[Maxima] possible bug with integration of unit_step

Valery Pipin pip at iszf.irk.ru
Wed Dec 17 07:22:41 CST 2008


On Wednesday 17 December 2008 20:34:31 Barton Willis wrote:
> 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
>
>
> _______________________________________________
> Maxima mailing list
> Maxima at math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima
On ALTLinux I've get: 
[va at shiva-225 SPECS]$ rmaxima                                                                               
STYLE-WARNING:                                                                                              
   redefining ASDF:PERFORM :AROUND (#<STANDARD-CLASS ASDF:LOAD-OP>
                                    #<STANDARD-CLASS ASDF:CL-SOURCE-FILE>) in 
DEFMETHOD
Maxima 5.17.1 http://maxima.sourceforge.net
Using Lisp SBCL 1.0.23
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1)  display2d : false$

(%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) 'integrate(x*cos(x^2)+unit_step(x),x)
(%i3) integrate(unit_step(x),x);

(%o3) 'integrate(unit_step(x),x)



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