[Maxima] -inf vs. minf, tex(), web interface updates

[Robert Dodier]

Matthew,

> I'm wondering why "-inf" behaves differently from "minf."

I don't know if there's any explanation. There is an open bug report
(http://sourceforge.net/tracker/index.php?func=detail&aid=820188&group_id=4933&atid=104933)
in which the author (Stavros) suggests getting rid of minf and
representing negative infinity by - inf throughout.

> Is there a way, in Maxima, to make "-inf" evaluate to "minf"?

Try this:

tellsimp (- inf, minf);  /* recognize simplified - 1 * foo */
tellsimp (- minf, inf);
simp : false;
tellsimp (- inf, minf);  /* recognize unsimplified minus(foo) */
tellsimp (- minf, inf);
simp : true;
:lisp (setq $rules '((mlist)))

These rules tell the Maxima simplifier to substitute minf for - inf
and inf for - minf. I think that's very much preferable to doing it by hand
(e.g. string substitution or expression substitution on input and/or output).

The last bit about clobbering the rules list is a heavy-handed way
to prevent kill(all) from killing the inf/minf rules.

run_testsuite is pretty happy with these rules; the only failed tests
are ones for which und (undefined) is expected and the result is - und.

> I'd also encourage you to check out my Web interface, since I've made
> significant progress in the last few weeks. New features include:

Looks really, really nice. Only thing that I notice is that the last cell on the
page is usually partly obscured (and maybe completely obscured,
if the preceding output is tall enough). Seems like there should be a
way to cause the scroll bar to scroll all the way down automatically.

Also there doesn't seem to be a way to restart the session.
Reloading the page seems to continue the old session.

On the whole the web interface is really impressive. Keep up the good work!

Robert Dodier