From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1QaeAz-0002BO-30 for garchives@archives.gentoo.org; Sun, 26 Jun 2011 01:30:17 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 06F0E1C00C; Sun, 26 Jun 2011 01:28:59 +0000 (UTC) Received: from qmta09.emeryville.ca.mail.comcast.net (qmta09.emeryville.ca.mail.comcast.net [76.96.30.96]) by pigeon.gentoo.org (Postfix) with ESMTP id B32D71C00C for ; Sun, 26 Jun 2011 01:28:59 +0000 (UTC) Received: from omta22.emeryville.ca.mail.comcast.net ([76.96.30.89]) by qmta09.emeryville.ca.mail.comcast.net with comcast id 0RSH1h0061vN32cA9RUxtV; Sun, 26 Jun 2011 01:28:57 +0000 Received: from ajax ([24.11.47.14]) by omta22.emeryville.ca.mail.comcast.net with comcast id 0RUi1h0020JMh7c8iRUi6d; Sun, 26 Jun 2011 01:28:44 +0000 Date: Sat, 25 Jun 2011 21:28:56 -0400 From: Frank Peters To: gentoo-amd64@lists.gentoo.org Subject: Re: [gentoo-amd64] Possible Math Problem - Request For Verification Message-Id: <20110625212856.b565b9da.frank.peters@comcast.net> In-Reply-To: <20110626015453.4a67fe37@marcec.huntemann.uni-oldenburg.de> References: <20110625134111.5c6b08dd.frank.peters@comcast.net> <20110626015453.4a67fe37@marcec.huntemann.uni-oldenburg.de> X-Mailer: Sylpheed 3.1.1 (GTK+ 2.24.5; x86_64-unknown-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-amd64@lists.gentoo.org Reply-to: gentoo-amd64@lists.gentoo.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Archives-Salt: X-Archives-Hash: f1c804631fa2397b5e5fede6ce38a42c On Sun, 26 Jun 2011 01:54:53 +0200 Marc Joliet wrote: > > Then according to the results above my machine is apparently OK. (I guess I > really should finally read about IEEE floating point more thoroughly, I've been > planning to do that for a while now.) > These tests are extreme. The accuracy is supposedly less than 1 ulp (unit in the last place). You can check the *output files in the results directory to see more information on the error. For example, the COS(X) error file is ccos_DP.output and contains the maximum positive and maximum negative errors in ulps. On my machine these are 1.567 and -3.74 ulps, so the error is small. In contrast, the LOG(X) function passes the test but it still shows errors of 0.532 and -0.531 ulps. Frank Peters