From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Jay Belanger Newsgroups: gmane.emacs.bugs Subject: bug#19025: 24.4; precision error when adding two floats Date: Tue, 11 Nov 2014 20:28:49 -0600 Message-ID: <87mw7xtan2.fsf@gmail.com> References: <87oasd6vl4.fsf@gmail.com> Reply-To: jay.p.belanger@gmail.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1415759370 20713 80.91.229.3 (12 Nov 2014 02:29:30 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 12 Nov 2014 02:29:30 +0000 (UTC) To: 19025@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Nov 12 03:29:21 2014 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1XoNgP-0006vV-0A for geb-bug-gnu-emacs@m.gmane.org; Wed, 12 Nov 2014 03:29:21 +0100 Original-Received: from localhost ([::1]:52157 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoNgO-0006LT-6j for geb-bug-gnu-emacs@m.gmane.org; Tue, 11 Nov 2014 21:29:20 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:33013) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoNgD-0006LN-Ue for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:29:17 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoNg6-0007dM-F0 for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:29:09 -0500 Original-Received: from debbugs.gnu.org ([140.186.70.43]:60797) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoNg6-0007d1-BT for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:29:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1XoNg5-0007Qa-S3 for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:29:01 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Jay Belanger Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 12 Nov 2014 02:29:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 19025 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: notabug Original-Received: via spool by 19025-submit@debbugs.gnu.org id=B19025.141575932828514 (code B ref 19025); Wed, 12 Nov 2014 02:29:01 +0000 Original-Received: (at 19025) by debbugs.gnu.org; 12 Nov 2014 02:28:48 +0000 Original-Received: from localhost ([127.0.0.1]:58010 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNfs-0007Pq-1J for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:28:48 -0500 Original-Received: from mail-oi0-f46.google.com ([209.85.218.46]:35696) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNfp-0007Pd-AB for 19025@debbugs.gnu.org; Tue, 11 Nov 2014 21:28:45 -0500 Original-Received: by mail-oi0-f46.google.com with SMTP id g201so7935216oib.19 for <19025@debbugs.gnu.org>; Tue, 11 Nov 2014 18:28:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:subject:references:reply-to:cc:date:in-reply-to:message-id :user-agent:mime-version:content-type; bh=cbc0dfwTGan92a14MV0F1vXrxUHJc1fTYxBCcc24PIU=; b=y5Qtx216KNWPopMhnO0aj8LLlTCbnn1ZYJhtlnfXGGn/sxlfxQMmz6NlCAOqpY4PLe JLSqKcdrmY0qOY/hA9b0PuwACP6jEOrxxZ8Up2G03ZXLteoFu8uNVa6N5kE/Vc3gBKNZ fNojAlp1WBJ95LGiOnEyHgVpslww/EX4e1UifvMYoHjS7GBo0X4G46b//IRWkxyNAY8P ZmaausICZjFYmf0DO3U4uP4GAxEEO2CsFEgnhCyOhvHYuq1K6/N3kjw1Z2qOa4dKcRVz o3nYn0G0pEP5JjjeSenzg9UiYmvVijd9xAF9RbazDHAoj9UmPLK4jDVoQm1gwegLbhdS SqmA== X-Received: by 10.182.20.112 with SMTP id m16mr35439354obe.25.1415759324269; Tue, 11 Nov 2014 18:28:44 -0800 (PST) Original-Received: from belanger-home (184-155-90-233.cpe.cableone.net. [184.155.90.233]) by mx.google.com with ESMTPSA id j8sm8579438oeq.11.2014.11.11.18.28.43 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 11 Nov 2014 18:28:43 -0800 (PST) In-Reply-To: <87oasd6vl4.fsf@gmail.com> (Alexis's message of "Wed, 12 Nov 2014 12:38:12 +1100") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:95896 >> (message "%s" (+ 379.744 57.93)) >> >> The above prints 437.67400000000004. Same if I use 57.930, but if I >> use 57.931 (below) I get the correct answer 437.675. >> >> (message "%s" (+ 379.744 57.931)) >> >> I was able to work around by using format: >> >> (message "%s" (format "%f" (+ 379.744 57.93))) >> >> which prints 437.674000. >> >> FYI, I can replicate the issue with Emacs 21.3.1. > > Isn't this an artifact of the nature of floating-point arithmetic, rather than > an issue with Emacs per se? Yes, although it probably wouldn't be a bad idea to point out this issue in the Elisp documentation.