I'm using the sage-5.5 command line and some variables are automatically declared. For instance I can do
f = x^2but not
f = t^2My question: How does this come about? Which variables are defined like this? Where is this documented?
See sage/all.py and sage/all_cmdline.py in the devel/sage directory. In addition to x, we define oo to be infinity, e to be the base of the natural log, i to be a certain root of x2−1=0, ZZ to be the integers, and some other things - and of course lots and lots of functions.
You could also do `globals()` to find everything at all, but I don't think that is what you meant.
Interesting effect: Type "globals()" in a session where you have done 'a few' plots before.
First I was not convinced since in sage/all.py the line defining x is commented out (both, in your linked version and in the file on my disk), but then I saw that it comes from the line "from sage.calculus.predefined import x" in all_cmdline.py. Thanks.
Asked: 12 years ago
Seen: 303 times
Last updated: Jan 03 '13
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