Bfloat allroots



Modeling Maxima's bigfloats as a separate package would make it more 
plausible to
drop in an alternative, especially MPFR, at some future stage, into Maxima.
I would prefer that MPFR be callable from within Maxima, rather than 
looking to
outside control. E.g.   Sage would presumably look at a problem
and try to decide between MPFR and Maxima, making Maxima appear to be,
and in fact, less capable than Sage in this respect [assuming MPFR is 
"better" than what the 2 or 3 people
here have done with bfloats, and that MPFR will be pushed further by 
others.]

I thought we had better root-finding in the FORTRAN routines. There is a 
Laguerre
method that is supposedly better than Jenkins-Traub.  Converting that to 
lisp bfloats
might be good. (In fact, I think I have a Laguerre method written in 
Lisp from first
principles, but it was done by a student who didn't totally inspire 
confidence.)

Good luck.

RJF






Robert Dodier wrote:
> On 12/12/08, Raymond Toy <raymond.toy at ericsson.com> wrote:
>
>   
>>  Perhaps this can be placed in cpoly.lisp or maybe as a contrib in
>>  share/numeric.
>>     
>
> Since it 's a bigfloat version of an existing algorithm,
> I would put it in the same place as the existing one.
>
>   
>>  Also, I should probably also convert rpoly-sl to support bfloats, and
>>  then allroots and bfallroots will be functionally identical.
>>     
>
> OK by me.
>
> best
>
> Robert
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