AMPL Forum

AMPL Solvers

AMPL supports the most popular and powerful optimization engines.

Whereas AMPL creates optimization problems from models and data, and retrieves results for analysis, solvers are the number-crunching algorithms that compute optimal solutions.

The AMPL product does not incorporate solvers, but rather provides interfaces to the products of competing solver developers. Thus to apply AMPL in your work, you will need to obtain at least one solver having an AMPL interface. We make it easy by offering a broad selection of AMPL-enabled solvers directly from our download portal.

Main kinds of solvers

Your first step in choosing a solver will be to determine which ones are applicable to the optimization problems that derive from your application. There are three broad classes of solvers to consider:

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Linear & Quadratic Solvers

Solvers in this category are the most widely used for diverse applications throughout business, government, and research organizations.

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Nonlinear Solvers

Nonlinear solvers are used extensively in applications such as energy transmission and engineering design that have a physical component, and in advanced economic and financial modeling.

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Global Solvers

These solvers combine a variety of approaches to handle optimization problems that are difficult due to multiple locally optimal solutions, nonsmooth and discrete functions, and/or highly combinatorial or logical constraints.

Choosing solvers

Although many solvers rely on common overall approaches to optimization, each individual solver’s design is based on its own complex mix of algorithmic ideas and implementation strategies. Thus solver performance cannot readily be predicted from problem size or other simple measures. Rather, solve times and memory requirements are best evaluated through tests on problems typical of your application.

AMPL Community Edition

Get free access to full-featured AMPL and open-source solvers, with no limitations on size of problem for personal, academic and commercial prototyping use. Optionally add 30-day trials of powerful solvers that we sell.

30-Day Full Trial

Get a full-featured trial package of AMPL and all the solvers that we sell, good for 30 days.

Acquiring solvers to use with AMPL

We offer the best and most popular solvers, with new ones frequently added.

Buy from us

To provide the fastest run times and greatest reliability, we offer a selection of top commercial solvers interfaced to AMPL. We provide the same high level of licensing and technical support for these solvers as for the core AMPL product.

Download free solvers

AMPL interfaces are included with a number of popular solvers distributed under open-source licenses. We provide links to pre compiled executables so that you can set up these free solvers quickly for use with AMPL.

Acquire solvers directly from developers.

Our full list of AMPL-interfaced solvers includes a variety of alternatives that may meet your needs.

More ways to use solvers with AMPL

NEOS Server

NEOS is an online service providing free access to over 30 solvers that work with AMPL. Many NEOS solvers are conveniently accessed directly from an AMPL session, by use of Kestrel, a special solver-like application that we provide. Alternatively, AMPL model and data files can be uploaded through the NEOS website, with results returned by email.

Hooking Your Solver to AMPL

Two open, documented interface libraries are available for hooking AMPL to any solver that your are developing. The widely used “ASL” is a collection of C routines that provide solvers with linear and quadratic coefficient lists and efficiently compute nonlinear function values plus first and second derivatives. The newer “mp” is a C++ class library that extends the power of AMPL by recognizing and transforming a broad variety of model functions and expressions. Both are based on the flexible “nl” format for optimization problems.

Ready to get started?

Explore our licenses and offerings or create an account to get started right away. You can also contact us to design the right solution to meet your business needs.