We know there is a range of solvers, with both free and paid options, that you can choose from.

We also know that for some situations, a free (open source) solver might be all that you need. But how do you know if a free solver is good enough for your decision problems? When is a free solver sufficient, and when should you lean on a commercial solver like Gurobi?

Here, we’ll explore free solvers, what they do well, how they compare to Gurobi, and some questions to ask yourself in deciding what type of solver is right for you.

Open-Source Solvers: An Overview

One of the best things about open-source solvers is that they lower the barrier to entry for optimization. With no licensing costs, it’s relatively easy to get started right away.

Whether you're a student, a developer building a prototype, or a business team exploring optimization for the first time, open-source tools can help you take those crucial first steps.

These solvers can be quite effective for smaller, less complex models, or for users with strong technical skills. But as your needs grow, you may start to run into limitations—especially in performance, scalability, and support.

When Open Source Might Be Enough

There are many valid reasons to choose a free solver. For example, you might choose the open-source route if:

1. There is no approved budget.
   Often, when a company is first looking at using an optimization solver in their business, there may not be an approved budget. Management may still be trying to determine the role optimization can play in planning and decision-making, and the team doing the work is still “getting their feet wet.”

2. Your models are both small and relatively easy to solve.
   For straightforward models without many constraints and variables, open-source solvers can perform well.

3. The available APIs and features are sufficient for your needs.
   Open-source solvers typically are less feature-complete and may not provide full APIs for several programming languages.

   
   

But even if all three points above apply to your situation, it’s important to think ahead. If your model will eventually grow in size or complexity—or if you’ll need faster solve times, robust support, or more flexibility—it may be wise to start with a solver that can grow with you.

What If Open-Source Fails?

One of the most important questions people tend to ask when they are first exploring solvers is if optimization is a fit for their business. We have seen cases where someone selected a free solver, tried building a model, and the solver just couldn’t handle the problem. As a result, they assumed their problem was too complex to use optimization techniques.

Others may find free solvers too difficult to use—perhaps it wasn’t compatible with their preferred programming language, didn’t offer adequate support, or could not resolve issues and bugs in a timely fashion. The team then ends the project and moves on. This is unfortunate since, with the right tools and support, the project might have been a great success.

Scaling Up with Gurobi

• As your optimization challenges become more complex, a commercial solver like Gurobi can help you go further—and faster. Here's why:

• Exceptional performance: Gurobi is consistently ranked as the fastest solver across a wide range of problem types, from LP and MIP to QCP and MIQCP.

• Global optimality: Gurobi isn’t just the fastest solver on the market; it can solve a wide range of problems to global optimality, meaning that it can identify the best solution amongst all possibilities.

• Robust and reliable: Gurobi delivers dependable results, even for the toughest problems. You can rest assured that the code won’t break, and each year will bring a new release with key updates and improvements.

• Broad language compatibility: Gurobi offers APIs for Python, C/C++, Java, .NET, MATLAB, and R.

• World-class support: With a commercial Gurobi license, you get access to our team of PhD-level optimization experts, who are ready and waiting to answer your questions, help you tune your model, and ensure a seamless experience with our solver.

• Academic users get Gurobi for free: If you're a student, faculty member, or academic researcher, Gurobi is available at no cost through our full-featured academic license.

• To compare the performance of Gurobi vs. open-source solvers, particularly for energy planning problems, check out the Open Energy Benchmark by Open Energy Transition.

Should I Start with Open-Source Tools and Switch to a Commercial Tool Later?

Open-source tools can make it easy to get started with optimization, but you should approach them with your eyes open. For example, if an open-source tool is unable to solve your model, you shouldn’t assume that your project is hopeless.

A state-of-the-art commercial solver like Gurobi can save valuable development time in several ways. First, the interfaces are typically more polished and advanced than those in open-source tools (for example, the Gurobi Python interface brings a modeling syntax to the popular Python language). In addition, Gurobi also offers pre-built IT infrastructure, like client-server options and cloud computing.

Try Gurobi for Free

Unlike open-source solvers, Gurobi does charge license and maintenance fees. But before you make your decision, why not try Gurobi yourself—for free?

When you request a Gurobi evaluation license, our team will work closely with you to create a plan for the evaluation period. Depending on your focus area and current stage of model development, this might include providing a license to do benchmarking on your existing model, or facilitating a collaborative trial with our Optimization Experts, who can do performance tuning for you.

Whatever stage you’re in, we’ll work with you to make sure you can scale your usage and maximize the value you get from Gurobi.

Ready to get started? Learn more or request your free evaluation license today.