Return-Path: Delivered-To: apmail-commons-dev-archive@www.apache.org Received: (qmail 91897 invoked from network); 26 Mar 2010 21:44:20 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 26 Mar 2010 21:44:20 -0000 Received: (qmail 80791 invoked by uid 500); 26 Mar 2010 21:44:20 -0000 Delivered-To: apmail-commons-dev-archive@commons.apache.org Received: (qmail 80702 invoked by uid 500); 26 Mar 2010 21:44:20 -0000 Mailing-List: contact dev-help@commons.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: "Commons Developers List" Delivered-To: mailing list dev@commons.apache.org Received: (qmail 80694 invoked by uid 99); 26 Mar 2010 21:44:20 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 26 Mar 2010 21:44:20 +0000 X-ASF-Spam-Status: No, hits=-2.3 required=10.0 tests=RCVD_IN_DNSWL_MED,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [164.15.128.112] (HELO mxin.ulb.ac.be) (164.15.128.112) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 26 Mar 2010 21:44:12 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAC6+rEukD30x/2dsb2JhbACbKnO/NwKEfASOGA Received: from astropc8.ulb.ac.be ([164.15.125.49]) by smtp.ulb.ac.be with ESMTP; 26 Mar 2010 22:43:52 +0100 Date: Fri, 26 Mar 2010 22:43:52 +0100 (CET) From: Dimitri Pourbaix X-X-Sender: pourbaix@astropc8.ulb.ac.be To: Commons Developers List , johnsonb@umbc.edu Subject: Re: Math Release 2.1 SVD In-Reply-To: <58584.173.54.27.123.1269627407.squirrel@webmail.umbc.edu> Message-ID: References: <58584.173.54.27.123.1269627407.squirrel@webmail.umbc.edu> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Checked: Checked by ClamAV on apache.org Bruce, > > The 2.1 API docs for the Singular Value Decomposition say: > > The size p depends on the chosen algorithm: > > for full SVD, p is n, > for compact SVD, p is the rank r of the matrix (i. e. the number of > positive singular values), > for truncated SVD p is min(r, t) where t is user-specified. > > > but I don't see any method or constructor to specify whether to do the > full, compact or truncated SVD. Am I missing something, or is the code > missing something? The doc is not synchronized with the source, I apologize (but the javadoc should be). The code offers only one version which is none of the above! From the Java file: The Singular Value Decomposition of matrix A is a set of three matrices: U, Σ and V such that A = U × Σ × V^T. Let A be a m × n matrix, then U is a m × p orthogonal matrix, Σ is a p × p diagonal matrix with positive or null elements, V is a p × n orthogonal matrix (hence V^T is also orthogonal) where p=min(m,n). Dim. ---------------------------------------------------------------------------- Dimitri Pourbaix * Institut d'Astronomie et d'Astrophysique * Don't worry, be happy CP 226, office 2.N4.211, building NO * and CARPE DIEM. Universite Libre de Bruxelles * Boulevard du Triomphe * Tel : +32-2-650.35.71 B-1050 Bruxelles * Fax : +32-2-650.42.26 http://sb9.astro.ulb.ac.be/~pourbaix * mailto:pourbaix@astro.ulb.ac.be --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org For additional commands, e-mail: dev-help@commons.apache.org