I pointed out to Richard Hennessy that it is a mistake to declare xx to be a
symbol.
It is a parameter to the pattern match.
Any time you get a message about matching + or * from defmatch or tellsimp,
it
means you have an ineffective pattern program, probably related to
matchdeclare.
RJF
> -----Original Message-----
> From: maxima-bounces at math.utexas.edu
> [mailto:maxima-bounces at math.utexas.edu] On Behalf Of Robert Dodier
> Sent: Saturday, October 25, 2008 8:46 PM
> To: Richard Hennessy
> Cc: Maxima List
> Subject: Re: [Maxima] tellsimp problem
>
> On 10/25/08, Richard Hennessy <rvh2007 at comcast.net> wrote:
>
> > (%i5) integrate(unit_step(7*x+9),x);
> > Improper value assignment:xx*aa -- an error. To debug
> this try debugmode(true);
>
> Rich, that looks like a bug in the tellsimp code -- can you please
> make a bug report?
>
> Matching + and * expressions is kind of tricky --- I tried a
> few variations
> on the problem you stated and couldn't make any headway.
>
> best
>
> Robert Dodier
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