Interface to the Coin-OR Cbc solver for mixed-integer programming
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Updated Last
2 Years Ago
Started In
January 2013

COIN-OR Branch and Cut Interface (Cbc.jl)

Cbc.jl is an interface to the COIN-OR Branch and Cut solver. It provides a complete interface to the low-level C API, as well as an implementation of the solver-independent MathOptInterface API's

Note: This wrapper is maintained by the JuMP community and is not a COIN-OR project.

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The package can be installed with Pkg.add.

import Pkg

In addition to installing the Cbc.jl package, this will also download and install the Cbc binaries. (You do not need to install Cbc separately.) If you require a custom build of Cbc, see the Custom Installation instructions below.

Using with JuMP

Use Cbc.Optimizer to use Cbc with JuMP:

using Cbc
using JuMP
model = Model(Cbc.Optimizer)
set_optimizer_attribute(model, "logLevel", 1)


Options are, unfortunately, not well documented.

The following options are likely to be the most useful:

  • seconds -- Solution timeout limit.

    For example, set_optimizer_attribute(model, "seconds", 60.0).

  • logLevel -- Set to 1 to enable solution output.

    For example, set_optimizer_attribute(model, "logLevel", 1).

  • maxSolutions -- Terminate after this many feasible solutions have been found.

    For example, set_optimizer_attribute(model, "maxSolutions", 1).

  • maxNodes -- Terminate after this many branch-and-bound nodes have been evaluated.

    For example, set_optimizer_attribute(model, "maxNodes", 1).

  • allowableGap -- Terminate after optimality gap is less than this value (on an absolute scale).

    For example, set_optimizer_attribute(model, "allowableGap", 0.05).

  • ratioGap -- Terminate after optimality gap is smaller than this relative fraction.

    For example, set_optimizer_attribute(model, "allowableGap", 0.05).

  • threads -- Set the number of threads to use for parallel branch & bound.

    For example, set_optimizer_attribute(model, "threads", 2).

The complete list of parameters can be found by running the cbc executable and typing ? at the prompt.

On Julia 1.3 and above, you can start the cbc executable from Julia as follows:

using Cbc_jll
Cbc_jll.cbc() do exe

Custom Installation

To install custom built Cbc binaries, use the environmental variable JULIA_CBC_LIBRARY_PATH to point to the path at which you installed Cbc (the folder containing libCbcSolver). For example, on Mac, after installing Cbc with brew install cbc, use:

ENV["JULIA_CBC_LIBRARY_PATH"] = "/usr/local/Cellar/cbc/2.10.5/lib"
import Pkg

Replace "/usr/local/Cellar/cbc/2.10.5/lib" with a different path as appropriate.

You must have JULIA_CBC_LIBRARY_PATH set every time you run using Cbc, not just when you install it.

Switch back to the default binaries as follows:

import Pkg