source: releases/2.9.5/README.md @ 2197

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1# CBC Version 2.9.5 README
2
3Welcome to the README for the COIN Branch and Cut Solver (CBC). CBC is
4distributed under the Eclipse Public License and is freely redistributable.
5All source code and documentation is Copyright IBM and others. This README may
6be redistributed freely.
7
8## DOCUMENTATION
9
10For a quick start guide, please see the INSTALL file in this distribution. A
11(somehwat outdated) user's manual is available here:
12
13http://www.coin-or.org/Cbc
14
15More up-to-date automatically generated documentation of the source code can
16be found here:
17
18http://www.coin-or.org/Doxygen/Cbc/
19
20Further information can be found here:
21
22http://projects.coin-or.org/Cbc
23
24## SUPPORT
25
26### List Serve
27
28CBC users should use the Cbc mailing list. To subscribe, go to
29http://list.coin-or.org/mailman/listinfo/cbc
30
31### Bug Reports
32
33Bug reports should be reported on the CBC development web site at
34
35https://projects.coin-or.org/Cbc/newticket
36
37## CHANGELOG
38
39 * Release 2.9.5
40
41   * Bug fixes
42
43 * Release 2.9.4
44
45   * Small fixes for stability
46   * Fixes for Doygen documentation generation
47
48 * Release 2.9.3
49
50   * Minor bug fixes
51
52 * Release 2.9.2
53
54   * Fix for proper installation with ```DESTDIR```
55
56 * Release 2.9.1
57
58   * Fix for dependency linking
59   * Minor bug fixes
60
61 * Release 2.9.0
62
63   * Introduced specialized branching methods for dealing with "big Ms".
64   * Introduced new methods for dealing with symmetry (requires installation of [nauty](http://pallini.di.uniroma1.it/))
65   * Introduction of conflict cuts (off by default, turn on with `-constraint conflict`)
66
67 * Release 2.8.13
68
69   * Improved message handling
70   * Miscellaneous bug fixes.
71
72 * Release 2.8.12
73
74   * Update for dependencies.
75
76 * Release 2.8.11
77
78   * Major overhaul of C interface
79   * Fixes to SOS
80   * Miscellaneous bug fixes
81
82 * Release 2.8.10
83
84   * More changes related to thread safety.
85   * Fix bug in build system with Visual Studio compiler.
86   * Miscellaneous bug fixes.
87
88 * Release 2.8.9
89
90   * Attempt to make Cbc thread safe.
91   * Add parallel examples.
92   * Add CbcSolverUsefulInfo.
93   * Bug fixes.
94
95 * Release 2.8.8
96
97   * Added example to show how to use Cbc with installed libraries in MSVC++
98   * Fixed inconsistency in addition of libCbcSolver to dependencies in
99     {{{cbc_addlibs.txt}}}.
100
101 * Release 2.8.7
102
103   * Changed so that Doxygen builds LaTex
104   * Fixes for build system
105
106 * Release 2.8.6
107
108   * Added option to explicitly link dependencies to comply with packaging
109     requirements on Fedora and Debian, as well as allow building of MinGW
110     DLLs.
111
112 * Release 2.8.5
113
114   * Minor fixes to build system
115
116 * Release 2.8.4
117
118   * Small bug fixes
119   * Upgrades to build system
120
121 * Release 2.8.3:
122
123   * Fix for handling SOS.
124
125 * Release 2.8.2:
126
127   * Fixed recognition of Glpk source in main configure.
128   * Minor bug fixes in CoinUtils, Clp, and Cbc.
129
130 * Release 2.8.1:
131
132   * Minor bug fixes
133
134 * Release 2.8.0:
135
136   * Introduced new secondaryStatus 8 to indicate that solving stopped due to
137     an iteration limit.
138   * Solution pool is now accessible via the command line and the CbcMain*
139     interface.
140   * New mipstart option to read an initial feasible solution from a file.
141     Only values for discrete variables need to be provided.
142
143   * Added Proximity Search heuristic by Fischetti and Monaci (off by
144     default): The simplest way to switch it on using stand-alone version is
145     ```-proximity on```.
146
147     Proximity Search is the new "No-Neighborhood Search" 0-1 MIP refinement
148     heuristic recently proposed by Fischetti and Monaci (2012). The idea is
149     to define a sub-MIP without additional constraints but with a modified
150     objective function intended to attract the search in the proximity of the
151     incumbent. The approach works well for 0-1 MIPs whose solution landscape
152     is not too irregular (meaning the there is reasonable probability of
153     finding an improved solution by flipping a small number of binary
154     variables), in particular when it is applied to the first heuristic
155     solutions found at the root node.
156   
157   * An implementation of Zero-Half-Cuts by Alberto Caprara is now available.
158     By default, these cuts are off. To use add to your command line
159     -zerohalfCuts root (or other options) or just -zero. So far, they may
160     help only on a small subset of problems and may need some tuning.
161
162     The implementation of these cuts is described in G. Andreello, A.
163     Caprara, and M. Fischetti "Embedding Cuts in a Branch and Cut Framework:
164     a Computational Study with {0,1/2}-Cuts" INFORMS Journal on Computing
165     19(2), 229-238, 2007 http://dx.doi.org/10.1287/ijoc.1050.0162
166
167   * An alternative implementation of a reduce and split cut generator by
168     Giacomo Nannicini is now available. By default, these cuts are off. To
169     use add to your command line -reduce2AndSplitCuts root (or other
170     options).
171
172     The implementation of these cuts is described in G. Cornuejols and G.
173     Nannicini "Practical strategies for generating rank-1 split cuts in
174     mixed-integer linear programming" Mathematical Programming Computation
175     3(4), 281-318, 2011 http://dx.doi.org/10.1007/s12532-011-0028-6
176
177   * An alternative robust implementation of a Gomory cut generator by Giacomo
178     Nannicini is now available. By default, these cuts are off. To use add to
179     your command line -GMI root (or other options).
180
181     The implementation of these cuts is described in G. Cornuejols, F.
182     Margot, and G. Nannicini "On the safety of Gomory cut generators"
183     http://faculty.sutd.edu.sg/~nannicini/index.php?page=publications
184
185   * To encourage the use of some of the more exotic/expensive cut generators
186     a parameter -slowcutpasses has been added. The idea is that the code does
187     these cuts just a few times - less than the more usual cuts. The default
188     is 10. The cut generators identified by "may be slow" at present are just
189     Lift and project and ReduceAndSplit (both versions).
190   
191   * Allow initialization of random seed by user. Pseudo-random numbers are
192     used in Cbc and Clp. In Clp they are used to break ties in degenerate
193     problems, while in Cbc heuristics such as the Feasibility Pump use them
194     to decide whether to round up or down. So if a different pseudo-random
195     seed is given to Clp then you may get a different continuous optimum and
196     so different cuts and heuristic solutions. This can be switched on by
197     setting randomSeed for Clp and/or randomCbcSeed for Cbc. The special
198     value of 0 tells code to use time of day for initial seed.
199   
200   * Building on this idea, Andrea Lodi, Matteo Fischetti, Michele Monaci,
201     Domenico Salvagnin, Yuji Shinano, and Andrea Tramontani suggest that this
202     idea be improved by running at the root node with multiple copies of
203     solver, each with its own different seed and then passing in the
204     solutions and cuts so that the main solver has a richer set of solutions
205     and possibly stronger cuts. This is switched on by setting
206     -multipleRootPasses. These can also be done in parallel.
207 
208   * Few changes to presolve for special variables and badly scaled problems
209     (in CoinUtils).
210
211   * New option -extraVariables <number> which switches on a trivial
212    re-formulation that introduces extra integer variables to group together
213    variables with same cost.
214
215   * For some problems, cut generators and general branching work better if
216     the problem would be infeasible if the cost is too high. If the new
217     option -constraintFromCutoff is set, the objective function is added as a
218     constraint which rhs is set to the current cutoff value (objective value
219     of best known solution).
220
221 * Release 2.7.8:
222
223   * Change message when LP simplex iteration limit is hit from "Exiting on
224     maximum nodes" to "Exiting on maximum number of iterations"
225   * Fix for using overlapping SOS.
226   * Fixes in buildsystem.
227
228 * Release 2.7.7:
229
230   * Fix to report interruption on user event if SIGINT is received by
231     CbcSolver. model->status() should now be 5 if this event happened. Added
232     method CbcModel::sayEventHappened() to make cbc stop due to an 'user
233     event'.
234
235   * Other minor fixes.
236
237 * Release 2.7.6:
238
239   * Fixes to build system.
240
241   * Other minor fixes.
242
243 * Release 2.7.5:
244
245   * Fixes to get AMPL interface working again.
246
247   * More fixes to MSVC++ files.
248
249 * Release 2.7.4:
250
251   * Minor bugfixes.
252
253 * Release 2.7.3:
254
255   * Minor bugfixes.
256
257   * Fixes to MSVC++ files.
258
259 * Release 2.7.2:
260
261   * Allow row/column names for GMPL models.
262
263   * Added CbcModel::haveMultiThreadSupport() to indicate whether Cbc library
264     has been compiled with multithread support.
265
266   * Added CbcModel::waitingForMiniBranchAndBound() to indicate whether
267     sub-MIP heuristic is currently running.
268
269   * Cbc shell should work with readline if configured with
270     ```--enable-gnu-packages```.
271
272   * Support for compressed input files (.gz, .bz2) is now enabled by default.
273
274   * Fix problems with relative gap tolerance > 100% and further bugs.
275
276   * Fixes for MSVC++ Version 9 files.
277
278   * Minor fixes in buildsystem; update to BuildTools 0.7.1.
279
280 * Release 2.7.1:
281
282   * Fixes to MSVC++ files
283
284 * Release 2.7.0:
285
286   * License has been changed to the EPL.
287
288   * Support for MSVC++ version 10 added.
289
290   * Support for BuildTools version 0.7 to incorporate recent enhancements,
291     including proper library versioning in Linux, prohibiting installation of
292     private headers, etc.
293
294   * Updated externals to new stable versions of dependent projects.
295
296   * Improvements to heuristics.
297
298   * New options for cut generation.
299
300   * Improved reporting of results.
301
302   * Improvements to documentation.
303
304   * Minor bug fixes.
305
306
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