Metalinguistic Abstraction

Computer Languages, Programming, and Free Software

SAGE Computer Algebra System

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While skimming the RSS feed for Lambda the Ultimate I spied an entry about a functional definition of TeX’s formula typesetting algorithm. For me the real gem here was not some insight about TeX, but a solitary (at the time of this writing) comment about the CAS SAGE (and its integration with jsMath). SAGE is pretty interesting, but we’ll get to why it’s interesting in a moment after discussing some other well known CAS and scientific computation programs.

I have never understood some people’s obsession with Matlab, Mathematica, and similar tools. I mean, I kind of do: they are allegedly well designed tools, the former providing well-optimized versions of just about every well known numerical recipe you want. Matlab was popular with the EE guys in college for plotting and numerical methods, and I know that the Mathematica guys can do some impressive symbolic manipulation and interactive visualization with relatively minimal effort…

But something feels wrong. It’s not just a matter of the proprietary nature of these tools, although that and the high price can sometimes be most…dissuading. Especially when the pricing information is hidden after a login screen, or one of the first calls to action is to request a quote. One knows that they are not in for a good time under these circumstances, generally speaking. But projects like GNU Octave also set off my radar, even though it has low cost. Why?

The real answer is the “tool among tools[0]” philosophy. This is also possibly the main reason why Lisp lost out to C and UNIX, as well as the relative obscurity of Smalltalk, despite its alleged brilliance (it is not something I have used myself). Part of this is cultural (GNU Octave: a scientific computation system mostly compatible with MATLAB, nowhere in the mission is high levels of integration) and part can be more sinister motivation (MATLAB has a negative incentive to ease transition to Mathematica and vice versa). Mathworks and Wolfram are both given incentive to instead make their own platform as attractive as possible and trying to one-up everyone else instead of wasting time making sure that everyone can move their codes around: the latter is just not good business.

Enter SAGE. This package is shamelessly and unabashedly about integration, much in the Python philosophy. In fact it’s written in Python with liberal FFI bindings using the most excellent Pyrex extension language and compiler. It has unidirectional bindings to an impressive number of CAS systems (including many I have never heard of) with some basic parsing/data type normalization. And, most importantly, it avoids the problem of getting yourself locked into a particular CAS with no hope for escape[1].

For me personally it may be useful for plotting; I still typically write my actual math codes in C (maybe Lisp for prototyping, but that’s another post). I will have to take a look. I hope that in the future that they may gain some interoperability with statistical tools such as SAS and R (which already has a Python integration package that, alas, only works on Python 2.4), as I think this would only increase the leverage of this tool tremendously. One hopes that the proprietary vendors won’t take offense and start trying to break things, ala Microsoft. If things get even better then maybe they’ll pay due notice and at least try to avoid breaking things all the time. At best, they’ll start to feature SAGE (or similar system) interoperability as a feature, and the world may be better off.

Footnotes:
[0]: I first heard this phrasing from Guido van Rossum when he gave a talk at Berkeley.
[1]: As detailed by another blogger, who also gives a different take and overview of SAGE. Actually, his is a lot more detailed in just about every respect, so I’d highly recommend reading this if you are seriously interested.

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Written by fdr

June 28, 2007 at 1:51 am

Posted in mathematics

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