Noteworthy Differences from other Languages

If you are new to the Julia programming language, you are encouraged to visit the documentation page on noteworthy differences between Julia and other programming languages.

The rest of this page will list noteworthy differences between ControlSystems.jl and other pieces of control-systems software.

• Functions to calculate poles and zeros of systems are named using their plural forms, i.e., poles instead of pole, and tzeros instead of tzero.
• Simulation using lsim, step, impulse returns arrays where time is in the second dimension rather than in the first dimension (applies also to freqresp, bode, nyquist etc.). Julia uses a column major memory layout, and this choice is made for performance reasons.
• Functions are, lqr and kalman have slightly different signatures in julia compared to in other languages. More advanced LQG functionalities are located in RobustAndOptimalControl.jl.
• Simulation using lsim, step, impulse etc. return a structure that can be plotted. These functions never plot anything themselves.
• Functions bode, nyquist etc. never produce a plot. Instead, see bodeplot, nyquistplot etc.
• In Julia, functionality is often split up into several different packages. You may therefore have to install and use additional packages in order to cover all your needs. See Ecosystem for a collection of control-related packages.
• In Julia, 1 has a different type than 1.0, and the types in ControlSystemsBase.jl respect the types chosen by the user. As an example, tf(1, [1, 1]) is a transfer function with integer coefficients, while tf(1.0, [1, 1]) will promote all coefficients to Float64.
• Julia treats matrices and vectors as different types, in particular, column vectors and row vectors are not interchangeable.
• In Julia, code can often be differentiated using automatic differentiation. When using ControlSystems.jl, we recommend trying ForwardDiff.jl for AD. An example making use of this is available in Automatic Differentiation.
• In Julia, the source code is often very readable. If you want to learn how a function is implemented, you may find the macros @edit or @less useful to locate the source code.
• If you run into an issue (bug) with a Julia package, you can share this issue (bug report) on the package's github page and it will often be fixed promptly. To open an issue with ControlSystems.jl, click here. Thank you for helping out improving open-source software!
• Julia compiles code just before it is called the first time. This introduces a noticeable lag the first time a function is called, and can make packages take a while to load.

If you find other noteworthy differences between ControlSystems.jl and other pieces of control-related software, please consider opening an issue on the github repository.