source: stable/2.9/README.md @ 2261

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1# CBC Version 2.9.4 README
2
3[![Build Status](https://travis-ci.org/coin-or/Cbc.svg?branch=master)](https://travis-ci.org/coin-or/Cbc)
4
5Welcome to the README for the COIN Branch and Cut Solver (CBC). CBC is
6distributed under the Eclipse Public License and is freely redistributable.
7All source code and documentation is Copyright IBM and others. This README may
8be redistributed freely.
9
10## DOCUMENTATION
11
12For a quick start guide, please see the INSTALL file in this distribution. A
13(somehwat outdated) user's manual is available here:
14
15http://www.coin-or.org/Cbc
16
17More up-to-date automatically generated documentation of the source code can
18be found here:
19
20http://www.coin-or.org/Doxygen/Cbc/
21
22Further information can be found here:
23
24http://projects.coin-or.org/Cbc
25
26## SUPPORT
27
28### List Serve
29
30CBC users should use the Cbc mailing list. To subscribe, go to
31http://list.coin-or.org/mailman/listinfo/cbc
32
33### Bug Reports
34
35Bug reports should be reported on the CBC development web site at
36
37https://projects.coin-or.org/Cbc/newticket
38
39## CHANGELOG
40
41 * Release 2.9.7
42
43   * Small bug fixes
44   * Option to switch to line buffered output
45
46 * Release 2.9.6
47
48   * Small bug fixes
49
50 * Release 2.9.5
51
52   * Small bug fixes
53
54 * Release 2.9.4
55
56   * Small fixes for stability
57   * Fixes for Doygen documentation generation
58
59 * Release 2.9.3
60
61   * Minor bug fixes
62
63 * Release 2.9.2
64
65   * Fix for proper installation with ```DESTDIR```
66
67 * Release 2.9.1
68
69   * Fix for dependency linking
70   * Minor bug fixes
71
72 * Release 2.9.0
73
74   * Introduced specialized branching methods for dealing with "big Ms".
75   * Introduced new methods for dealing with symmetry (requires installation of [nauty](http://pallini.di.uniroma1.it/))
76   * Introduction of conflict cuts (off by default, turn on with `-constraint conflict`)
77
78 * Release 2.8.13
79
80   * Improved message handling
81   * Miscellaneous bug fixes.
82
83 * Release 2.8.12
84
85   * Update for dependencies.
86
87 * Release 2.8.11
88
89   * Major overhaul of C interface
90   * Fixes to SOS
91   * Miscellaneous bug fixes
92
93 * Release 2.8.10
94
95   * More changes related to thread safety.
96   * Fix bug in build system with Visual Studio compiler.
97   * Miscellaneous bug fixes.
98
99 * Release 2.8.9
100
101   * Attempt to make Cbc thread safe.
102   * Add parallel examples.
103   * Add CbcSolverUsefulInfo.
104   * Bug fixes.
105
106 * Release 2.8.8
107
108   * Added example to show how to use Cbc with installed libraries in MSVC++
109   * Fixed inconsistency in addition of libCbcSolver to dependencies in
110     {{{cbc_addlibs.txt}}}.
111
112 * Release 2.8.7
113
114   * Changed so that Doxygen builds LaTex
115   * Fixes for build system
116
117 * Release 2.8.6
118
119   * Added option to explicitly link dependencies to comply with packaging
120     requirements on Fedora and Debian, as well as allow building of MinGW
121     DLLs.
122
123 * Release 2.8.5
124
125   * Minor fixes to build system
126
127 * Release 2.8.4
128
129   * Small bug fixes
130   * Upgrades to build system
131
132 * Release 2.8.3:
133
134   * Fix for handling SOS.
135
136 * Release 2.8.2:
137
138   * Fixed recognition of Glpk source in main configure.
139   * Minor bug fixes in CoinUtils, Clp, and Cbc.
140
141 * Release 2.8.1:
142
143   * Minor bug fixes
144
145 * Release 2.8.0:
146
147   * Introduced new secondaryStatus 8 to indicate that solving stopped due to
148     an iteration limit.
149   * Solution pool is now accessible via the command line and the CbcMain*
150     interface.
151   * New mipstart option to read an initial feasible solution from a file.
152     Only values for discrete variables need to be provided.
153
154   * Added Proximity Search heuristic by Fischetti and Monaci (off by
155     default): The simplest way to switch it on using stand-alone version is
156     ```-proximity on```.
157
158     Proximity Search is the new "No-Neighborhood Search" 0-1 MIP refinement
159     heuristic recently proposed by Fischetti and Monaci (2012). The idea is
160     to define a sub-MIP without additional constraints but with a modified
161     objective function intended to attract the search in the proximity of the
162     incumbent. The approach works well for 0-1 MIPs whose solution landscape
163     is not too irregular (meaning the there is reasonable probability of
164     finding an improved solution by flipping a small number of binary
165     variables), in particular when it is applied to the first heuristic
166     solutions found at the root node.
167   
168   * An implementation of Zero-Half-Cuts by Alberto Caprara is now available.
169     By default, these cuts are off. To use add to your command line
170     -zerohalfCuts root (or other options) or just -zero. So far, they may
171     help only on a small subset of problems and may need some tuning.
172
173     The implementation of these cuts is described in G. Andreello, A.
174     Caprara, and M. Fischetti "Embedding Cuts in a Branch and Cut Framework:
175     a Computational Study with {0,1/2}-Cuts" INFORMS Journal on Computing
176     19(2), 229-238, 2007 http://dx.doi.org/10.1287/ijoc.1050.0162
177
178   * An alternative implementation of a reduce and split cut generator by
179     Giacomo Nannicini is now available. By default, these cuts are off. To
180     use add to your command line -reduce2AndSplitCuts root (or other
181     options).
182
183     The implementation of these cuts is described in G. Cornuejols and G.
184     Nannicini "Practical strategies for generating rank-1 split cuts in
185     mixed-integer linear programming" Mathematical Programming Computation
186     3(4), 281-318, 2011 http://dx.doi.org/10.1007/s12532-011-0028-6
187
188   * An alternative robust implementation of a Gomory cut generator by Giacomo
189     Nannicini is now available. By default, these cuts are off. To use add to
190     your command line -GMI root (or other options).
191
192     The implementation of these cuts is described in G. Cornuejols, F.
193     Margot, and G. Nannicini "On the safety of Gomory cut generators"
194     http://faculty.sutd.edu.sg/~nannicini/index.php?page=publications
195
196   * To encourage the use of some of the more exotic/expensive cut generators
197     a parameter -slowcutpasses has been added. The idea is that the code does
198     these cuts just a few times - less than the more usual cuts. The default
199     is 10. The cut generators identified by "may be slow" at present are just
200     Lift and project and ReduceAndSplit (both versions).
201   
202   * Allow initialization of random seed by user. Pseudo-random numbers are
203     used in Cbc and Clp. In Clp they are used to break ties in degenerate
204     problems, while in Cbc heuristics such as the Feasibility Pump use them
205     to decide whether to round up or down. So if a different pseudo-random
206     seed is given to Clp then you may get a different continuous optimum and
207     so different cuts and heuristic solutions. This can be switched on by
208     setting randomSeed for Clp and/or randomCbcSeed for Cbc. The special
209     value of 0 tells code to use time of day for initial seed.
210   
211   * Building on this idea, Andrea Lodi, Matteo Fischetti, Michele Monaci,
212     Domenico Salvagnin, Yuji Shinano, and Andrea Tramontani suggest that this
213     idea be improved by running at the root node with multiple copies of
214     solver, each with its own different seed and then passing in the
215     solutions and cuts so that the main solver has a richer set of solutions
216     and possibly stronger cuts. This is switched on by setting
217     -multipleRootPasses. These can also be done in parallel.
218 
219   * Few changes to presolve for special variables and badly scaled problems
220     (in CoinUtils).
221
222   * New option -extraVariables <number> which switches on a trivial
223    re-formulation that introduces extra integer variables to group together
224    variables with same cost.
225
226   * For some problems, cut generators and general branching work better if
227     the problem would be infeasible if the cost is too high. If the new
228     option -constraintFromCutoff is set, the objective function is added as a
229     constraint which rhs is set to the current cutoff value (objective value
230     of best known solution).
231
232 * Release 2.7.8:
233
234   * Change message when LP simplex iteration limit is hit from "Exiting on
235     maximum nodes" to "Exiting on maximum number of iterations"
236   * Fix for using overlapping SOS.
237   * Fixes in buildsystem.
238
239 * Release 2.7.7:
240
241   * Fix to report interruption on user event if SIGINT is received by
242     CbcSolver. model->status() should now be 5 if this event happened. Added
243     method CbcModel::sayEventHappened() to make cbc stop due to an 'user
244     event'.
245
246   * Other minor fixes.
247
248 * Release 2.7.6:
249
250   * Fixes to build system.
251
252   * Other minor fixes.
253
254 * Release 2.7.5:
255
256   * Fixes to get AMPL interface working again.
257
258   * More fixes to MSVC++ files.
259
260 * Release 2.7.4:
261
262   * Minor bugfixes.
263
264 * Release 2.7.3:
265
266   * Minor bugfixes.
267
268   * Fixes to MSVC++ files.
269
270 * Release 2.7.2:
271
272   * Allow row/column names for GMPL models.
273
274   * Added CbcModel::haveMultiThreadSupport() to indicate whether Cbc library
275     has been compiled with multithread support.
276
277   * Added CbcModel::waitingForMiniBranchAndBound() to indicate whether
278     sub-MIP heuristic is currently running.
279
280   * Cbc shell should work with readline if configured with
281     ```--enable-gnu-packages```.
282
283   * Support for compressed input files (.gz, .bz2) is now enabled by default.
284
285   * Fix problems with relative gap tolerance > 100% and further bugs.
286
287   * Fixes for MSVC++ Version 9 files.
288
289   * Minor fixes in buildsystem; update to BuildTools 0.7.1.
290
291 * Release 2.7.1:
292
293   * Fixes to MSVC++ files
294
295 * Release 2.7.0:
296
297   * License has been changed to the EPL.
298
299   * Support for MSVC++ version 10 added.
300
301   * Support for BuildTools version 0.7 to incorporate recent enhancements,
302     including proper library versioning in Linux, prohibiting installation of
303     private headers, etc.
304
305   * Updated externals to new stable versions of dependent projects.
306
307   * Improvements to heuristics.
308
309   * New options for cut generation.
310
311   * Improved reporting of results.
312
313   * Improvements to documentation.
314
315   * Minor bug fixes.
316
317
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