MATLAB
Commercial
MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programming language.
R (programming language)
Open Source
R is an open source programming language and software environment for statistical computing and graphics that is supported by the R Foundation.
Sage
Open Source
Sage offers business management, bookkeeping & accounting software to meet any business need, from small to midsized businesses.
python(x,y)
Open Source
Python(x,y) is a free scientific and engineering development software for numerical computations, data analysis and data visualization based on Python.
Spyder
Open Source
Spyder is the Scientific PYthon Development EnviRonment: a powerful interactive development environment for the Python language with advanced editing.
GNU Octave
Open Source
GNU Octave is a programming language for scientific computing.
Mathematica
Commercial
Wolfram Mathematica (usually termed Mathematica, Mathematica software suite) is a mathematical symbolic computation program.
SciPy & Numpy
Open Source
NumPy and SciPy are open-source add-on modules to Python that provide common mathematical and numerical routines in pre-compiled, fast functions.
Julia
Open Source
Julia is a high-level, high-performance dynamic programming language for numerical computing.
Freemat
Open Source
FreeMat is a free environment for rapid engineering and scientific prototyping and data processing.
Compare Scilab with alternatives
Compare R (programming language) and Scilab and decide which is most suitable for you.
Compare SciPy & Numpy and Scilab and decide which is most suitable for you.