.c' in
	1304	the subdirectory 'sample').
	1305
	1306	GLPK 3.2 (release date: Jul 15, 2002)
	1307
	1308	New edition of the document "GLPK: Reference Manual" was
	1309	included (see the files 'refman.latex', 'refman.dvi', and
	1310	'refman.ps' in the subdirectory 'doc').
	1311
	1312	New edition of the document "GLPK: Modeling Language GLPK/L" was
	1313	included (see the files 'lang.latex', 'lang.dvi', and 'lang.ps'
	1314	in the subdirectory 'doc').
	1315
	1316	The following new API routines were added to the package:
	1317
	1318	lpx_transform_row (transform explicitly specified row);
	1319	lpx_transform_col (transform explicitly specified column);
	1320	lpx_prim_ratio_test (perform primal ratio test);
	1321	lpx_dual_ratio_test (perform dual ratio test);
	1322	lpx_interior (solve LP problem using interior point method);
	1323	lpx_get_ips_stat (query status of interior point solution);
	1324	lpx_get_ips_row (obtain row interior point solution);
	1325	lpx_get_ips_col (obtain column interior point solution);
	1326	lpx_get_ips_obj (obtain interior point value of obj.func.);
	1327	lpx_read_lpm (read LP/MIP model written in GLPK/L);
	1328	lpx_write_mps (write problem data using MPS format);
	1329	lpx_print_ips (print interior point solution).
	1330
	1331	Detailed description of all these new API routines are given in
	1332	the new edition of the reference manual.
	1333
	1334	New version of the stand-alone solver glpsol (which is based on
	1335	the new API) was implemented.
	1336
	1337	So long as the new API (introduced in glpk 3.0) now provides
	1338	all the functions, which were provided by the old API, the old
	1339	API routines were removed from the package at all.
	1340
	1341	GLPK 3.1 (release date: May 27, 2002)
	1342
	1343	A preliminary implementation of new API routines was completed
	1344	and included in the package.
	1345
	1346	These new API routines provide much more flexible interaction
	1347	between the application program, LP/MIP problem instances, and
	1348	solver routines. Based on completely changed data structures
	1349	they are, however, similar to the API routines and provide the
	1350	same functionality. Please note that three routines, namely,
	1351	solving LPs using interior point method, reading model written
	1352	in the GLPK/L modeling language, and writing problem data in
	1353	the MPS format, are not implemented in the new API, however,
	1354	these routines are planned to be implemented in the next version
	1355	of the package.
	1356
	1357	A description of the new API routines is given in the document
	1358	"GLPK Reference Manual", a draft edition of which is included
	1359	in the package (see the files 'refman.latex', 'refman.dvi', and
	1360	'refman.ps' in the subdirectory 'doc').
	1361
	1362	Although the old API routines are kept in the package, they are
	1363	no longer supported and will be removed in the future.
	1364
	1365	GLPK 3.0.8 (release date: May 13, 2002)
	1366
	1367	A preliminary implementation of new API routines was included
	1368	in the package. These new API routines are intended to provide
	1369	much more flexible interaction between the application program,
	1370	LP/MIP problem and solver routines. See the document "New GLPK
	1371	API Routines" (the file 'newapi.txt' in the subdirectory 'doc')
	1372	also included in the package.
	1373
	1374	The api routines glp_simplex2, glp_call_ipm1, glp_call_bbm1 were
	1375	renamed, respectively, to glp_simplex, glp_interior, glp_integer
	1376	in order to reflect changes in implementation. The api routines
	1377	glp_call_rsm1, glp_simplex1, glp_pivot_in, glp_pivout_out were
	1378	removed from the package since they are completely supreseded by
	1379	the new API routines (however, these routines still can be found
	1380	in the subdirectory 'oldsrc'). Please consult a new edition of
	1381	the document "GLPK User's Guide" about all these changes in the
	1382	existing api routines.
	1383
	1384	The document "GLPK Library Reference" was removed from the
	1385	package (into the subdirectory 'oldsrc') since it describes the
	1386	obsolete library routines, most of which are no longer used.
	1387
	1388	GLPK 3.0.7 (release date: Apr 22, 2002)
	1389
	1390	A new, more efficient implementation of the primal/dual simplex
	1391	method was included in the package. Due to some improvements the
	1392	simplex-based solver allows solving many LP problems faster and
	1393	provides more reliable results. Note that the new implementation
	1394	is currently incomplete and available only via the api routine
	1395	glp_simplex2.
	1396
	1397	All the changes are transparent on API level.
	1398
	1399	GLPK 3.0.6 (release date: Mar 28, 2002)
	1400
	1401	New version of LU-factorization and basis maintenance routines
	1402	(based on Forrest-Tomlin updating technique) was implemented.
	1403	Since these new routines functionally supersede some routines
	1404	(which implement other forms of the basis matrix) and make them
	1405	obsolete, the latter were removed from the package (they still
	1406	can be found in the subdirectory 'oldsrc').
	1407
	1408	All the changes are transparent on API level.
	1409
	1410	GLPK 3.0.5 (release date: Jan 29, 2002)
	1411
	1412	New edition of the document "GLPK User's Guide" was included in
	1413	the distribution. Now it describes all additional API routines,
	1414	which were recently added to the package.
	1415
	1416	Structure of the package was re-organized in order to make its
	1417	maintenance easier (all small files in the subdurectory 'source'
	1418	were merged in bigger units). These changes are transparent for
	1419	the user.
	1420
	1421	GLPK 3.0.4 (release date: Dec 10, 2001)
	1422
	1423	A new, more efficient implementation of the two-phase primal
	1424	simplex method was included in the package. Due to some new
	1425	features (an advanced initial basis, projected steepest edge,
	1426	recursive updating values and reduced costs) the new LP solver
	1427	is faster and numerically more stable than the old one.
	1428
	1429	The new LP solver is available as API routine glp_simplex2 and
	1430	has the same purpose as API routine glp_call_rsm1. For detailed
	1431	specification see the file 'newapi.txt' in the directory 'doc'.
	1432
	1433	Now the new LP solver is also used by default to solve an
	1434	initial LP problem in the branch-and-bound routine glp_call_bbm1
	1435	instead the routine rsm1_driver. Note that the branch-and-bound
	1436	procedure itself is still based on rsm1_driver.
	1437
	1438	The new LP solver is also used as default solver in GLPSOL for
	1439	solving LP and MIP problems. In order to choose the old solver
	1440	the option '--old-sim' can be specified in the command line.
	1441
	1442	GLPK 3.0.3 (release date: Oct 03, 2001)
	1443
	1444	Some minor changes were made in the simplex method routines in
	1445	order to improve numerical stability of the method.
	1446
	1447	GLPK 3.0.2 (release date: Sep 24, 2001)
	1448
	1449	A new implementation of the basis maintaining routines was
	1450	included in the package. These routines, which are based on so
	1451	called FHV-factorization (a variety of LU-factorization) of the
	1452	basis matrix and Gustavson's data structures, allows performing
	1453	the main operations faster at the expense of some worsening
	1454	numerical accuracy.
	1455
	1456	AFI (Advanced Form of the Inverse), which is the form of the
	1457	basis matrix based on FHV-factorization, is available via the
	1458	parameter form = 3 (on API level) or via the option --afi (in
	1459	GLPSOL solver).
	1460
	1461	GLPK 3.0.1 (release date: Aug 01, 2001)
	1462
	1463	Old GLPK API routines have been removed from the package.
	1464
	1465	New GLPK API routines were added:
	1466
	1467	- scaling routines;
	1468
	1469	- a routine for writing problem data in MPS format;
	1470
	1471	- a comprehensive driver to the simplex method;
	1472
	1473	- basis maintaining routines.
	1474
	1475	A description of the new API routines is given in the document
	1476	"Additional GLPK API Routines". This document is included into
	1477	the distribution in plain text format (see the file 'newapi.txt'
	1478	in the subdirectory 'doc').
	1479
	1480	Now the distribution includes a non-trivial example of using
	1481	GLPK as a base LP solver for Concorde, a well known program that
	1482	solves Traveling Salesman Problem (TSP). For further details see
	1483	comments in the file 'sample/lpglpk30.c'.
	1484
	1485	GLPK 3.0 (release date: Jul 19, 2001)
	1486
	1487	Now GLPK is provided with new API, which being more flexible
	1488	can be used in more complex algorithmic schemes.
	1489
	1490	New edition of the document "GLPK User's Guide" is included in
	1491	the distribution. Now it completely corresponds to the new GLPK
	1492	API routines.
	1493
	1494	Old API routines are not removed yet from the package, however
	1495	they became obsolete and therefore should not be used. Since now
	1496	the header glpk.h corresponds to new API, in order to compile
	1497	existing programs that use old GLPK API routines the statement
	1498
	1499	#define GLP_OLD_API
	1500
	1501	should be inserted before the statement
	1502
	1503	#include "glpk.h"
	1504
	1505	GLPK 2.4.1 (release date: Jun 14, 2001)
	1506
	1507	The document "Modeling language GLPK/L" is included into the
	1508	distribution in texinfo format.
	1509
	1510	New edition of the document "GLPK User's Guide" is included in
	1511	the distribution. Now it describes all additional API routines
	1512	which were recently added to the package.
	1513
	1514	GLPK 2.4 (release date: May 10, 2001)
	1515
	1516	Now GLPK includes an implementation of a preliminary version
	1517	of the GLPK/L modeling language. This language is intended for
	1518	writing mathematcal programming models. The name GLPK/L is
	1519	derived from GNU Linear Programming Kit Language.
	1520
	1521	A brief description of the GLPK/L language is given in the
	1522	document "GLPK/L Modeling Language: A Brief Description". This
	1523	document is included into the distribution in plain text format
	1524	(see the file 'language.txt' in the subdirectory 'doc').
	1525
	1526	The language processor (which is a program that analyzes model
	1527	description written in GLPK/L and translates it to internal data
	1528	structures) is available as the GLPK API routine.
	1529
	1530	The stand-alone solver GLPSOL now is able: a) to process model
	1531	descriptions written in the GLPK/L language; b) to solve pure LP
	1532	problems using the interior point method (therefore the program
	1533	GLPIPM was removed from the package).
	1534
	1535	GLPK 2.3 (release date: Apr 09, 2001)
	1536
	1537	New edition of the document "GLPK User's Guide" is included in
	1538	the distribution. Now it describes all additional API routines
	1539	which were recently added to the package.
	1540
	1541	The MIP solver was fully re-programmed in order to improve its
	1542	robustness and performance. In particular, a basis recovering
	1543	procedure was implemented (this procedure allows switching to
	1544	the primal simplex method in case when the dual simplex method
	1545	fails).
	1546
	1547	GLPK 2.2 (release date: Mar 15, 2001)
	1548
	1549	Now GLPK includes a tentative implementation of the
	1550	branch-and-bound procedure based on the dual simplex method for
	1551	mixed integer linear programming (MIP).
	1552
	1553	Complete description of this new feature of the package is given
	1554	in the preliminary document "Mixed Integer Linear Programming
	1555	Using GLPK Version 2.2 (Supplement to GLPK User's Guide)". This
	1556	document is included into the distribution in plain text format
	1557	(see the file 'mip.txt' in the subdirectory 'doc').
	1558
	1559	The MIP solver (glp_integer) can be used as GLPK API routine in
	1560	the same way as the pure LP solver (glp_simplex).
	1561
	1562	The stand-alone program 'glpsol' is now able to solve LP as well
	1563	as MIP problems.
	1564
	1565	Note that the current version of GLPK MIP solver is based on
	1566	easiest heuristics for branching and backtrackng. Therefore the
	1567	solver is fit mainly for MIP problems which are not very hard
	1568	and have few integer variables.
	1569
	1570	GLPK 2.1 (release date: Feb 19, 2001)
	1571
	1572	The document "GLPK Implementation of the Revised Simplex Method"
	1573	is included into the distribution. This document describes most
	1574	of routines related to the revised simplex method.
	1575
	1576	GLPK 2.0 (release date: Jan 25, 2001)
	1577
	1578	Now GLPK includes a tentative implementation of the primal-dual
	1579	interior point method for large-scale linear programming.
	1580
	1581	The interior point solver can be used as GLPK API routine in the
	1582	same manner as the simplex method solver (glp_simplex):
	1583
	1584	ret = glp_interior();
	1585
	1586	Note that currently the interior point solver implemented in
	1587	GLPK doesn't include many important features, in particular:
	1588
	1589	* it can't process dense columns; therefore if the problem has
	1590	dense columns, the solving will be extremely inefficient;
	1591
	1592	* it has no special features against numerical unstability;
	1593	some problems may cause premature termination of the solving
	1594	when the matrix ADA' becomes ill-conditioned;
	1595
	1596	* it computes only values of primal (auxiliary and structural)
	1597	variables and doesn't compute values of dual variables (i.e.
	1598	reduced costs) which are just set to zero;
	1599
	1600	* it doesn't identify optimal basis corresponding to the found
	1601	interior point solution; all variables in the found solution
	1602	are just marked as basic variables.
	1603
	1604	GLPK also includes a stand-alone program 'glpipm' which is a
	1605	demo based on the interior point method. It may be used in the
	1606	same way as the program 'glpsol' that is based on the simplex
	1607	method.

Note: See TracBrowser for help on using the repository browser.

Download in other formats:

Original Format