From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13415 invoked by alias); 20 Nov 2001 08:58:09 -0000 Mailing-List: contact gsl-discuss-help@sourceware.cygnus.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gsl-discuss-owner@sources.redhat.com Received: (qmail 13391 invoked from network); 20 Nov 2001 08:58:05 -0000 Received: from unknown (HELO omecihuatl.rz.uni-osnabrueck.de) (131.173.17.35) by sourceware.cygnus.com with SMTP; 20 Nov 2001 08:58:05 -0000 Received: from 0 (kalliope.rz.Uni-Osnabrueck.DE [131.173.17.44]) by omecihuatl.rz.uni-osnabrueck.de (8.11.1/8.11.1) with ESMTP id fAK8w4f10486 for ; Tue, 20 Nov 2001 09:58:04 +0100 Message-ID: <200111200858.fAK8w4f10486@omecihuatl.rz.uni-osnabrueck.de> Subject: Nonlinear Least Squares Fitting Date: Fri, 16 Nov 2001 10:53:00 -0000 From: Andreas Gros Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=iso-8859-1 To: gsl-discuss@sources.redhat.com User-Agent: IMHO/0.98.2 (Webmail for Roxen) MIME-Version: 1.0 X-SW-Source: 2001-q4/txt/msg00043.txt.bz2 Message-ID: <20011116105300.G7liahsRy8MlZyWv5HJ4OAQO-IHS6WeTdr-PIK9Ekl4@z> Hello, I'd like to submit a "bug" in the solver: gsl_multifit_fdfsolver_lmsder. In the section "Providing the function to be minimized" where the function gsl_multifit_function_fdf is described, you mention the function f that should store the distance between the values calculated by the algorithm and the provided values. As I tested the algorithm I've found, that this distance is not taken as a "square", instead the algebraic sign of the distance seems to be of some importance. My results were quite different, whenever I took (y[i]-Yi) instead of (Yi-y[i]) (as it is shown in the example). Taking the latter the solver works fine, taking the first distance the results have been quite funny. Andreas Gros Andreas Gros, Tel.: 0179-1062416 Lotter Str. 99, 49078 Osnabrück Amalienstr. 8, 97072 Würzburg http://www.gros-webdesign.de