Adam Majewski wrote:
> Hi
>
> I'm trying to use your program for polynomial given by recurence
> relation ( see: http://fraktal.republika.pl/mset_centers.html);
> My polynomial :
> P(n):=if n=0 then 0 else P(n-1)^2+c;
> List of coefficients:
> give_coefficients(n):=block( P(n):=if n=0 then 0 else P(n-1)^2+c,
> Pn:expand(P(n)), degree:hipow(Pn,c),
> a:makelist(coeff(Pn,c,degree-i),i,0,degree) );
> example of use:
> a:give_coefficients(3);
> (%o7) [1,2,1,1,0]
>
> but :
> polyroots(a);
> does not work.
> What I do wrong?
>
>
Did you get the second e-mail with the new_poly function in it? You
need that. And since the coefficients are rational, the roots will only
have double-float precision. If you want more precision, you need to
convert them to bfloats and set fpprec appropriately.
However, even with that, it doesn't work either. :-( The constant term
is zero, which confuses the algorithm. If you remove that, polyroots
works:
polyroots([1,2,1,1]);
[.7448617666197442 %i - .1225611668766536,
- .7448617666197443 %i - .1225611668766536, -
1.754877666246693]
polyroots needs to be updated. I'll do that soon.
Ray