source: stable/2.9/README.md @ 2142

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1# CBC Version 2.9.2 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11(somehwat outdated) user's manual is available here: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 5.9.2
40
41   * Fix for proper installation with ```DESTDIR```
42
43 * Release 5.9.1
44
45   * Fix for dependency linking
46   * Minor bug fixes
47
48 * Release 5.9.0
49   * Major algorithmic improvements
50
51 * Release 5.8.13
52   * Improved message handling
53   * Miscellaneous bug fixes.
54
55 * Release 5.8.12
56   * Update for dependencies.
57
58 * Release 5.8.11
59   * Major overhaul of C interface
60   * Fixes to SOS
61   * Miscellaneous bug fixes
62
63 * Release 5.8.10
64   * More changes related to thread safety.
65   * Fix bug in build system with Visual Studio compiler.
66   * Miscellaneous bug fixes.
67
68 * Release 5.8.9
69   * Attempt to make Cbc thread safe.
70   * Add parallel examples.
71   * Add CbcSolverUsefulInfo.
72   * Bug fixes.
73
74 * Release 5.8.8
75
76   * Added example to show how to use Cbc with installed libraries in MSVC++
77   * Fixed inconsistency in addition of libCbcSolver to dependencies in
78     {{{cbc_addlibs.txt}}}.
79
80 * Release 5.8.7
81
82   * Changed so that Doxygen builds LaTex
83   * Fixes for build system
84
85 * Release 5.8.6
86
87   * Added option to explicitly link dependencies to comply with packaging
88     requirements on Fedora and Debian, as well as allow building of MinGW
89     DLLs.
90
91 * Release 5.8.5
92   * Minor fixes to build system
93
94 * Release 5.8.4
95   * Small bug fixes
96   * Upgrades to build system
97
98 * Release 2.8.3:
99
100   * Fix for handling SOS.
101
102 * Release 2.8.2:
103
104   * Fixed recognition of Glpk source in main configure.
105   * Minor bug fixes in CoinUtils, Clp, and Cbc.
106
107 * Release 2.8.1:
108
109   * Minor bug fixes
110
111 * Release 2.8.0:
112
113   * Introduced new secondaryStatus 8 to indicate that solving stopped due to
114     an iteration limit.
115   * Solution pool is now accessible via the command line and the CbcMain*
116     interface.
117   * New mipstart option to read an initial feasible solution from a file.
118     Only values for discrete variables need to be provided.
119
120   * Added Proximity Search heuristic by Fischetti and Monaci (off by
121     default): The simplest way to switch it on using stand-alone version is
122     ```-proximity on```.
123
124     Proximity Search is the new "No-Neighborhood Search" 0-1 MIP refinement
125     heuristic recently proposed by Fischetti and Monaci (2012). The idea is
126     to define a sub-MIP without additional constraints but with a modified
127     objective function intended to attract the search in the proximity of the
128     incumbent. The approach works well for 0-1 MIPs whose solution landscape
129     is not too irregular (meaning the there is reasonable probability of
130     finding an improved solution by flipping a small number of binary
131     variables), in particular when it is applied to the first heuristic
132     solutions found at the root node.
133   
134   * An implementation of Zero-Half-Cuts by Alberto Caprara is now available.
135     By default, these cuts are off. To use add to your command line
136     -zerohalfCuts root (or other options) or just -zero. So far, they may
137     help only on a small subset of problems and may need some tuning.
138
139     The implementation of these cuts is described in G. Andreello, A.
140     Caprara, and M. Fischetti "Embedding Cuts in a Branch and Cut Framework:
141     a Computational Study with {0,1/2}-Cuts" INFORMS Journal on Computing
142     19(2), 229-238, 2007 http://dx.doi.org/10.1287/ijoc.1050.0162
143
144   * An alternative implementation of a reduce and split cut generator by
145     Giacomo Nannicini is now available. By default, these cuts are off. To
146     use add to your command line -reduce2AndSplitCuts root (or other
147     options).
148
149     The implementation of these cuts is described in G. Cornuejols and G.
150     Nannicini "Practical strategies for generating rank-1 split cuts in
151     mixed-integer linear programming" Mathematical Programming Computation
152     3(4), 281-318, 2011 http://dx.doi.org/10.1007/s12532-011-0028-6
153
154   * An alternative robust implementation of a Gomory cut generator by Giacomo
155     Nannicini is now available. By default, these cuts are off. To use add to
156     your command line -GMI root (or other options).
157
158     The implementation of these cuts is described in G. Cornuejols, F.
159     Margot, and G. Nannicini "On the safety of Gomory cut generators"
160     http://faculty.sutd.edu.sg/~nannicini/index.php?page=publications
161
162   * To encourage the use of some of the more exotic/expensive cut generators
163     a parameter -slowcutpasses has been added. The idea is that the code does
164     these cuts just a few times - less than the more usual cuts. The default
165     is 10. The cut generators identified by "may be slow" at present are just
166     Lift and project and ReduceAndSplit (both versions).
167   
168   * Allow initialization of random seed by user. Pseudo-random numbers are
169     used in Cbc and Clp. In Clp they are used to break ties in degenerate
170     problems, while in Cbc heuristics such as the Feasibility Pump use them
171     to decide whether to round up or down. So if a different pseudo-random
172     seed is given to Clp then you may get a different continuous optimum and
173     so different cuts and heuristic solutions. This can be switched on by
174     setting randomSeed for Clp and/or randomCbcSeed for Cbc. The special
175     value of 0 tells code to use time of day for initial seed.
176   
177   * Building on this idea, Andrea Lodi, Matteo Fischetti, Michele Monaci,
178     Domenico Salvagnin, Yuji Shinano, and Andrea Tramontani suggest that this
179     idea be improved by running at the root node with multiple copies of
180     solver, each with its own different seed and then passing in the
181     solutions and cuts so that the main solver has a richer set of solutions
182     and possibly stronger cuts. This is switched on by setting
183     -multipleRootPasses. These can also be done in parallel.
184 
185   * Few changes to presolve for special variables and badly scaled problems
186     (in CoinUtils).
187
188   * New option -extraVariables <number> which switches on a trivial
189    re-formulation that introduces extra integer variables to group together
190    variables with same cost.
191
192   * For some problems, cut generators and general branching work better if
193     the problem would be infeasible if the cost is too high. If the new
194     option -constraintFromCutoff is set, the objective function is added as a
195     constraint which rhs is set to the current cutoff value (objective value
196     of best known solution).
197
198 * Release 2.7.8:
199
200   * Change message when LP simplex iteration limit is hit from "Exiting on
201     maximum nodes" to "Exiting on maximum number of iterations"
202   * Fix for using overlapping SOS.
203   * Fixes in buildsystem.
204
205 * Release 2.7.7:
206
207   * Fix to report interruption on user event if SIGINT is received by
208     CbcSolver. model->status() should now be 5 if this event happened. Added
209     method CbcModel::sayEventHappened() to make cbc stop due to an 'user
210     event'.
211
212   * Other minor fixes.
213
214 * Release 2.7.6:
215
216   * Fixes to build system.
217
218   * Other minor fixes.
219
220 * Release 2.7.5:
221
222   * Fixes to get AMPL interface working again.
223
224   * More fixes to MSVC++ files.
225
226 * Release 2.7.4:
227
228   * Minor bugfixes.
229
230 * Release 2.7.3:
231
232   * Minor bugfixes.
233
234   * Fixes to MSVC++ files.
235
236 * Release 2.7.2:
237
238   * Allow row/column names for GMPL models.
239
240   * Added CbcModel::haveMultiThreadSupport() to indicate whether Cbc library
241     has been compiled with multithread support.
242
243   * Added CbcModel::waitingForMiniBranchAndBound() to indicate whether
244     sub-MIP heuristic is currently running.
245
246   * Cbc shell should work with readline if configured with
247     ```--enable-gnu-packages```.
248
249   * Support for compressed input files (.gz, .bz2) is now enabled by default.
250
251   * Fix problems with relative gap tolerance > 100% and further bugs.
252
253   * Fixes for MSVC++ Version 9 files.
254
255   * Minor fixes in buildsystem; update to BuildTools 0.7.1.
256
257 * Release 2.7.1:
258
259   * Fixes to MSVC++ files
260
261 * Release 2.7.0:
262
263   * License has been changed to the EPL.
264
265   * Support for MSVC++ version 10 added.
266
267   * Support for BuildTools version 0.7 to incorporate recent enhancements,
268     including proper library versioning in Linux, prohibiting installation of
269     private headers, etc.
270
271   * Updated externals to new stable versions of dependent projects.
272
273   * Improvements to heuristics.
274
275   * New options for cut generation.
276
277   * Improved reporting of results.
278
279   * Improvements to documentation.
280
281   * Minor bug fixes.
282
283
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