From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gsl-discuss-return-5611-listarch-gsl-discuss=sources.redhat.com@sourceware.org>
Received: (qmail 30153 invoked by alias); 6 Feb 2010 15:26:14 -0000
Received: (qmail 30136 invoked by uid 22791); 6 Feb 2010 15:26:13 -0000
X-SWARE-Spam-Status: No, hits=-0.6 required=5.0
	tests=AWL,BAYES_20,SARE_MSGID_LONG40,SPF_PASS
X-Spam-Check-By: sourceware.org
Received: from mail-bw0-f221.google.com (HELO mail-bw0-f221.google.com) (209.85.218.221)
    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 06 Feb 2010 15:26:10 +0000
Received: by bwz21 with SMTP id 21so4023005bwz.4
        for <gsl-discuss@sourceware.org>; Sat, 06 Feb 2010 07:26:07 -0800 (PST)
MIME-Version: 1.0
Received: by 10.204.30.214 with SMTP id v22mr1599992bkc.136.1265469967438; 
	Sat, 06 Feb 2010 07:26:07 -0800 (PST)
In-Reply-To: <87ljh0nqp4.wl%bjg@network-theory.co.uk>
References: <4a00655d0908201247g7d7bd9a1t466f4a66f08df4@mail.gmail.com> 
	<4a00655d0911291538y9f29830v984d1a796fdd5d1@mail.gmail.com> 
	<m34ooa7qvr.wl%bjg@network-theory.co.uk> <4a00655d0912131549w19638273nb51d723e9ddd9273@mail.gmail.com> 
	<87d42ggnsv.wl%bjg@network-theory.co.uk> <4a00655d0912150931q4b34fd24p94594ed08857254f@mail.gmail.com> 
	<87zl5ig7i0.wl%bjg@network-theory.co.uk> <4a00655d0912161643k63868ac4i2577f618f6e2196@mail.gmail.com> 
	<87zl5hnrkh.wl%bjg@network-theory.co.uk> <87ljh0nqp4.wl%bjg@network-theory.co.uk>
From: Rhys Ulerich <rhys.ulerich@gmail.com>
Date: Sat, 06 Feb 2010 15:26:00 -0000
Message-ID: <4a00655d1002060725q21794722n12f69160c26e381a@mail.gmail.com>
Subject: Re: Where a generalized Richardson extrapolation routine would fit in 
	GSL?
To: Brian Gough <bjg@gnu.org>
Cc: gsl-discuss@sourceware.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
Mailing-List: contact gsl-discuss-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gsl-discuss.sourceware.org>
List-Subscribe: <mailto:gsl-discuss-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gsl-discuss/>
List-Post: <mailto:gsl-discuss@sourceware.org>
List-Help: <mailto:gsl-discuss-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gsl-discuss-owner@sourceware.org
X-SW-Source: 2010-q1/txt/msg00015.txt.bz2

Sorry for the long hiatus on this Richardson extrapolation thread:

> I think the best interface would be the analog of the existing levin
> sum routines:
>
> ...
>
> int gsl_extrap_richardson (const double *array,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 const size_t n,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 const double t,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 const size_t k
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 gsl_extrap_richardson=
_workspace * w,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 double *result, doubl=
e *abserr);
>
> It would be useful to have both a result and abserr, to take into
> account cancellation error.

I'm good on moving the interface away from gsl_matrix and gsl_vector.
No problem there.  But, from looking a bit at the levin sum
documentation, I'm not sure how to apply the abserr concept to
Richardson extrapolation.  Any guidance would be much appreciated.

Brian, if this is an easier thing to talk through on the phone and
you're willing to do so, please contact me directly.

- Rhys