[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Octave-bug-tracker] [bug #48307] sinc loses precision for large argumen
From: |
Colin Macdonald |
Subject: |
[Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments |
Date: |
Tue, 5 Jul 2016 04:14:17 +0000 (UTC) |
User-agent: |
Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:47.0) Gecko/20100101 Firefox/47.0 |
Follow-up Comment #22, bug #48307 (project octave):
> the lack of precision in the input, which is insurmountable.
Careful here. I've said several times that is *not a given* that sinc must be
computed using the formula sin(x)/x. One could search for an asymptotic
expansion for example in large x, or maybe do a contour integral with
quadrature in the complex plane. The we use sin(x)/x for smallish x and
switch to that something else for large x. Although I have not found anyone
who does this yet (Matlab and SciPy both seem to just evaluate sin(x)/x like
we do for example).
> So I'm assuming Maple is using long double math.
No, Maple is using arbitrary precision arithmetic. (Generally to slow for
core Octave, although Symbolic pkg will do this if a user needs it).
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?48307>
_______________________________________________
Message sent via/by Savannah
http://savannah.gnu.org/
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, (continued)
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Colin Macdonald, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Lachlan Andrew, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Colin Macdonald, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Dan Sebald, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Lachlan Andrew, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Marco Caliari, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Marco Caliari, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Dan Sebald, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Lachlan Andrew, 2016/07/04
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Dan Sebald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments,
Colin Macdonald <=
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Colin Macdonald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Colin Macdonald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Lachlan Andrew, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Dan Sebald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Dan Sebald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Colin Macdonald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Marco Caliari, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Dan Sebald, 2016/07/05
- [Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments, Colin Macdonald, 2016/07/06