Scilab is a scientific software package for numerical computations in a
user-friendly environment.

Main features
    * Hundreds of mathematical functions
    * High level programming language
    * 2-D and 3-D graphics
    * Advanced data structures and user defined data types
    * Xcos: hybrid dynamic systems modeler and simulator
2-D and 3-D visualization
    * Lines
    * Pie charts
    * Histograms
    * Surfaces
    * Animations
    * Graphics export in many formats: GIF, BMP, JPEG, SVG, PDF...
Numerical computation
    * Linear algebra
    * Sparse matrices
    * Polynomials and rational functions
    * Simulation: explicit and implicit systems of differential
      equations solvers
    * Classic and robust control
    * Differentiable and non-differentiable optimization
Data analysis
    * Interpolation, approximation
    * Signal Processing
    * Statistics
Extended features
    * Graphs and Networks
    * Interface with Fortran, C, C++, Java
    * Functions for calling Scilab from C, C++, Fortran and Java
    * LabVIEW Gateway
    * A large number of modules available via ATOMS

WWW: http://www.scilab.org