Return-Path: X-Original-To: apmail-commons-dev-archive@www.apache.org Delivered-To: apmail-commons-dev-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id DFB8583E8 for ; Wed, 7 Sep 2011 10:46:26 +0000 (UTC) Received: (qmail 17684 invoked by uid 500); 7 Sep 2011 10:46:25 -0000 Delivered-To: apmail-commons-dev-archive@commons.apache.org Received: (qmail 17397 invoked by uid 500); 7 Sep 2011 10:46:22 -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 17156 invoked by uid 99); 7 Sep 2011 10:46:15 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 07 Sep 2011 10:46:15 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: local policy) Received: from [193.74.71.26] (HELO hel.is.scarlet.be) (193.74.71.26) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 07 Sep 2011 10:46:08 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=scarlet.be; s=scarlet; t=1315392347; bh=GuCLSk3CwUTqx36MhRmrjWgUebfytP3eurGULjJ/SSM=; h=Date:From:To:Subject:Message-ID:MIME-Version:Content-Type; b=V4rlOm0aWUpwPSSEZm1tPsHrDjRGkzyvulNrWfC5PuY8oe+KFX7qQu0sg7hgiY7U6 DGPNJ18zUEHZ+LWCD6uX7gXVxZVT/dWSabhKo3JFWcxXkQExKGcfjwyjBqxqZ8jHuK 9t0T3UT/5NLicwyjLn/Tt+5r4x2poNcKe9mXsmfo= Received: from mail.harfang.homelinux.org (ip-62-235-230-191.dsl.scarlet.be [62.235.230.191]) by hel.is.scarlet.be (8.14.5/8.14.5) with ESMTP id p87Ajkq1028387 for ; Wed, 7 Sep 2011 12:45:46 +0200 X-Scarlet: d=1315392346 c=62.235.230.191 Received: from localhost (mail.harfang.homelinux.org [192.168.20.11]) by mail.harfang.homelinux.org (Postfix) with ESMTP id 1ADC561CE9 for ; Wed, 7 Sep 2011 12:45:46 +0200 (CEST) Received: from mail.harfang.homelinux.org ([192.168.20.11]) by localhost (mail.harfang.homelinux.org [192.168.20.11]) (amavisd-new, port 10024) with ESMTP id Yq85SfPnzehE for ; Wed, 7 Sep 2011 12:45:44 +0200 (CEST) Received: from dusk.harfang.homelinux.org (mail.harfang.homelinux.org [192.168.20.11]) by mail.harfang.homelinux.org (Postfix) with ESMTP id 5AF8D6175F for ; Wed, 7 Sep 2011 12:45:44 +0200 (CEST) Received: from eran by dusk.harfang.homelinux.org with local (Exim 4.76) (envelope-from ) id 1R1FdY-0001Hp-4X for dev@commons.apache.org; Wed, 07 Sep 2011 12:45:44 +0200 Date: Wed, 7 Sep 2011 12:45:43 +0200 From: Gilles Sadowski To: dev@commons.apache.org Subject: [Math] "LUDecomposition" in "AbstractLeastSquaresOptimizer" Message-ID: <20110907104543.GR2590@dusk.harfang.homelinux.org> Mail-Followup-To: dev@commons.apache.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Operating-System: Tiny Tux X-PGP-Key-Fingerprint: 53B9 972E C2E6 B93C BEAD 7092 09E6 AF46 51D0 5641 User-Agent: Mutt/1.5.21 (2010-09-15) X-DCC-scarlet.be-Metrics: hel 20002; Body=1 Fuz1=1 Fuz2=1 X-Virus-Scanned: clamav-milter 0.97.1-exp at hel X-Virus-Status: Clean Hello. In class "AbstractLeastSquaresOptimizer" (in "o.a.c.m.optimization.general"), the method "getCovariances()" uses "LUDecompositionImpl" to compute the inverse of a matrix. In my application, this leads to a "SingularMatrixException". If I change "LUDecompositionImpl" to "QRDecompositionImpl", no exception is raised. Also, keeping "LUDecompositionImpl" but passing a much lower singularity threshold, does not raise the exception either. Thus, I wonder whether there was a reason for using "LU", and if not, whether I could change the decomposition solver to "QR" (as this is a cleaner solution than guessing a good value for the threshold). Regards, Gilles --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org For additional commands, e-mail: dev-help@commons.apache.org