JaCoP.jl

JaCoP.jl is a wrapper for the JaCoP constraint-programming solver.

JaCoP.jl only proposes an implementation of the interface defined by MathOptInterface.jl and by ConstraintProgrammingExtensions.jl. It does not provide access to the low-level Java API.

Affiliation

This wrapper is maintained by the community and is not officially supported by the JaCoP project. If you are interested in official support for JaCoP in Julia, let them know!

Installation

Install JaCoP as follows:

import Pkg
Pkg.add("JaCoP")

The JaCoP library is automatically downloaded when building this package in a version that it supports. However, as JaCoP is a Java library, you will need a working JVM on your machine that is compatible with JavaCall.jl. Typically, this reduces to having access to a JVM in your PATH or JAVA_HOME environment variables. (If you want to use your own JaCoP binary, you can tweak the deps/deps.jl that is generated while building the package.)

[!WARNING] JaCoP uses JavaCall which requires launching Julia with JULIA_NUM_THREADS=1 JULIA_COPY_STACKS=1 julia on MaxOS and Linux. See here for Windows.

Use with JuMP

To use JaCoP with JuMP, use JaCoP.Optimizer:

using JuMP, JaCoP
model = Model(JaCoP.Optimizer)

[!WARNING] There is a known issue where JaCoP.jl segfaults if you delete variables or constraints.

[!TIP] If you experience segfaults (e.g., on Julia 1.12.6+), try adding -Xss2m to increase the JVM thread stack size before initializing JavaCall:

JavaCall.addOpts("-Xss2m")

JaCoP.jl already does this automatically, but if you initialize JavaCall yourself (by passing init_java=false to jacop_java_init), you may need to add this option manually.