Subject: possible bug with integration of unit_step
From: Barton Willis
Date: Wed, 17 Dec 2008 06:34:31 -0600
Here is a bug I found using Maxima CVS + SBCL 1.0.22 + XP. I know that
SBCL + XP is experimental--is this problem unique to SBCL + Windows?
$ ./maxima-local
This is experimental prerelease support for the Windows platform: use
at your own risk. "Your Kitten of Death awaits!"
Maxima 5.16post http://maxima.sourceforge.net
Using Lisp SBCL 1.0.22
(%i1) display2d : false$
Not OK:
(%i2) integrate(x * cos(x^2) + unit_step(x),x);
STYLE-WARNING: redefining SIMP-UNIT-STEP in DEFUN
STYLE-WARNING: redefining SIMP-POCHHAMMER in DEFUN
(%o2) sin(x^2)/2
(%i3) integrate(unit_step(x),x);
OK:
(%o3) 'integrate(unit_step(x),x)
(%o3) 'integrate(unit_step(x),x)
Some of you know that I have a bit of code for integrands of the form
p(x) * |q(x)|, p(x) * unit_step(q(x)), ... where q(x) is a product of
linear factors. The bug in (%o2) isn't related to my (what will be
share/contrib) code, (I didn't load my code). Using 5.17.0 + GLC + XP, I
get a
nounform for (%o2).
Barton