Sage is a free open source symbolic and numerical mathematics software which is programmed in Python. Like Python which comes with batteries included, Sage comes with “matheries” included and is bundled with a host of math and visualization packages - jmol - java 3d molecule viewer, R and much more which can be invoked by importing. The goal is to be a viable alternative to Mathematica and Maple and it also has support for interaction and animation.
The co-creators also point to the need to enable transparency in mathematical research, that you can inspect the PDE solver or factorization into primes. This is completely opaque in Mathematica. There is also support for getting web data see example 2 and 3 which fetches data from NOAA and does an regression analysis on the time interval you choose. The second example fetches arctic ice data and plot for the month you choose. Sage has a lot of very fast time series support
Sage tutorial is the best way to get started with SAGE
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