source: trunk/Cbc/README @ 1884

Last change on this file since 1884 was 1884, checked in by stefan, 6 years ago

update changelog according to john's mail from 19th of March (cbc list)

http://list.coin-or.org/pipermail/cbc/2013-March/001061.html

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
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1CBC README
2==========
3
4Welcome to the README for the COIN Branch and Cut Solver (CBC). CBC is
5distributed under the Eclipse Public License and is freely redistributable.
6All source code and documentation is Copyright IBM and others. This README may
7be redistributed freely.
8
9DOCUMENTATION
10=============
11
12For a quick start guide, please see the INSTALL file in this distribution. A (somehwat outdated) user's manual is available here:
13
14http://www.coin-or.org/Cbc
15
16More up-to-date automatically generated documentation of the source code can
17be found here:
18
19http://www.coin-or.org/Doxygen/Cbc/
20
21Further information can be found here:
22
23http://projects.coin-or.org/Cbc
24
25WHAT'S NEW
26==========
27
28Release 2.8.0:
29
301. Introduced new secondaryStatus 8 to indicate that solving stopped due to an iteration limit.
31
322. Solution pool is now accessible via the command line and the CbcMain* interface.
33
343. New mipstart option to read an initial feasible solution from a file. Only values for discrete
35   variables need to be provided.
36
374. Added Proximity Search heuristic by Fischetti and Monaci (off by default):
38   The simplest way to switch it on using stand-alone version is "-proximity on".
39
40   Proximity Search is the new "No-Neighborhood Search" 0-1 MIP refinement heuristic recently proposed by
41   Fischetti and Monaci (2012). The idea is to define a sub-MIP without additional constraints but with a
42   modified objective function intended to attract the search in the proximity of the incumbent. The approach
43   works well for 0-1 MIPs whose solution landscape is not too irregular (meaning the there is reasonable
44   probability of finding an improved solution by flipping a small number of binary variables), in particular
45   when it is applied to the first heuristic solutions found at the root node.
46   
475. An implementation of Zero-Half-Cuts by Alberto Caprara is now available.
48   By default, these cuts are off.  To use add to your command line -zerohalfCuts root (or other options) or just -zero.
49   So far, they may help only on a small subset of problems and may need some tuning.
50
51   The implementation of these cuts is described in
52   G. Andreello, A. Caprara, and M. Fischetti
53   "Embedding Cuts in a Branch and Cut Framework: a Computational Study with {0,1/2}-Cuts"
54   INFORMS Journal on Computing 19(2), 229-238, 2007
55   http://dx.doi.org/10.1287/ijoc.1050.0162
56
576. An alternative implementation of a reduce and split cut generator by Giacomo Nannicini is now available.
58   By default, these cuts are off.  To use add to your command line -reduce2AndSplitCuts root (or other options).
59
60   The implementation of these cuts is described in
61   G. Cornuejols and G. Nannicini
62   "Practical strategies for generating rank-1 split cuts in mixed-integer linear programming"
63   Mathematical Programming Computation 3(4), 281-318, 2011
64   http://dx.doi.org/10.1007/s12532-011-0028-6
65
667. An alternative robust implementation of a Gomory cut generator by Giacomo Nannicini is now available.
67   By default, these cuts are off.  To use add to your command line -GMI root (or other options).
68
69   The implementation of these cuts is described in
70   G. Cornuejols, F. Margot, and G. Nannicini
71   "On the safety of Gomory cut generators"
72   http://faculty.sutd.edu.sg/~nannicini/index.php?page=publications
73   
748.  Allow initialization of random seed by user.  Pseudo-random numbers are used in Cbc and Clp.  In Clp they
75   are used to break ties in degenerate problems, while in Cbc heuristics such as the Feasibility Pump use them   
76   to decide whether to round up or down.  So if a different pseudo-random seed is given to Clp then you may get
77   a different continuous optimum and so different cuts and heuristic solutions. This can be switched on by
78   setting randomSeed for Clp and/or randomCbcSeed for Cbc.  The special value of 0 tells code to use time of day
79   for initial seed.
80   
819.  Building on this idea Andrea Lodi, Matteo Fischetti, Michele Monaci, Domenico Salvagnin and Andrea Tramontani
82   suggest that this idea be be improved by running at the root node with multiple copies of solver, each
83   with its own different seed and then passing in the solutions and cuts so that the main solver has a richer
84   set of solutions and possibly stronger cuts.  This is switched on by setting multipleRootPasses.  These can also
85   be done in parallel.
86 
8710. Few changes to presolve for special variables and badly scaled problems (in CoinUtils).
88
8911. New option -extraVariables <number> which switches on a trivial re-formulation to group variables with same cost together.
90
91
92Release 2.7.8:
93   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.7&new_path=%2Freleases%2F2.7.8 to see all changes.
94
951. Change message when LP simplex iteration limit is hit from "Exiting on maximum nodes"
96   to "Exiting on maximum number of iterations"
97
982. Fix for using overlapping SOS.
99
1003. Fixes in buildsystem.
101
102Release 2.7.7:
103   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.6&new_path=%2Freleases%2F2.7.7 to see all changes.
104
1051. Fix to report interruption on user event if SIGINT is received by CbcSolver.
106   model->status() should now be 5 if this event happened.
107   Added method CbcModel::sayEventHappened() to make cbc stop due to an 'user event'.
108
1092. Other minor fixes.
110
111Release 2.7.6:
112   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.5&new_path=%2Freleases%2F2.7.6 to see all changes.
113
1141. Fixes to build system.
115
1162. Other minor fixes.
117
118Release 2.7.5:
119   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.4&new_path=%2Freleases%2F2.7.5 to see all changes.
120
1211. Fixes to get AMPL interface working again.
122
1232. More fixes to MSVC++ files.
124
125Release 2.7.4:
126   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.3&new_path=%2Freleases%2F2.7.4 to see all changes.
127
1281. Minor bugfixes.
129
130Release 2.7.3:
131   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.2&new_path=%2Freleases%2F2.7.3 to see all changes.
132
1331. Minor bugfixes.
134
1352. Fixes to MSVC++ files.
136
137Release 2.7.2:
138   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.1&new_path=%2Freleases%2F2.7.2 to see all changes.
139
1401. Allow row/column names for GMPL models.
141
1422. Added CbcModel::haveMultiThreadSupport() to indicate whether Cbc library has been compiled with multithread support.
143
1443. Added CbcModel::waitingForMiniBranchAndBound() to indicate whether sub-MIP heuristic is currently running.
145
1464. Cbc shell should work with readline if configured with --enable-gnu-packages.
147
1485. Support for compressed input files (.gz, .bz2) is now enabled by default.
149
1506. Fix problems with relative gap tolerance > 100% and further bugs.
151
1527. Fixes for MSVC++ Version 9 files.
153
1548. Minor fixes in buildsystem; update to BuildTools 0.7.1.
155
156Release 2.7.1:
157   Look at https://projects.coin-or.org/Cbc/changeset?old_path=%2Freleases%2F2.7.0&new_path=%2Freleases%2F2.7.1 to see all changes.
158
1591. Fixes to MSVC++ files
160
161Release 2.7.0:
162
1631. License has been changed to the EPL.
164
1652. Support for MSVC++ version 10 added.
166
1673. Support for BuildTools version 0.7 to incorporate recent enhancements,
168including proper library versioning in Linux, prohibiting installation of
169private headers, etc.
170
1714. Updated externals to new stable versions of dependent projects.
172
1735. Improvements to heuristics.
174
1756. New options for cut generation.
176
1777. Improved reporting of results.
178
1798. Improvements to documentation.
180
1819. Minor bug fixes.
182
183SUPPORT
184=======
185
1861. List Serve
187
188CBC users should use the Cbc mailing list. To subscribe, go to
189http://list.coin-or.org/mailman/listinfo/cbc
190
1913. Bug Reports
192
193Bug reports should be reported on the CBC development web site at
194
195https://projects.coin-or.org/Cbc/newticket
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