From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20322 invoked by alias); 23 Jul 2002 20:08:47 -0000 Mailing-List: contact gsl-discuss-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gsl-discuss-owner@sources.redhat.com Received: (qmail 20312 invoked from network); 23 Jul 2002 20:08:45 -0000 Received: from unknown (HELO relay1.decf.berkeley.edu) (169.229.204.213) by sources.redhat.com with SMTP; 23 Jul 2002 20:08:45 -0000 Received: from relay1.decf.berkeley.edu (localhost [127.0.0.1]) by relay1.decf.berkeley.edu (8.11.6/8.11.6) with ESMTP id g6NK8jM22360 for ; Tue, 23 Jul 2002 13:08:45 -0700 (PDT) Received: from maxwell.berkeley.edu (maxwell.Berkeley.EDU [169.229.204.204]) by relay1.decf.berkeley.edu (8.11.6/8.11.6) with ESMTP id g6NK8dk22327 for ; Tue, 23 Jul 2002 13:08:44 -0700 (PDT) Received: from DMA-Tosh2000.me.berkeley.edu (dean102.COE.Berkeley.EDU [128.32.196.154]) by maxwell.berkeley.edu (8.11.6/8.11.6) with ESMTP id g6NK8WB06595 for ; Tue, 23 Jul 2002 13:08:33 -0700 Message-Id: <5.1.0.14.2.20020723125836.01b66578@maxwell.berkeley.edu> X-Sender: dma@maxwell.berkeley.edu (Unverified) Date: Tue, 23 Jul 2002 13:08:00 -0000 To: gsl-discuss@sources.redhat.com From: Dave Auslander Subject: Error scaling in ODE-IV Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-SW-Source: 2002-q3/txt/msg00086.txt.bz2 I am using the ODE-initial value routines from GSL. In looking at section 24.3 or the GSL manual, I note that there does not appear to be any scaling array for the error calculation in the adaptive algorithms. eps_rel and eps_abs are scalars. Most ODE systems, however, are not naturally scaled so all components have the same scale so it is very difficult to optimize performance. Am I missing something or is this the intended usage? Thanks Dave Auslander PS - many thanks to the GSL developers. This is a huge, very useful effort. +++++++++++++++++++++++++++++++++++++++++++++++ David M. Auslander, Prof. of ME and Assoc. Dean Mechanical Engineering, Univ of Calif, Berkeley, CA 94720-1740 Dean's office: 510-642-7594 ME: 510-642-4930 Fax: 510-643-5599 dma@me.berkeley.edu www.me.berkeley.edu/~dma +++++++++++++++++++++++++++++++++++++++++++++++