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 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.
CBC
The COIN Branch and Cut solver (CBC) is an open-source mixed-integer program (MIP) solver written in C++. CBC is an active open-source project led by John Forrest at www.coin-or.org.
HiGHS
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
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
Bonmin is an experimental open-source C++ code for solving general MINLP problems.
Global Solvers
Global optimization in the presence of multiple locally optimal solutions. Techniques for nonsmooth and discrete functions, and for highly combinatorial and/or logical constraints.
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.
Constraint 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
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.
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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.
2.10.5 – From COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux, 64-bit Linux, OS X, 32-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.
3.12.13 — From COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux, 64-bit Linux, macOS X, 32-bit Windows and 64-bit Windows. Finds locally optimal solutions to continuous nonlinear problems, using an interior-point method.
1.8.8 — from COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux, 64-bit Linux, macOS X, 32-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.
0.5.8 — from COIN-OR under the Eclipse Public License; available as source code and binaries for 32-bit Linux, 64-bit Linux, macOS X, 32-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.
Under the MIT license; available as source code and binaries for 32-bit Linux, 64-bit Linux, macOS X, 32-bit Windows and 64-bit Windows.
Under the GNU Affero General Public License; available as source code and binaries for 32-bit Linux, 64-bit Linux, macOS X, 32-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.