source: stable/2.9/README.md @ 2219

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11(somehwat outdated) user's manual is available here: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