From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29086 invoked by alias); 29 Mar 2006 21:08:29 -0000 Received: (qmail 29075 invoked by uid 22791); 29 Mar 2006 21:08:28 -0000 X-Spam-Check-By: sourceware.org Received: from mailwasher.lanl.gov (HELO mailwasher-b.lanl.gov) (192.65.95.54) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 29 Mar 2006 21:08:27 +0000 Received: from alvie-mail.lanl.gov (alvie-mail.lanl.gov [128.165.4.110]) by mailwasher-b.lanl.gov (8.12.11/8.12.11/(ccn-5)) with ESMTP id k2TL8M0P002341 for ; Wed, 29 Mar 2006 14:08:22 -0700 Received: from bellerophon.lanl.gov (bellerophon.lanl.gov [128.165.59.112]) by alvie-mail.lanl.gov (8.12.11/8.12.11/(ccn-5)) with ESMTP id k2TL8KTQ022401; Wed, 29 Mar 2006 14:08:21 -0700 Subject: Re: gsl_linalg_exponential_ss() From: Gerard Jungman To: Tino Kluge Cc: gsl-discuss In-Reply-To: <20060327121954.GA28592@localhost> References: <20060327121954.GA28592@localhost> Content-Type: text/plain Date: Wed, 29 Mar 2006 21:08:00 -0000 Message-Id: <1143666291.2934.92.camel@bellerophon.lanl.gov> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Mailing-List: contact gsl-discuss-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gsl-discuss-owner@sourceware.org X-SW-Source: 2006-q1/txt/msg00092.txt.bz2 On Mon, 2006-03-27 at 13:19 +0100, Tino Kluge wrote: > Hi > > First, many thanks for implementing matrix exponentiation into gsl! > I was just wondering whether there's a way to speed up computation > when faced with matrix exponentials of the form > > exp(t A) > > for many different real values t and one constant matrix A? > > Cheers > Tino If the ratios of the values (t_0, t_1, ...) are integers, then you can get them all by taking matrix powers. An obvious example is the case that the values (t_0, t_1, ...) are regularly spaced, like t_n = n dt. But otherwise I don't know any tricks. Maybe I'm missing something clever though. -- Gerard Jungman Los Alamos National Laboratory