Free Open-Source Solvers for AMPL

Run AMPL models with freely available solvers developed at universities and research centers under open-source licenses.

Use AMPL FREE with open source solvers

Our Community Edition license allows you to use a full-powered AMPL license with no limitations on variables or constraints, free forever, with all open source solvers. Your download in the portal, and have all solvers downloaded to your computer.

Start with an uploaded model, run and modify, or create your own with the AMPL in Google Colab. Open source solvers are already connected. Call them and solve!

Linear & Quadratic Solvers

Powerful options for continuous and integer problems when speed can be compromised or smaller, simple projects.

The COIN Branch and Cut solver (CBC) is an open-source mixed-integer program (MIP) solver written in C++. CBC is intended to be used primarily as a callable library to create customized branch-and-cut solvers. A basic, stand-alone executable version is also available. CBC is an active open-source project led by John Forrest at www.coin-or.org.

HiGHS is open-source software to solve linear programming, mixed-integer programming, and convex quadratic programming models. Written in C++ and published under an MIT license, HiGHS provides programming interfaces to C, Python, Julia, Rust, JavaScript, Fortran, and C#. It has no external dependencies.

Nonlinear Solvers

Your free alternatives for problems involving smooth nonlinear functions of powers, logs, and ratios with the most effectiveness in smaller problem sizes. 

Ipopt (Interior Point Optimizer, pronounced “Eye-Pea-Opt”) is an open source software package for large-scale nonlinear optimization. The Ipopt package is available from COIN-OR under the EPL (Eclipse Public License) open-source license and includes the source code for Ipopt. 

Bonmin is an experimental open-source C++ code for solving general MINLP problems. 

Couenne

This page provides resources for Couenne (Convex Over and Under ENvelopes for Nonlinear Estimation), an Open Source branch&bound algorithm for solving Mixed-Integer Nonlinear Programming (MINLP) problems. Couenne aims at finding global optima of nonconvex MINLPs. It implements linearization, bound reduction, and branching methods within a Branch&Bound framework.

Global Solvers

Handle constraint programming* problems in discrete variables with support of a wide variety of constraint types that may contain nonlinear and logical expressions. 

* Constraint programming solvers can be more effective than MIP solvers for some kinds of combinatorial optimization problems.

Gecode is an open source C++ toolkit for developing constraint-based systems and applications. Gecode provides a constraint solver with state-of-the-art performance while being modular and extensible. Learn more here.

JaCoP is a constraint solver for constraint satisfaction problems. Its main focus is on ease of use, modeling power, as well as efficiency. It has a large collection of global constraints implemented to facilitate problem modeling. Learn more here.

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Linear & Quadratic Solvers

These solvers all handle linear optimization problems in both continuous and integer variables. Their performance is not at the level of analogous commercial solvers, but can be sufficient for problems that are not too large or difficult.

CBC

2.10.5 – From COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux64-bit LinuxOS X32-bit Windows and 64-bit Windows.

HiGHS

 

Nonlinear Solvers

The solvers in this category seek solutions to problems involving smooth nonlinear functions such as powers, logs, and ratios. They differ in the algorithms that they offer, and hence in their effectiveness for different problem types. Due to the difficulty of nonlinear optimization, these solvers are effective with smaller problems than their linear counterparts.

Ipopt 

3.12.13 — From COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux64-bit Linux, macOS X32-bit Windows and 64-bit Windows. Finds locally optimal solutions to continuous nonlinear problems, using an interior-point method.

Bonmin 

1.8.8 — from COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux64-bit LinuxmacOS X32-bit Windows and 64-bit Windows. Finds globally optimal solutions to convex nonlinear problems in continuous and discrete variables, and may be applied heuristically to nonconvex problems.

Couenne 

0.5.8 — from COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux64-bit LinuxmacOS X32-bit Windows and 64-bit Windows. Finds globally optimal solutions to nonlinear problems in continuous and discrete varia

Global Solvers

These solvers handle constraint programming problems usually in discrete variables. They support a wide variety of constraint types that may contain nonlinear and logical expressions. Constraint programming solvers can be more efficient than MIP solvers for some kinds of combinatorial optimization problems.

Gecode

Under the MIT license; available as source code and binaries for 32-bit Linux64-bit LinuxmacOS X32-bit Windows and 64-bit Windows.

JaCoP 

Under the GNU Affero General Public License; available as source code and binaries for 32-bit Linux64-bit LinuxmacOS X32-bit Windows and 64-bit Windows.

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Start today free in the Community Edition and use open source solvers and AMPL free, full-sized, forever. Explore our documentation, learning materials and online support.