Scilab

Scilab is a scientific software package for numerical computations in a user-friendly environment. It features: Elaborate data structures (polynomial, rational and string matrices, lists, multivariable linear systems,…). Sophisticated interpreter and programming language with Matlab-like syntax. Hundreds of built-in math functions (new primitives can easily be added). Stunning graphics (2d, 3d, animation). Open structure (easy interfacing with Fortran and C via online dynamic link). Many built-in libraries: Linear Algebra (including sparse matrices, Kronecker form, ordered Schur,…). Control (Classical, LQG, H-infinity,…). Package for LMI (Linear Matrix Inequalities) optimization. Signal processing. Simulation (various ode’s, dassl,…). Optimization (differentiable and non-differentiable, LQ solver). Scicos, an interactive environment for modeling and simulation of dynamical systems. Metanet (network analysis and optimization). Symbolic capabilities through Maple interface. Parallel Scilab.
Find Scilab at: http://www.scilab.org/