GNU Octave is a high-level language, primarily intended for numerical computations. It provides a convenient command line interface for solving linear and nonlinear problems numerically, and for performing other numerical experiments using a language that is mostly compatible with Matlab.
D. Lucrédio, R. de M. Fortes, E. de Almeida, and S. Meira. High Confidence Software Reuse in Large Systems, volume 5030 of Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, (2008)