I'm sure the overhead is tiny, but you are also calculating f' in each
iteration.
On 9/5/07, Robert Bradshaw <[EMAIL PROTECTED]> wrote:
>
>
> On Sep 5, 2007, at 1:25 PM, John Voight wrote:
>
> > Wow Robert, thanks! Talk about real-time recreating the wheel--my
> > code is quite similar, though I
On Sep 5, 2007, at 1:25 PM, John Voight wrote:
> Wow Robert, thanks! Talk about real-time recreating the wheel--my
> code is quite similar, though I was using floats.
Well, it was pretty quick to write, and I was curious as to the
accuracy it would give. I wrote an mpfr-based root refiner too
Wow Robert, thanks! Talk about real-time recreating the wheel--my
code is quite similar, though I was using floats.
Three questions for ya:
(1) Is there a reason to use Py_ssize_t instead of int or even
unsigned int? If it's for length, I can't imagine we'd have
polynomials of that huge a degr
Try the code below--it is very fast and should give you enough
precision as long as you know it to enough precision for convergence
the root you're looking for is not to large.
- Robert
On Sep 4, 2007, at 9:35 AM, John Voight wrote:
>
> Hello Carl,
>
>> As Robert Bradshaw mentioned, I did
On Sep 4, 9:35 am, "John Voight" <[EMAIL PROTECTED]> wrote:
> In my situation, I have the following absurdly easy case: I have a
> real interval in which I know there is exactly one real root which I
> need to know to maybe 6 or 10 digits of precision. The polynomials
> are monic, have small inte
Hello Carl,
> As Robert Bradshaw mentioned, I did spend a lot of time working on
> real root isolation; unfortunately, I have not yet found the time to
> polish it off and contribute it to SAGE (although I'm still planning
> to!).
>
> What do you need for real root finding for your problem? In
>
On Sep 3, 10:43 am, John Voight <[EMAIL PROTECTED]> wrote:
> (2) Real root finding predominates the computation. I was hoping that
> numpy would do this the fastest--but now it seems to be giving erratic
> results (see http://trac.sagemath.org/sage_trac/ticket/583). It may
> turn out that most o
Hey John,
I'm happy to hear that you're using some number field stuff in SAGE.
As Robert mentioned in his post (and I think it was on sage-devel),
there are a few of us looking at getting this in much better shape in
the near future. In light of that, please keep telling us things you
wish
I know Carl Witty spent a lot of time doing work on real root
isolation--perhaps you could take a look at his Algebraic Reals code
(sage/rings/algebraic_real.py)
Algebraic number theory is something that a lot of us want to focus
on improving in the very near term.
- Robert
On Sep 3, 2007
