HELP needed: Taylor bugs



PS.  it would be nice to know what is supposed to be
done here.  There are various other programs like $ratexpand
that expand polynomials.  Or is it not really a polynomial?
RJF

Martin RUBEY wrote:
> I just submitted two fixes for a trivial and an easy taylor bug I found. 
> Unfortunately, the ONE taylor bug I tried to fix I couldn't, but I have
> a clue now:
> 
> taylor(sum(M^K*sum(L^K,L,1,D),K,1,INF),M,0,2),simpsum;
> 
> gives a nearly correct answer, only the L's should be replaced by D's...
> 
> 
> It appears that the error occurs when fpolysum in combin.lisp is called.
> fpolysum in turn is
> 
> (defun fpolysum (e)     ;returns *ans*
>    (let ((a (fpoly1 (setq e ($expand ($ratdisrep ($rat e *var*))))))
> 
> and within the ratdisrep rat stuff the following happens:
> 
> usually a rat expression is
> 
>  ((MRAT SIMP <varlist> <genvar> <tlist> trunc) <poly-form>)
> 
> where varlist and genvar have the same length.
> 
> Here they don't, quite on the contrary, genvar contains quite some rubbish 
> I do not REALLY understand where it could come from.
> 
> My question is:
> 
> should varlist and genvar really always have the same length or is this 
> not required?
> 
> where should I look to now?
> 
> Martin
> 
> _______________________________________________
> Maxima mailing list
> Maxima@www.math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima