octave

GNU Octave is a high-level interpreted language, primarily intended for
numerical computations. It provides capabilities for the numerical
solution of linear and nonlinear problems, and for performing other
numerical experiments. It also provides extensive graphics capabilities
for data visualization and manipulation. Octave is normally used through
its interactive command line interface, but it can also be used to write
non-interactive programs. The Octave language is quite similar to
Matlab so that most programs are easily portable.