From unknown Sun Jun 22 03:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#19025: 24.4; precision error when adding two floats Resent-From: "Kevin W. Currey" Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 12 Nov 2014 01:25:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: report 19025 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: 19025@debbugs.gnu.org X-Debbugs-Original-To: "bug-gnu-emacs@gnu.org" Received: via spool by submit@debbugs.gnu.org id=B.141575546214677 (code B ref -1); Wed, 12 Nov 2014 01:25:02 +0000 Received: (at submit) by debbugs.gnu.org; 12 Nov 2014 01:24:22 +0000 Received: from localhost ([127.0.0.1]:57961 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoMfV-0003oe-GU for submit@debbugs.gnu.org; Tue, 11 Nov 2014 20:24:22 -0500 Received: from eggs.gnu.org ([208.118.235.92]:40081) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoLvm-0002QM-Jy for submit@debbugs.gnu.org; Tue, 11 Nov 2014 19:37:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoLvc-0004dx-Ia for submit@debbugs.gnu.org; Tue, 11 Nov 2014 19:37:06 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: *** X-Spam-Status: No, score=3.6 required=5.0 tests=BAYES_50, FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,HTML_MESSAGE, RECEIVED_FROM_WINDOWS_HOST autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:43302) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoLvc-0004dr-F8 for submit@debbugs.gnu.org; Tue, 11 Nov 2014 19:36:56 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41724) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoLvU-0000kf-Qv for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 19:36:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoLvN-0004ac-7H for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 19:36:48 -0500 Received: from blu004-omc1s14.hotmail.com ([65.55.116.25]:58915) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoLvN-0004aN-22 for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 19:36:41 -0500 Received: from BLU173-W24 ([65.55.116.9]) by BLU004-OMC1S14.hotmail.com over TLS secured channel with Microsoft SMTPSVC(7.5.7601.22751); Tue, 11 Nov 2014 16:36:40 -0800 X-TMN: [C+JyY6c02cwC1Epj55I83Rd4doADuzO2] X-Originating-Email: [kevalier68@hotmail.com] Message-ID: Content-Type: multipart/alternative; boundary="_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_" From: "Kevin W. Currey" Date: Tue, 11 Nov 2014 19:36:39 -0500 Importance: Normal MIME-Version: 1.0 X-OriginalArrivalTime: 12 Nov 2014 00:36:40.0364 (UTC) FILETIME=[B996E6C0:01CFFE10] X-detected-operating-system: by eggs.gnu.org: Windows 7 or 8 [fuzzy] X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -3.8 (---) X-Mailman-Approved-At: Tue, 11 Nov 2014 20:24:20 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.8 (---) --_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable (message "%s" (+ 379.744 57.93)) The above prints 437.67400000000004. Same if I use 57.930=2C but if I use = 57.931 (below) I get the correct answer 437.675. =20 (message "%s" (+ 379.744 57.931)) I was able to work around by using format: =20 (message "%s" (format "%f" (+ 379.744 57.93))) which prints 437.674000. =20 FYI=2C I can replicate the issue with Emacs 21.3.1. =20 Thanks=2C -Kevin =20 =20 In GNU Emacs 24.4.1 (x86_64-unknown-cygwin) of 2014-10-21 on desktop-new Windowing system distributor `Microsoft Corp.'=2C version 6.1.7601 Configured using: `configure --srcdir=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/src/emacs-24.4 --prefix=3D/usr --exec-prefix=3D/usr --bindir=3D/usr/bin --sbindir=3D/usr/= sbin --libexecdir=3D/usr/libexec --datadir=3D/usr/share --localstatedir=3D/var --sysconfdir=3D/etc --libdir=3D/usr/lib --datarootdir=3D/usr/share --docdir=3D/usr/share/doc/emacs --htmldir=3D/usr/share/doc/emacs/html -C --with-w32 --without-file-notification --enable-checking 'CFLAGS=3D-ggdb -O2 -pipe -Wimplicit-function-declaration -Og -g3 -fdebug-prefix-map=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/build= =3D/usr/src/debug/emacs-24.4-1 -fdebug-prefix-map=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/src/ema= cs-24.4=3D/usr/src/debug/emacs-24.4-1' CPPFLAGS=3D LDFLAGS=3D' =20 =20 Important settings: value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix =20 =20 Major mode: Fundamental =20 =20 Minor modes in effect: shell-dirtrack-mode: t display-time-mode: t mouse-wheel-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t line-number-mode: t Recent messages: Load-path shadows: None found. =20 =20 Features: (pp shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils info find-func grep tabify sh-script smie executable shell pcomplete compile comint ansi-color ring dabbrev cc-langs cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs arc-mode archive-mode dired-aux ispell apropos dired help-fns help-mode easymenu mule-util server edmacro kmacro cl-loaddefs cl-lib time jka-compr time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process dbusbind w32 multi-tty emacs) =20 =20 Memory information: ((conses 16 145217 10616) (symbols 48 23227 0) (miscs 40 133 446) (strings 32 31064 5702) (string-bytes 1 930985) (vectors 16 15771) (vector-slots 8 452262 7494) (floats 8 82 775) (intervals 56 640 31) (buffers 960 24)) = --_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
(message "%s" (+ 379.744 57.93))=

The above prints 437.67400000000004. =3B Same if I use 57.930= =2C but if I use =3B57.931 (below) I get the correct answer 437.675. =3B
(message "%s" (+ 379.744 57.931))

I was able to work ar= ound by using format:
 =3B
(message "%s" (format "%f" (+ 379.744 = 57.93)))

which prints 437.674000.
 =3B
FYI=2C I can replic= ate the issue with Emacs 21.3.1.
 =3B
Thanks=2C
-Kevin
&nbs= p=3B
 =3B
In GNU Emacs 24.4.1 (x86_64-unknown-cygwin)
 =3B= of 2014-10-21 on desktop-new
Windowing system distributor `Microsoft Cor= p.'=2C version 6.1.7601
Configured using:
 =3B`configure
 = =3B--srcdir=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/src/emacs-24.4<= br> =3B--prefix=3D/usr --exec-prefix=3D/usr --bindir=3D/usr/bin --sbind= ir=3D/usr/sbin
 =3B--libexecdir=3D/usr/libexec --datadir=3D/usr/shar= e --localstatedir=3D/var
 =3B--sysconfdir=3D/etc --libdir=3D/usr/lib= --datarootdir=3D/usr/share
 =3B--docdir=3D/usr/share/doc/emacs --ht= mldir=3D/usr/share/doc/emacs/html -C
 =3B--with-w32 --without-file-n= otification --enable-checking 'CFLAGS=3D-ggdb
 =3B-O2 -pipe -Wimplic= it-function-declaration -Og -g3
 =3B-fdebug-prefix-map=3D/home/kbrow= n/src/cygemacs/emacs-24.4-1.x86_64/build=3D/usr/src/debug/emacs-24.4-1
&= nbsp=3B-fdebug-prefix-map=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/s= rc/emacs-24.4=3D/usr/src/debug/emacs-24.4-1'
 =3BCPPFLAGS=3D LDFLAGS= =3D'
 =3B
 =3B
Important settings:
 =3B value of $L= ANG: en_US.UTF-8
 =3B locale-coding-system: utf-8-unix
 =3B =3B
Major mode: Fundamental
 =3B
 =3B
Minor mode= s in effect:
 =3B shell-dirtrack-mode: t
 =3B display-time-mo= de: t
 =3B mouse-wheel-mode: t
 =3B file-name-shadow-mode: t<= br> =3B global-font-lock-mode: t
 =3B font-lock-mode: t
 = =3B blink-cursor-mode: t
 =3B line-number-mode: t

Recent mess= ages:
Load-path shadows:
None found.
 =3B
 =3B
Featu= res:
(pp shadow sort gnus-util mail-extr emacsbug message format-spec rf= c822
mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailab= brev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-utilmail-prsvr mail-utils info find-func grep tabify sh-script smie
executa= ble shell pcomplete compile comint ansi-color ring dabbrev
cc-langs cc-m= ode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-v= ars cc-defs arc-mode archive-mode dired-aux ispell apropos
dired help-fn= s help-mode easymenu mule-util server edmacro kmacro
cl-loaddefs cl-lib = time jka-compr time-date tooltip electric uniquify
ediff-hook vc-hooks l= isp-float-type mwheel w32-common-fns disp-table
w32-win w32-vars tool-ba= r dnd fontset image regexp-opt fringe
tabulated-list newcomment lisp-mod= e prog-mode register page menu-bar
rfn-eshadow timer select scroll-bar m= ouse jit-lock font-lock syntax
facemenu font-core frame cham georgian ut= f-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese = hebrew greek romanian slovak
czech european ethiopic indian cyrillic chi= nese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer nad= vice loaddefs button
faces cus-face macroexp files text-properties overl= ay sha1 md5 base64
format env code-pages mule custom widget hashtable-pr= int-readable
backquote make-network-process dbusbind w32 multi-tty emacs= )
 =3B
 =3B
Memory information:
((conses 16 145217 1061= 6)
 =3B(symbols 48 23227 0)
 =3B(miscs 40 133 446)
 = =3B(strings 32 31064 5702)
 =3B(string-bytes 1 930985)
 =3B(v= ectors 16 15771)
 =3B(vector-slots 8 452262 7494)
 =3B(floats= 8 82 775)
 =3B(intervals 56 640 31)
 =3B(buffers 960 24))
= --_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_-- From unknown Sun Jun 22 03:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#19025: 24.4; precision error when adding two floats Resent-From: Alexis Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 12 Nov 2014 01:46:02 +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: To: 19025@debbugs.gnu.org X-Debbugs-Original-To: bug-gnu-emacs@gnu.org Received: via spool by submit@debbugs.gnu.org id=B.141575673516671 (code B ref -1); Wed, 12 Nov 2014 01:46:02 +0000 Received: (at submit) by debbugs.gnu.org; 12 Nov 2014 01:45:35 +0000 Received: from localhost ([127.0.0.1]:57969 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoN02-0004Ko-7R for submit@debbugs.gnu.org; Tue, 11 Nov 2014 20:45:35 -0500 Received: from eggs.gnu.org ([208.118.235.92]:52366) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoMzz-0004Kf-I6 for submit@debbugs.gnu.org; Tue, 11 Nov 2014 20:45:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoMzq-0002sh-0T for submit@debbugs.gnu.org; Tue, 11 Nov 2014 20:45:31 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=BAYES_40,FREEMAIL_FROM, T_DKIM_INVALID autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:36121) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoMzp-0002sZ-Tr for submit@debbugs.gnu.org; Tue, 11 Nov 2014 20:45:21 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54013) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoMzg-0007rO-TE for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 20:45:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoMzX-0002c4-TL for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 20:45:12 -0500 Received: from mail-pd0-x231.google.com ([2607:f8b0:400e:c02::231]:47422) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoMzX-0002Z0-Mv for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 20:45:03 -0500 Received: by mail-pd0-f177.google.com with SMTP id v10so11104130pde.22 for ; Tue, 11 Nov 2014 17:45:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=references:from:to:subject:date:in-reply-to:message-id:mime-version :content-type; bh=4aLMmOCUQCPwV40TelK+lOLj9MVhbxJexrL64rEMuWU=; b=TzHjQe7lX62J4OVCZMaOeBbwiSdjRsgyIiGTleCfFqqm0/+i57EGaWm3SfYw+vzbAT fuXqTwJQ6l7KSIeFkNGt/yX4JF3ISmggLN+n7rNT8SmqldZXX80YGlsy3g8qH/amHCEV Tz2TFyr9f//AewFjvOHPI+E31SZtqkHjc2QpR291qykYmH6NSdHuAp5f3nsmMpztlaVa TkM2IinpNe3XxDqoHONJdxyEIIl1v8iVKqkAzi2bB7zV6NURTx7aQG1YeqlaOC4bjP+s LmixH0aCQaRuVgzGZsxQg3IhJu/2Nx3YIp2hx0LDVT9LZ1IjgrTIouCJDAZeD1dH1c5U rRfw== X-Received: by 10.70.118.165 with SMTP id kn5mr15655280pdb.140.1415756702187; Tue, 11 Nov 2014 17:45:02 -0800 (PST) Received: from localhost (ppp118-209-92-67.lns20.mel4.internode.on.net. [118.209.92.67]) by mx.google.com with ESMTPSA id rz6sm20432179pbc.74.2014.11.11.17.45.00 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 11 Nov 2014 17:45:01 -0800 (PST) References: From: Alexis Date: Wed, 12 Nov 2014 12:38:12 +1100 In-reply-to: Message-ID: <87oasd6vl4.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -4.0 (----) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -4.0 (----) Kevin W. Currey writes: > (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? For example, in Python: Python 2.7.3 (default, Mar 13 2014, 11:03:55) [GCC 4.7.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> 379.744 + 57.93 437.67400000000004 >>> Alexis. From debbugs-submit-bounces@debbugs.gnu.org Tue Nov 11 21:06:39 2014 Received: (at control) by debbugs.gnu.org; 12 Nov 2014 02:06:39 +0000 Received: from localhost ([127.0.0.1]:57997 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNKR-0005Cu-EH for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:06:39 -0500 Received: from ironport2-out.teksavvy.com ([206.248.154.181]:19082) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNKO-0005Cc-BN; Tue, 11 Nov 2014 21:06:36 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvAMAOatTlRLd+sd/2dsb2JhbABcgw6DYoZ+yDmDGgQCAoEcFwEBfIQDAQEEViMQCzQSFBgNJIhUy3IBAQEBAQEEAQEBAR6RCAeESwWLZKY8gW+EFh+CegEBAQ X-IPAS-Result: AvAMAOatTlRLd+sd/2dsb2JhbABcgw6DYoZ+yDmDGgQCAoEcFwEBfIQDAQEEViMQCzQSFBgNJIhUy3IBAQEBAQEEAQEBAR6RCAeESwWLZKY8gW+EFh+CegEBAQ X-IronPort-AV: E=Sophos;i="5.04,797,1406606400"; d="scan'208";a="96683190" Received: from 75-119-235-29.dsl.teksavvy.com (HELO pastel.home) ([75.119.235.29]) by ironport2-out.teksavvy.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 11 Nov 2014 21:06:35 -0500 Received: by pastel.home (Postfix, from userid 20848) id 96A78848C; Tue, 11 Nov 2014 21:06:35 -0500 (EST) From: Stefan Monnier To: "Kevin W. Currey" Subject: Re: bug#19025: 24.4; precision error when adding two floats Message-ID: References: Date: Tue, 11 Nov 2014 21:06:35 -0500 In-Reply-To: (Kevin W. Currey's message of "Tue, 11 Nov 2014 19:36:39 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: 0.3 (/) X-Debbugs-Envelope-To: control Cc: 19025-done@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.3 (/) tags 19025 notabug thanks > (message "%s" (+ 379.744 57.93)) > The above prints 437.67400000000004. That's the difference between floating-point numbers and real or rational numbers. > (message "%s" (format "%f" (+ 379.744 57.93))) You can cut the middle man: (message "%f" (+ 379.744 57.93)) But note that this prints something "incorrect": M-: (message "%f" (+ 379.744 57.93)) => 437.674000. M-: (equal (+ 379.744 57.93) 437.674000) => nil It's just that %f rounds differently. Stefan From unknown Sun Jun 22 03:56:45 2025 MIME-Version: 1.0 X-Mailer: MIME-tools 5.503 (Entity 5.503) X-Loop: help-debbugs@gnu.org From: help-debbugs@gnu.org (GNU bug Tracking System) To: "Kevin W. Currey" Subject: bug#19025: closed (Re: bug#19025: 24.4; precision error when adding two floats) Message-ID: References: X-Gnu-PR-Message: they-closed 19025 X-Gnu-PR-Package: emacs X-Gnu-PR-Keywords: notabug Reply-To: 19025@debbugs.gnu.org Date: Wed, 12 Nov 2014 02:07:03 +0000 Content-Type: multipart/mixed; boundary="----------=_1415758023-20092-1" This is a multi-part message in MIME format... ------------=_1415758023-20092-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Your bug report #19025: 24.4; precision error when adding two floats which was filed against the emacs package, has been closed. The explanation is attached below, along with your original report. If you require more details, please reply to 19025@debbugs.gnu.org. --=20 19025: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D19025 GNU Bug Tracking System Contact help-debbugs@gnu.org with problems ------------=_1415758023-20092-1 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 7bit Received: (at 19025-done) by debbugs.gnu.org; 12 Nov 2014 02:06:39 +0000 Received: from localhost ([127.0.0.1]:57995 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNKQ-0005Cp-Ut for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:06:39 -0500 Received: from ironport2-out.teksavvy.com ([206.248.154.181]:19082) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNKO-0005Cc-BN; Tue, 11 Nov 2014 21:06:36 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvAMAOatTlRLd+sd/2dsb2JhbABcgw6DYoZ+yDmDGgQCAoEcFwEBfIQDAQEEViMQCzQSFBgNJIhUy3IBAQEBAQEEAQEBAR6RCAeESwWLZKY8gW+EFh+CegEBAQ X-IPAS-Result: AvAMAOatTlRLd+sd/2dsb2JhbABcgw6DYoZ+yDmDGgQCAoEcFwEBfIQDAQEEViMQCzQSFBgNJIhUy3IBAQEBAQEEAQEBAR6RCAeESwWLZKY8gW+EFh+CegEBAQ X-IronPort-AV: E=Sophos;i="5.04,797,1406606400"; d="scan'208";a="96683190" Received: from 75-119-235-29.dsl.teksavvy.com (HELO pastel.home) ([75.119.235.29]) by ironport2-out.teksavvy.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 11 Nov 2014 21:06:35 -0500 Received: by pastel.home (Postfix, from userid 20848) id 96A78848C; Tue, 11 Nov 2014 21:06:35 -0500 (EST) From: Stefan Monnier To: "Kevin W. Currey" Subject: Re: bug#19025: 24.4; precision error when adding two floats Message-ID: References: Date: Tue, 11 Nov 2014 21:06:35 -0500 In-Reply-To: (Kevin W. Currey's message of "Tue, 11 Nov 2014 19:36:39 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: 0.3 (/) X-Debbugs-Envelope-To: 19025-done Cc: 19025-done@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.3 (/) tags 19025 notabug thanks > (message "%s" (+ 379.744 57.93)) > The above prints 437.67400000000004. That's the difference between floating-point numbers and real or rational numbers. > (message "%s" (format "%f" (+ 379.744 57.93))) You can cut the middle man: (message "%f" (+ 379.744 57.93)) But note that this prints something "incorrect": M-: (message "%f" (+ 379.744 57.93)) => 437.674000. M-: (equal (+ 379.744 57.93) 437.674000) => nil It's just that %f rounds differently. Stefan ------------=_1415758023-20092-1 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 7bit Received: (at submit) by debbugs.gnu.org; 12 Nov 2014 01:24:22 +0000 Received: from localhost ([127.0.0.1]:57961 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoMfV-0003oe-GU for submit@debbugs.gnu.org; Tue, 11 Nov 2014 20:24:22 -0500 Received: from eggs.gnu.org ([208.118.235.92]:40081) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoLvm-0002QM-Jy for submit@debbugs.gnu.org; Tue, 11 Nov 2014 19:37:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoLvc-0004dx-Ia for submit@debbugs.gnu.org; Tue, 11 Nov 2014 19:37:06 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: *** X-Spam-Status: No, score=3.6 required=5.0 tests=BAYES_50, FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,HTML_MESSAGE, RECEIVED_FROM_WINDOWS_HOST autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:43302) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoLvc-0004dr-F8 for submit@debbugs.gnu.org; Tue, 11 Nov 2014 19:36:56 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41724) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoLvU-0000kf-Qv for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 19:36:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoLvN-0004ac-7H for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 19:36:48 -0500 Received: from blu004-omc1s14.hotmail.com ([65.55.116.25]:58915) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoLvN-0004aN-22 for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 19:36:41 -0500 Received: from BLU173-W24 ([65.55.116.9]) by BLU004-OMC1S14.hotmail.com over TLS secured channel with Microsoft SMTPSVC(7.5.7601.22751); Tue, 11 Nov 2014 16:36:40 -0800 X-TMN: [C+JyY6c02cwC1Epj55I83Rd4doADuzO2] X-Originating-Email: [kevalier68@hotmail.com] Message-ID: Content-Type: multipart/alternative; boundary="_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_" From: "Kevin W. Currey" To: "bug-gnu-emacs@gnu.org" Subject: 24.4; precision error when adding two floats Date: Tue, 11 Nov 2014 19:36:39 -0500 Importance: Normal MIME-Version: 1.0 X-OriginalArrivalTime: 12 Nov 2014 00:36:40.0364 (UTC) FILETIME=[B996E6C0:01CFFE10] X-detected-operating-system: by eggs.gnu.org: Windows 7 or 8 [fuzzy] X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -3.8 (---) X-Debbugs-Envelope-To: submit X-Mailman-Approved-At: Tue, 11 Nov 2014 20:24:20 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.8 (---) --_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable (message "%s" (+ 379.744 57.93)) The above prints 437.67400000000004. Same if I use 57.930=2C but if I use = 57.931 (below) I get the correct answer 437.675. =20 (message "%s" (+ 379.744 57.931)) I was able to work around by using format: =20 (message "%s" (format "%f" (+ 379.744 57.93))) which prints 437.674000. =20 FYI=2C I can replicate the issue with Emacs 21.3.1. =20 Thanks=2C -Kevin =20 =20 In GNU Emacs 24.4.1 (x86_64-unknown-cygwin) of 2014-10-21 on desktop-new Windowing system distributor `Microsoft Corp.'=2C version 6.1.7601 Configured using: `configure --srcdir=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/src/emacs-24.4 --prefix=3D/usr --exec-prefix=3D/usr --bindir=3D/usr/bin --sbindir=3D/usr/= sbin --libexecdir=3D/usr/libexec --datadir=3D/usr/share --localstatedir=3D/var --sysconfdir=3D/etc --libdir=3D/usr/lib --datarootdir=3D/usr/share --docdir=3D/usr/share/doc/emacs --htmldir=3D/usr/share/doc/emacs/html -C --with-w32 --without-file-notification --enable-checking 'CFLAGS=3D-ggdb -O2 -pipe -Wimplicit-function-declaration -Og -g3 -fdebug-prefix-map=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/build= =3D/usr/src/debug/emacs-24.4-1 -fdebug-prefix-map=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/src/ema= cs-24.4=3D/usr/src/debug/emacs-24.4-1' CPPFLAGS=3D LDFLAGS=3D' =20 =20 Important settings: value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix =20 =20 Major mode: Fundamental =20 =20 Minor modes in effect: shell-dirtrack-mode: t display-time-mode: t mouse-wheel-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t line-number-mode: t Recent messages: Load-path shadows: None found. =20 =20 Features: (pp shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils info find-func grep tabify sh-script smie executable shell pcomplete compile comint ansi-color ring dabbrev cc-langs cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs arc-mode archive-mode dired-aux ispell apropos dired help-fns help-mode easymenu mule-util server edmacro kmacro cl-loaddefs cl-lib time jka-compr time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process dbusbind w32 multi-tty emacs) =20 =20 Memory information: ((conses 16 145217 10616) (symbols 48 23227 0) (miscs 40 133 446) (strings 32 31064 5702) (string-bytes 1 930985) (vectors 16 15771) (vector-slots 8 452262 7494) (floats 8 82 775) (intervals 56 640 31) (buffers 960 24)) = --_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
(message "%s" (+ 379.744 57.93))=

The above prints 437.67400000000004. =3B Same if I use 57.930= =2C but if I use =3B57.931 (below) I get the correct answer 437.675. =3B
(message "%s" (+ 379.744 57.931))

I was able to work ar= ound by using format:
 =3B
(message "%s" (format "%f" (+ 379.744 = 57.93)))

which prints 437.674000.
 =3B
FYI=2C I can replic= ate the issue with Emacs 21.3.1.
 =3B
Thanks=2C
-Kevin
&nbs= p=3B
 =3B
In GNU Emacs 24.4.1 (x86_64-unknown-cygwin)
 =3B= of 2014-10-21 on desktop-new
Windowing system distributor `Microsoft Cor= p.'=2C version 6.1.7601
Configured using:
 =3B`configure
 = =3B--srcdir=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/src/emacs-24.4<= br> =3B--prefix=3D/usr --exec-prefix=3D/usr --bindir=3D/usr/bin --sbind= ir=3D/usr/sbin
 =3B--libexecdir=3D/usr/libexec --datadir=3D/usr/shar= e --localstatedir=3D/var
 =3B--sysconfdir=3D/etc --libdir=3D/usr/lib= --datarootdir=3D/usr/share
 =3B--docdir=3D/usr/share/doc/emacs --ht= mldir=3D/usr/share/doc/emacs/html -C
 =3B--with-w32 --without-file-n= otification --enable-checking 'CFLAGS=3D-ggdb
 =3B-O2 -pipe -Wimplic= it-function-declaration -Og -g3
 =3B-fdebug-prefix-map=3D/home/kbrow= n/src/cygemacs/emacs-24.4-1.x86_64/build=3D/usr/src/debug/emacs-24.4-1
&= nbsp=3B-fdebug-prefix-map=3D/home/kbrown/src/cygemacs/emacs-24.4-1.x86_64/s= rc/emacs-24.4=3D/usr/src/debug/emacs-24.4-1'
 =3BCPPFLAGS=3D LDFLAGS= =3D'
 =3B
 =3B
Important settings:
 =3B value of $L= ANG: en_US.UTF-8
 =3B locale-coding-system: utf-8-unix
 =3B =3B
Major mode: Fundamental
 =3B
 =3B
Minor mode= s in effect:
 =3B shell-dirtrack-mode: t
 =3B display-time-mo= de: t
 =3B mouse-wheel-mode: t
 =3B file-name-shadow-mode: t<= br> =3B global-font-lock-mode: t
 =3B font-lock-mode: t
 = =3B blink-cursor-mode: t
 =3B line-number-mode: t

Recent mess= ages:
Load-path shadows:
None found.
 =3B
 =3B
Featu= res:
(pp shadow sort gnus-util mail-extr emacsbug message format-spec rf= c822
mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailab= brev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-utilmail-prsvr mail-utils info find-func grep tabify sh-script smie
executa= ble shell pcomplete compile comint ansi-color ring dabbrev
cc-langs cc-m= ode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-v= ars cc-defs arc-mode archive-mode dired-aux ispell apropos
dired help-fn= s help-mode easymenu mule-util server edmacro kmacro
cl-loaddefs cl-lib = time jka-compr time-date tooltip electric uniquify
ediff-hook vc-hooks l= isp-float-type mwheel w32-common-fns disp-table
w32-win w32-vars tool-ba= r dnd fontset image regexp-opt fringe
tabulated-list newcomment lisp-mod= e prog-mode register page menu-bar
rfn-eshadow timer select scroll-bar m= ouse jit-lock font-lock syntax
facemenu font-core frame cham georgian ut= f-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese = hebrew greek romanian slovak
czech european ethiopic indian cyrillic chi= nese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer nad= vice loaddefs button
faces cus-face macroexp files text-properties overl= ay sha1 md5 base64
format env code-pages mule custom widget hashtable-pr= int-readable
backquote make-network-process dbusbind w32 multi-tty emacs= )
 =3B
 =3B
Memory information:
((conses 16 145217 1061= 6)
 =3B(symbols 48 23227 0)
 =3B(miscs 40 133 446)
 = =3B(strings 32 31064 5702)
 =3B(string-bytes 1 930985)
 =3B(v= ectors 16 15771)
 =3B(vector-slots 8 452262 7494)
 =3B(floats= 8 82 775)
 =3B(intervals 56 640 31)
 =3B(buffers 960 24))
= --_d1d2cd7a-f2d6-4b97-a5fc-e39bdbee79ac_-- ------------=_1415758023-20092-1-- From unknown Sun Jun 22 03:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#19025: 24.4; precision error when adding two floats 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 To: 19025@debbugs.gnu.org Cc: jay.p.belanger@gmail.com Reply-To: jay.p.belanger@gmail.com Received: via spool by 19025-submit@debbugs.gnu.org id=B19025.141575932828514 (code B ref 19025); Wed, 12 Nov 2014 02:29:01 +0000 Received: (at 19025) by debbugs.gnu.org; 12 Nov 2014 02:28:48 +0000 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 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 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) 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) From: Jay Belanger References: <87oasd6vl4.fsf@gmail.com> Date: Tue, 11 Nov 2014 20:28:49 -0600 In-Reply-To: <87oasd6vl4.fsf@gmail.com> (Alexis's message of "Wed, 12 Nov 2014 12:38:12 +1100") Message-ID: <87mw7xtan2.fsf@gmail.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: -0.7 (/) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -0.7 (/) >> (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. From unknown Sun Jun 22 03:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#19025: 24.4; precision error when adding two floats Resent-From: Alexis Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 12 Nov 2014 02:50:02 +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 To: 19025@debbugs.gnu.org X-Debbugs-Original-To: bug-gnu-emacs@gnu.org Received: via spool by submit@debbugs.gnu.org id=B.141576056332043 (code B ref -1); Wed, 12 Nov 2014 02:50:02 +0000 Received: (at submit) by debbugs.gnu.org; 12 Nov 2014 02:49:23 +0000 Received: from localhost ([127.0.0.1]:58024 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNzn-0008Kk-Io for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:49:23 -0500 Received: from eggs.gnu.org ([208.118.235.92]:37848) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XoNzm-0008Kb-3r for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:49:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoNzf-00012l-Q3 for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:49:21 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=BAYES_40,FREEMAIL_FROM, T_DKIM_INVALID autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:45175) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoNzf-00012g-Nk for submit@debbugs.gnu.org; Tue, 11 Nov 2014 21:49:15 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39524) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoNzZ-0001W1-2Z for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:49:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoNzT-00011b-2v for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:49:09 -0500 Received: from mail-pa0-x231.google.com ([2607:f8b0:400e:c03::231]:47525) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoNzS-00011X-Rh for bug-gnu-emacs@gnu.org; Tue, 11 Nov 2014 21:49:03 -0500 Received: by mail-pa0-f49.google.com with SMTP id lj1so11874297pab.36 for ; Tue, 11 Nov 2014 18:49:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=references:from:to:subject:date:in-reply-to:message-id:mime-version :content-type; bh=gb0j4kp2zGpa2Pi8fN4WhDUrxdrd9vKa/c6azqM5DSs=; b=QOt0+3uJaytUbLFrIag0LkncEYOAAbBuRXNgRT2nyHdzdhzrmfmrvDh5gPxWQlqcA0 ITIPITBDU8Rm2/NN2EHO87s0O3pF4PJzZL5cyjZ0CJc7T15xy7KqFX2NnieCUF5dXlBR eSNoEDBDLa2qDkkbXJefZP2/3pirBHUpzoe0+u538jdlXDySXe7PScbi/hhjeA0d2sqz 8cKTbrmXHC2vdMOBMrwvFGGP3/w8bdaGMO9u878fldYHw+rCqAvAAuU3fJlLKAtSmpEg 0mMqwakK/2ErrmIPHHNdu7gKGoF7SqDPIATHo1lhnrluzDxADYPX60IU3Mm7vfrDfHaP BtvA== X-Received: by 10.70.129.135 with SMTP id nw7mr16752778pdb.129.1415760541856; Tue, 11 Nov 2014 18:49:01 -0800 (PST) Received: from localhost (ppp118-209-92-67.lns20.mel4.internode.on.net. [118.209.92.67]) by mx.google.com with ESMTPSA id nb3sm8180383pdb.18.2014.11.11.18.48.59 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 11 Nov 2014 18:49:00 -0800 (PST) References: <87oasd6vl4.fsf@gmail.com> <87mw7xtan2.fsf@gmail.com> From: Alexis Date: Wed, 12 Nov 2014 13:42:48 +1100 In-reply-to: <87mw7xtan2.fsf@gmail.com> Message-ID: <87mw7x6smg.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -4.0 (----) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -4.0 (----) Jay Belanger writes: >> 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. *nod* And perhaps mention Calc functions, which can work with a specified precision? (Assuming we can't simply link to e.g. http://floating-point-gui.de/ :-) ) Alexis.