From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23753 invoked by alias); 1 Jul 2010 21:32:19 -0000 Received: (qmail 23740 invoked by uid 22791); 1 Jul 2010 21:32:18 -0000 X-SWARE-Spam-Status: No, hits=-1.9 required=5.0 tests=BAYES_00 X-Spam-Check-By: sourceware.org Received: from mx.freeshell.org (HELO sdf.lonestar.org) (192.94.73.19) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 01 Jul 2010 21:32:15 +0000 Received: from sdf.lonestar.org (IDENT:jstover@sdf.lonestar.org [192.94.73.15]) by sdf.lonestar.org (8.14.4/8.14.3) with ESMTP id o61LWDH1015415; Thu, 1 Jul 2010 21:32:13 GMT Received: (from jstover@localhost) by sdf.lonestar.org (8.14.4/8.12.8/Submit) id o61LWCvS001202; Thu, 1 Jul 2010 21:32:12 GMT Date: Thu, 01 Jul 2010 21:32:00 -0000 From: Jason Stover To: Jonathan Leto Cc: gsl-discuss@sourceware.org, "Laskin, Nick" Subject: Re: Calculating the square root of n?n positive-semidefinite real matrix A Message-ID: <20100701213212.GB13367@SDF.LONESTAR.ORG> Reply-To: jason@sakla.net References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) 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: 2010-q3/txt/msg00001.txt.bz2 On Thu, Jul 01, 2010 at 01:24:06PM -0700, Jonathan Leto wrote: > I maintain the Math::GSL CPAN [0] module and recently a user asked me > how to calculate the square root of a n?n positive-semidefinite real > matrix A. I browsed > through the GSL documentation and did not immediately find anything. > Is there a way to do this currently with GSL? The user is asking about a matrix factorization, probably Cholesky. See the linear algebra section of the GSL manual, including gsl_linalg_cholesky_decomp. -- jstover@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org