Scilab description: Scientific software package for numerical computations. Scilab is a matrix-based scientific software package. Scilab contains hundreds of built-in mathematical functions, rich data structures (including polynomials, rationals, linear systems, lists, etc…), and comes with a number of specific toolboxes for control, signal processing, etc. This package also provides Xcos, a graphical editor to design hybrid dynamic systems models. Models can be designed, loaded, saved, compiled and simulated. A stable and efficient solution for industrial and academic needs, Xcos provides functions for modelling of mechanical systems (automotive, aeronautics…), hydraulic circuits (dam, pipe modelling…), control systems, etc. Modelica capabilities are also provided. I am totally blown away with the features available in Scilab, in my opinion rivalling Matlab, and definitely ahead of Octave (Octave's new GUI should be released soon).

With any piece of software, the first thing I try to do is use the software to see how easy it is to use. Then I'll look at the help section to see how to do the things I want to do. If that does not suffice, I'll look at the documentation. On ease of use, Scilab is as simple to use as a calculator. Just type in a calculation and press enter. Scilab can also do more involved mathematics such as finding the roots of polynomials. Just search in the help section for roots. There is an example script that can either be viewed and executed from Scinotes (Scilab's text editor) or directly in Scilab.

There is a plethora of online documentation, online tutorials and websites available. A great website I used for control systems is Scilab Ninja. The Scilab for beginners guide, available from the Scilab Enterprises website, is also excellent. By far my favourite part of Scilab is Xcos – the model diagram editor. It is Scilab's version of Mathworks Simulink. It can model a number of systems from control engineering, to electric circuits and physical systems. The feature I found most useful is that Xcos can be integrated into Scilab scripts written in Scinotes to run model diagram simulations with given parameters. To get a feel of what Scilab is capable of there is a demonstrations feature. There are many demos and it seems more will be added in the future.

Pros: • Lots of features • It’s free • Easy to use • Excellent help section and demonstrations • Includes Xcos Xcos doubles as a circuit simulator Cons: • Scilab crashes if you press enter without entering data • Xcos crashes Scilab if block diagrams are given unknown references

Conclusion Scilab is truly a marvel of free software engineering. I did not even begin to scratch the surface of the usefulness of Scilab for mathematics, engineering and physics. This software can and should be used in high-schools and universities. Scilab is far easier to learn and start using than Octave. Scilab is one of those software programs that makes you go wow! I can't believe this is free. The occasional crash is the only thing costing Scilab a perfect review. I'm sure within the next release these minor issues will be sorted out.