Subject: Warning usng facsum to factor specific terms
From: Robert Dodier
Date: Mon, 5 Dec 2005 07:24:21 -0700
On 12/5/05, Julian Swartz wrote:
> (%i44) facsum(a*b+b*c+a*c, a);
> Warning - you are redefining the MACSYMA function INTERSECTION
> (%o44) A (C + B) + B C
>
> Why does maxima issue this warning and
> should I be concerned about it at all?
The facsum code is in an add-on package which is loaded
on demand. This add-on defines a number of functions,
one of which is "intersection" which is also defined in the
main source code. Presumably when facsum was
written (circa 1980) there was no "intersection" yet.
The redefinition is harmful only if you later call intersection
and expect to get the built-in function.
The two are probably similar but I'd be surprised if they
were identical.
A good project would be for someone to trawl through
the add-on packages looking for redefinitions of
built-in functions.
Thanks for your interest in Maxima, & hope this helps.
Robert Dodier