### Sage

Sage is a free open-source mathematics software system licensed under the GPL. It combines the power of many existing open-source packages into a common Python-based...

- it is free. It combines the abilities of many open source systems. The user interface is fairly simple and easy to learn.
- Excellent alternative to Maple and Mathematica for the serious user ; may alleviate Matlab needs (except for dedicated toolboxes, which may or may not have a Python/Sage equivalent). Users need to invest some time in learning Python and some basics of undergraduate mathematics. Not much shiny interface gadgets, but a trove of mathematical gems. Excellent tools for the production of reproducible research/actie documents. Definitely recommended if openness is important.