Subject: Work on the complex components: abs, carg, ...
From: Dieter Kaiser
Date: Fri, 1 May 2009 22:53:25 +0200
I have stayed a week in Texas and New Mexico and now I am back in Germany. I
prepare to commit the extensions for the complex components.
Yes, the handling of zeros for the functions carg and atan2 has to be thought
through. Now, carg(0) simplifies to zero, but atan2(0,0) generates an error. The
simplification for carg(0) is not correct, because carg(0) is undefined.
Furthermore we have to think about the global flag ABSFLAG, which seems to cause
bugs in the routine trisplit.
Dieter Kaiser
-----Urspr?ngliche Nachricht-----
Von: robert.dodier at gmail.com [mailto:robert.dodier at gmail.com]
Gesendet: Dienstag, 28. April 2009 05:50
An: Dieter Kaiser
Cc: maxima at math.utexas.edu
Betreff: Re: [Maxima] Work on the complex components: abs, carg, ...
On 4/23/09, Dieter Kaiser <drdieterkaiser at web.de> wrote:
> atan2 does not recognize that abs(x) is a positive (or zero) value.
I'd like to see something like assert(abs(x) > 0 if x # 0, abs(0) = 0)
i.e. declarations which directly state conditions in which some
predicate is satisfied. Something to think about.
I;m in agreement with the proposed changes.
Thanks a lot and keep up the good work!
Robert Dodier