source: stable/2.9/Cbc/README @ 2274

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1# CBC Version 2.9.4 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11(somehwat outdated) user's manual is available here: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 2.9.8
40
41   * Update to most current releases of dependencies
42   * Small bug fixes
43   * Add support for automatic build and test with Travis and Appveyor
44
45* Release 2.9.7
46
47   * Small bug fixes
48   * Option to switch to line buffered output
49
50 * Release 2.9.6
51
52   * Small bug fixes
53
54 * Release 2.9.5
55
56   * Small bug fixes
57
58 * Release 2.9.4
59
60   * Small fixes for stability
61   * Fixes for Doygen documentation generation
62
63 * Release 2.9.3
64
65   * Minor bug fixes
66
67 * Release 2.9.2
68
69   * Fix for proper installation with ```DESTDIR```
70
71 * Release 2.9.1
72
73   * Fix for dependency linking
74   * Minor bug fixes
75
76 * Release 2.9.0
77
78   * Introduced specialized branching methods for dealing with "big Ms".
79   * Introduced new methods for dealing with symmetry (requires installation of [nauty](http://pallini.di.uniroma1.it/))
80   * Introduction of conflict cuts (off by default, turn on with `-constraint conflict`)
81
82 * Release 2.8.13
83
84   * Improved message handling
85   * Miscellaneous bug fixes.
86
87 * Release 2.8.12
88   * Update for dependencies.
89
90 * Release 5.8.11
91
92   * Major overhaul of C interface
93   * Fixes to SOS
94   * Miscellaneous bug fixes
95
96 * Release 2.8.10
97
98   * More changes related to thread safety.
99   * Fix bug in build system with Visual Studio compiler.
100   * Miscellaneous bug fixes.
101
102 * Release 2.8.9
103
104   * Attempt to make Cbc thread safe.
105   * Add parallel examples.
106   * Add CbcSolverUsefulInfo.
107   * Bug fixes.
108
109 * Release 2.8.8
110
111   * Added example to show how to use Cbc with installed libraries in MSVC++
112   * Fixed inconsistency in addition of libCbcSolver to dependencies in
113     {{{cbc_addlibs.txt}}}.
114
115 * Release 2.8.7
116
117   * Changed so that Doxygen builds LaTex
118   * Fixes for build system
119
120 * Release 2.8.6
121
122   * Added option to explicitly link dependencies to comply with packaging
123     requirements on Fedora and Debian, as well as allow building of MinGW
124     DLLs.
125
126 * Release 2.8.5
127
128   * Minor fixes to build system
129
130 * Release 2.8.4
131   * Small bug fixes
132   * Upgrades to build system
133
134 * Release 2.8.3:
135
136   * Fix for handling SOS.
137
138 * Release 2.8.2:
139
140   * Fixed recognition of Glpk source in main configure.
141   * Minor bug fixes in CoinUtils, Clp, and Cbc.
142
143 * Release 2.8.1:
144
145   * Minor bug fixes
146
147 * Release 2.8.0:
148
149   * Introduced new secondaryStatus 8 to indicate that solving stopped due to
150     an iteration limit.
151   * Solution pool is now accessible via the command line and the CbcMain*
152     interface.
153   * New mipstart option to read an initial feasible solution from a file.
154     Only values for discrete variables need to be provided.
155
156   * Added Proximity Search heuristic by Fischetti and Monaci (off by
157     default): The simplest way to switch it on using stand-alone version is
158     ```-proximity on```.
159
160     Proximity Search is the new "No-Neighborhood Search" 0-1 MIP refinement
161     heuristic recently proposed by Fischetti and Monaci (2012). The idea is
162     to define a sub-MIP without additional constraints but with a modified
163     objective function intended to attract the search in the proximity of the
164     incumbent. The approach works well for 0-1 MIPs whose solution landscape
165     is not too irregular (meaning the there is reasonable probability of
166     finding an improved solution by flipping a small number of binary
167     variables), in particular when it is applied to the first heuristic
168     solutions found at the root node.
169   
170   * An implementation of Zero-Half-Cuts by Alberto Caprara is now available.
171     By default, these cuts are off. To use add to your command line
172     -zerohalfCuts root (or other options) or just -zero. So far, they may
173     help only on a small subset of problems and may need some tuning.
174
175     The implementation of these cuts is described in G. Andreello, A.
176     Caprara, and M. Fischetti "Embedding Cuts in a Branch and Cut Framework:
177     a Computational Study with {0,1/2}-Cuts" INFORMS Journal on Computing
178     19(2), 229-238, 2007 http://dx.doi.org/10.1287/ijoc.1050.0162
179
180   * An alternative implementation of a reduce and split cut generator by
181     Giacomo Nannicini is now available. By default, these cuts are off. To
182     use add to your command line -reduce2AndSplitCuts root (or other
183     options).
184
185     The implementation of these cuts is described in G. Cornuejols and G.
186     Nannicini "Practical strategies for generating rank-1 split cuts in
187     mixed-integer linear programming" Mathematical Programming Computation
188     3(4), 281-318, 2011 http://dx.doi.org/10.1007/s12532-011-0028-6
189
190   * An alternative robust implementation of a Gomory cut generator by Giacomo
191     Nannicini is now available. By default, these cuts are off. To use add to
192     your command line -GMI root (or other options).
193
194     The implementation of these cuts is described in G. Cornuejols, F.
195     Margot, and G. Nannicini "On the safety of Gomory cut generators"
196     http://faculty.sutd.edu.sg/~nannicini/index.php?page=publications
197
198   * To encourage the use of some of the more exotic/expensive cut generators
199     a parameter -slowcutpasses has been added. The idea is that the code does
200     these cuts just a few times - less than the more usual cuts. The default
201     is 10. The cut generators identified by "may be slow" at present are just
202     Lift and project and ReduceAndSplit (both versions).
203   
204   * Allow initialization of random seed by user. Pseudo-random numbers are
205     used in Cbc and Clp. In Clp they are used to break ties in degenerate
206     problems, while in Cbc heuristics such as the Feasibility Pump use them
207     to decide whether to round up or down. So if a different pseudo-random
208     seed is given to Clp then you may get a different continuous optimum and
209     so different cuts and heuristic solutions. This can be switched on by
210     setting randomSeed for Clp and/or randomCbcSeed for Cbc. The special
211     value of 0 tells code to use time of day for initial seed.
212   
213   * Building on this idea, Andrea Lodi, Matteo Fischetti, Michele Monaci,
214     Domenico Salvagnin, Yuji Shinano, and Andrea Tramontani suggest that this
215     idea be improved by running at the root node with multiple copies of
216     solver, each with its own different seed and then passing in the
217     solutions and cuts so that the main solver has a richer set of solutions
218     and possibly stronger cuts. This is switched on by setting
219     -multipleRootPasses. These can also be done in parallel.
220 
221   * Few changes to presolve for special variables and badly scaled problems
222     (in CoinUtils).
223
224   * New option -extraVariables <number> which switches on a trivial
225    re-formulation that introduces extra integer variables to group together
226    variables with same cost.
227
228   * For some problems, cut generators and general branching work better if
229     the problem would be infeasible if the cost is too high. If the new
230     option -constraintFromCutoff is set, the objective function is added as a
231     constraint which rhs is set to the current cutoff value (objective value
232     of best known solution).
233
234 * Release 2.7.8:
235
236   * Change message when LP simplex iteration limit is hit from "Exiting on
237     maximum nodes" to "Exiting on maximum number of iterations"
238   * Fix for using overlapping SOS.
239   * Fixes in buildsystem.
240
241 * Release 2.7.7:
242
243   * Fix to report interruption on user event if SIGINT is received by
244     CbcSolver. model->status() should now be 5 if this event happened. Added
245     method CbcModel::sayEventHappened() to make cbc stop due to an 'user
246     event'.
247
248   * Other minor fixes.
249
250 * Release 2.7.6:
251
252   * Fixes to build system.
253
254   * Other minor fixes.
255
256 * Release 2.7.5:
257
258   * Fixes to get AMPL interface working again.
259
260   * More fixes to MSVC++ files.
261
262 * Release 2.7.4:
263
264   * Minor bugfixes.
265
266 * Release 2.7.3:
267
268   * Minor bugfixes.
269
270   * Fixes to MSVC++ files.
271
272 * Release 2.7.2:
273
274   * Allow row/column names for GMPL models.
275
276   * Added CbcModel::haveMultiThreadSupport() to indicate whether Cbc library
277     has been compiled with multithread support.
278
279   * Added CbcModel::waitingForMiniBranchAndBound() to indicate whether
280     sub-MIP heuristic is currently running.
281
282   * Cbc shell should work with readline if configured with
283     ```--enable-gnu-packages```.
284
285   * Support for compressed input files (.gz, .bz2) is now enabled by default.
286
287   * Fix problems with relative gap tolerance > 100% and further bugs.
288
289   * Fixes for MSVC++ Version 9 files.
290
291   * Minor fixes in buildsystem; update to BuildTools 0.7.1.
292
293 * Release 2.7.1:
294
295   * Fixes to MSVC++ files
296
297 * Release 2.7.0:
298
299   * License has been changed to the EPL.
300
301   * Support for MSVC++ version 10 added.
302
303   * Support for BuildTools version 0.7 to incorporate recent enhancements,
304     including proper library versioning in Linux, prohibiting installation of
305     private headers, etc.
306
307   * Updated externals to new stable versions of dependent projects.
308
309   * Improvements to heuristics.
310
311   * New options for cut generation.
312
313   * Improved reporting of results.
314
315   * Improvements to documentation.
316
317   * Minor bug fixes.
318
319
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