Frequently Asked Questions

1. Do I need to be able to program in Rust?

No. Although the core solver is written in Rust, you can generate code in Python or MATLAB and use it from Python. You can also use the auto-generated C/C++ bindings to use it in your embedded project.

Even if you are working in a Rust project, it is more convenient to generate Rust code using OpEn's Python interface and then use the auto-generated code in your project.

If your project is in some different language, you can either use the C/C++ bindings (if possible), or call the solver over a TCP socket (supported by all modern programming languages).

2. Can OpEn find the global optimum?

No. OpEn does not offer any guarantees that the solution it returns is a global optimum.

3. Can OpEn solve mixed integer problems?

Yes. OpEn solves parametric problems of the form

\[\begin{split}\mathbb{P}(p) {}:{} \operatorname*{Minimize}_{u {}\in{} \mathbb{R}^{n_u}}&\ \ f(u, p)\\ \mathrm{subject\ to}\ \ &u \in U\\ & F_1(u, p) \in C\\ & F_2(u, p) = 0\end{split}\]

Set $U$ can be a finite or binary set (on which it is easy to compute projections).

4. Can OpEn solve multi-objective problems?

No.

5. How should I choose the L-BFGS memory?

A value between 3 and 20 should suffice, although the performance is not too sensitive to the exact value of the L-BFGS memory. You shouldn't choose too high values as this will increase the memory requirements of your program (esp. for large-scale problems) and might have a negative effect on performance.

Long story short... if you need very high performance, you should experiment with it. Otherwise, stick with any value between 3 and 20.

6. How can I cite OpEn?

See this page

7. Does it work on all operating systems?

Yes. We have tested the code on Linux (Trusty, Precise and Xenial), OSX Darwin and Windows x32 adn x64 using Travis CI and Appveyor reprectively. We have also cross-compiled the Rust solver and tested it on a Raspberry Pi v2 (ARM v6 processor).

8. I have a question; whom should I address it to?

You can reach us on Discord and Gitter.

Find out more information here.

9. How can I report an issue?

Please report any issues on github.

10. Is OpEn being actively developed

Yes, we are constantly exploring extensions, adding new features and addressing issues that our users report on github. See some statistics about OpEn below: