From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30236 invoked by alias); 4 Jun 2009 18:52:00 -0000 Received: (qmail 30227 invoked by uid 22791); 4 Jun 2009 18:51:59 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from smtp4.welho.com (HELO smtp4.welho.com) (213.243.153.38) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 04 Jun 2009 18:51:53 +0000 Received: from [10.0.0.133] (cs78197013.pp.htv.fi [62.78.197.13]) by smtp4.welho.com (Postfix) with ESMTP id 81D3B5BC04C; Thu, 4 Jun 2009 21:51:50 +0300 (EEST) Message-ID: <4A28180A.2030103@iki.fi> Date: Thu, 04 Jun 2009 18:52:00 -0000 From: Tuomo Keskitalo User-Agent: Mozilla-Thunderbird 2.0.0.19 (X11/20090103) MIME-Version: 1.0 To: Rhys Ulerich CC: Brian Gough , gsl-discuss@sourceware.org Subject: Re: Implementing hybrid explicit/implicit ODE stepper References: <4a00655d0906030731l8632674o9abb33dca522e689@mail.gmail.com> <4A28028B.8020403@iki.fi> <4a00655d0906041040y135755cdlc877ba570c4308da@mail.gmail.com> In-Reply-To: <4a00655d0906041040y135755cdlc877ba570c4308da@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Mailing-List: contact gsl-discuss-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gsl-discuss-owner@sourceware.org X-SW-Source: 2009-q2/txt/msg00014.txt.bz2 On 06/04/2009 08:40 PM, Rhys Ulerich wrote: > This integrator tends to get used in DNS of Navier-Stokes since the > memory savings become significant for very large fields. Ok, now I understand a bit more. I don't think the current GSL ode-initval is directly suitable for that kind of specialized problem. The framework does not support separation of f(u) into two components. You would first have to make changes to gsl_odeiv_system to provide that, and then modify all the rest accordingly. Might be doable, I don't know. Would your application benefit from step size control, or evolution functionality similar to those in ode-initval? If yes, then you might try to start from ode-initval and modify it. Otherwise I suggest you look for how others have designed these kinds of solvers and then create a new framework suitable for this kind of a problem. Of course, if you end up implementing only that one stepper, you can use code snippets from ode-initval for it. Regards, Tuomo -- Tuomo.Keskitalo@iki.fi http://iki.fi/tuomo.keskitalo