source: stable/2.9/Cbc/README @ 2158

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11(somehwat outdated) user's manual is available here: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