The COIN-OR Branch and Cut (Cbc) solver is an open-source mixed-integer linear programming solver written in C++. Problems for Cbc can be submitted on the NEOS server in AMPL, GAMS, or MPS format.
Cbc is intended to be used primarily as a callable library to create customized branch-and-cut solvers, however, a basic stand-alone executable is used to solve problems submitted to the NEOS Server. Cbc utilizes other COIN-OR projects Cgl (Cut Generation Library) to generate cutting planes and Cpl to solve the linear programs at each node of the tree.
Cbc was developed by John Forrest, now retired from IBM Research. The project is currently managed by John Forrest and Ted Ralphs. For more information on Cbc and the COIN-OR initiative, please visit the Cbc COIN-OR website.
The user must submit a model in GAMS format to solve an optimization problem. For security purposes, the model submitted must adhere to the following conventions:
If you are unfamiliar with GAMS, the GAMS Documentation includes a GAMS Tutorial and User's Guide. Examples of models in GAMS format can be found in the GAMS model library.
By default, the NEOS Server limits the amount of output generated in the listing file by turning off the symbol and unique element list, symbol cross references, and restricting the rows and columns listed to zero. This behavior can be changed by specifying the appropriate options in the model file. See the documentation on GAMS output for further information.
You may optionally submit an options file if you wish to override the default parameter settings for the solver. Currently, the NEOS Server can only use optfile=1 with GAMS input. Therefore, any model that specifies a different options file will not work as intended.
<modelname>.optfile = 1 ;
optfile = 1