[Maxima] Strange Bug(?)
macrakis at alum.mit.edu
Fri Apr 18 10:43:40 CDT 2008
I don't know what the problem is in your calculation, but I wonder if
it has to do with Maxima's treatment of inf and minf, which
unfortunately are treated just like other symbolic constants (like
%pi), so inf-inf = 0, which is of course incorrect.
Normally this wouldn't matter, since Maxima doesn't generate inf and
minf during expression manipulation, but with simpsum = true, it does,
so you get things like
sum(1,i,1,inf) - sum(2,i,1,inf) => 0
which is of course nonsense.
Try the following inf-safe sum definition and see what happens:
Let us know.
PS I think there's a good argument to be made for having Maxima do
something similar with inf/minf it generates, making each one
distinct. I know that someone (Raymond?) is also working on having
the simplifier not do inf-inf=>0, but there are lots of places other
than the general simplifier which need to be changed (rat
representation, compare, etc.).
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