From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5717 invoked by alias); 3 Dec 2003 14:25:34 -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 5708 invoked from network); 3 Dec 2003 14:25:33 -0000 Received: from unknown (HELO smtp0.libero.it) (193.70.192.33) by sources.redhat.com with SMTP; 3 Dec 2003 14:25:33 -0000 Received: from libero.it (193.70.192.43) by smtp0.libero.it (7.0.020-DD01) id 3F6F1CE3008FD2D3; Wed, 3 Dec 2003 15:25:33 +0100 Date: Wed, 03 Dec 2003 14:25:00 -0000 Message-Id: Subject: Root function MIME-Version: 1.0 X-Sensitivity: 3 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable From: "lauradiara\@libero\.it" To: "gsl-discuss" To: "help-gsl help-gsl" X-XaM3-API-Version: 4.1 (B19) X-type: 0 X-SenderIP: 193.76.233.91 X-SW-Source: 2003-q4/txt/msg00112.txt.bz2 Hi, I'd like to write a function which finds all the roots of a funcion y=3Df(x) provided by the user. I have read the chapter one dimensional root finding: I have some questions. The concept expressed is that you use root bracketing or root polishing: wi= th the first you have to provide an initial intervalwitha root inside, while w= ith the second you have to provide a guess root. The first question is: both metods find only a root: if the function has mo= re roots what happen? The second question is that the initial condition (guess or interval with a root) is not simple, it's difficult to provide a good value. All the examples are quite simple with a function provided athe start and n= ot inserted by the user: so the guess or the interval is simple. But in the re= al applications, what can you do? I think there is a solution, otherwise the functions in gsl_roots,h are not usable in real situations. Can you give me some advice? Thanks --Laura