Completing all kinds of numeric calculations is possible thanks to FreeMat. This software is specially focused on science, engineering and data processing, being a fully-fledged alternative to other similar programs that are better known in this field, like MATLAB.
Open-source alternative to MATLAB
FreeMat is an open-source program developed under the GPL license and therefore is totally free, something that can't be said about the majority of similar programs. Its programming language is as similar as possible to that of MATLAB, thus offering the possibility to use developments that have been created for that application with it. Furthermore, it also accepts external code in other languages like C, C++...
Furthermore, the interface of FreeMat accepts code in other languages and allows you to view the projects in 3D. It also offers support for parallel computation algorithms by means of MPI.
If you're looking for a numerical calculation environment you can download FreeMat, the free alternative to MATLAB capable of offering a very similar features without having to pay.