From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: John Darrington Newsgroups: gmane.lisp.guile.user Subject: Re: Can somebody help to explain why result from atan does not equal a real? Date: Thu, 31 Jan 2013 15:50:17 +0100 Message-ID: <20130131145017.GA27085@jocasta.intra> References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Qxx1br4bt0+wmkIi" X-Trace: ger.gmane.org 1359643838 4396 80.91.229.3 (31 Jan 2013 14:50:38 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 31 Jan 2013 14:50:38 +0000 (UTC) Cc: Guile Mailing List To: Noah Lavine Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Thu Jan 31 15:50:57 2013 Return-path: Envelope-to: guile-user@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1U0vTd-0001Ft-Gb for guile-user@m.gmane.org; Thu, 31 Jan 2013 15:50:57 +0100 Original-Received: from localhost ([::1]:35260 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U0vTL-0003ue-G2 for guile-user@m.gmane.org; Thu, 31 Jan 2013 09:50:39 -0500 Original-Received: from eggs.gnu.org ([208.118.235.92]:44455) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U0vTC-0003uL-AP for guile-user@gnu.org; Thu, 31 Jan 2013 09:50:35 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U0vT7-0004LL-GD for guile-user@gnu.org; Thu, 31 Jan 2013 09:50:30 -0500 Original-Received: from de.cellform.com ([88.217.224.109]:39347 helo=jocasta.intra) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U0vT7-0004L4-3l for guile-user@gnu.org; Thu, 31 Jan 2013 09:50:25 -0500 Original-Received: from jocasta.intra (localhost [127.0.0.1]) by jocasta.intra (8.14.3/8.14.3/Debian-9.4) with ESMTP id r0VEoH7L027208 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Thu, 31 Jan 2013 15:50:18 +0100 Original-Received: (from john@localhost) by jocasta.intra (8.14.3/8.14.3/Submit) id r0VEoHsV027206; Thu, 31 Jan 2013 15:50:17 +0100 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 88.217.224.109 X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Original-Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.user:9954 Archived-At: --Qxx1br4bt0+wmkIi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 31, 2013 at 08:32:53AM -0500, Noah Lavine wrote: What you have here is a precision problem. =20 scheme@(guile-user)> (=3D 3.14159265358979 (atan 0 -1)) $8 =3D #f scheme@(guile-user)> (=3D $7 (atan 0 -1)) $9 =3D #t =20 It might be possible to have Guile print more digits and make this pro= blem go away. =20 Noah Lavine pi is an irrational number. You would need an infinite number of digits wo= uldn't you? --=20 PGP Public key ID: 1024D/2DE827B3=20 fingerprint =3D 8797 A26D 0854 2EAB 0285 A290 8A67 719C 2DE8 27B3 See http://keys.gnupg.net or any PGP keyserver for public key. --Qxx1br4bt0+wmkIi Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAlEKhKkACgkQimdxnC3oJ7OuGwCeIGwLsEJCJVTqExqvVorxXFAH +/kAoINwl7uR6rsgmsaKCUzazQr6VjFv =xxZ8 -----END PGP SIGNATURE----- --Qxx1br4bt0+wmkIi--