From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Newsgroups: gmane.emacs.bugs Subject: bug#41279: 26.3; Calc: sum(gcd(0,n),n,-1,-1) evaluates to -1 Date: Fri, 15 May 2020 12:19:14 +0200 Message-ID: <7D48D15C-1F8E-41C8-9B1C-650215C8101D@acm.org> References: Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.14\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="27692"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 41279@debbugs.gnu.org To: David Ongaro Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri May 15 12:23:42 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jZXVG-00078B-3T for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 15 May 2020 12:23:42 +0200 Original-Received: from localhost ([::1]:57936 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZXVF-00068S-6O for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 15 May 2020 06:23:41 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:46842) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZXRi-00013K-8h for bug-gnu-emacs@gnu.org; Fri, 15 May 2020 06:20:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:52600) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jZXRh-0003p6-W3 for bug-gnu-emacs@gnu.org; Fri, 15 May 2020 06:20:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jZXRh-0005ez-SS for bug-gnu-emacs@gnu.org; Fri, 15 May 2020 06:20:01 -0400 X-Loop: help-debbugs@gnu.org In-Reply-To: Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 15 May 2020 10:20:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41279 X-GNU-PR-Package: emacs Original-Received: via spool by 41279-submit@debbugs.gnu.org id=B41279.158953797821723 (code B ref 41279); Fri, 15 May 2020 10:20:01 +0000 Original-Received: (at 41279) by debbugs.gnu.org; 15 May 2020 10:19:38 +0000 Original-Received: from localhost ([127.0.0.1]:35913 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jZXR9-0005e7-4k for submit@debbugs.gnu.org; Fri, 15 May 2020 06:19:38 -0400 Original-Received: from mail1464c50.megamailservers.eu ([91.136.14.64]:43388 helo=mail268c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jZXR6-0005ds-Hj for 41279@debbugs.gnu.org; Fri, 15 May 2020 06:19:25 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1589537957; bh=6f7rHVEPLWKcNrB3Q8oOPMgShf6jcWcI/8XrpFwmS1I=; h=From:Subject:Date:Cc:To:From; b=JKfNQl22vrnV74y5oCUa4IHRzYe8C3c2eJxYWjp+/AuECXBcPj2nUdlkDH1jn8Cu6 rdr+eDwAyjQnZIGndwnMVjCtADGWA0qxRb9S/bWosPq9H0/m1fJ0sWF21Vb+TYQ/ke ONtGrr8viHkwIUVjp2KV0gRhcVjTbgEXgPuPhtvU= Feedback-ID: mattiase@acm.or Original-Received: from stanniol.lan (c-4e4ae655.032-75-73746f71.bbcust.telenor.se [85.230.74.78]) (authenticated bits=0) by mail268c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 04FAJFr2027086; Fri, 15 May 2020 10:19:16 +0000 X-Mailer: Apple Mail (2.3445.104.14) X-CTCH-RefID: str=0001.0A782F18.5EBE6C3F.00A2, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: 0.000 X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-CSC: 0 X-CHA: v=2.3 cv=BZ+mLYl2 c=1 sm=1 tr=0 a=klNLuyVZdLUgl+K5Uafb2A==:117 a=klNLuyVZdLUgl+K5Uafb2A==:17 a=kj9zAlcOel0A:10 a=M51BFTxLslgA:10 a=ghBovyFD5biq_iQvZ9IA:9 a=MEnuKdxVvYCi6RlQ:21 a=TG2vjweC-eppCdnI:21 a=CjuIK1q_8ugA:10 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:180306 Archived-At: Thank you for reporting this. It seems that Calc first simplifies = gcd(0,n) to n and then computes sum(n,n,-1,-1) =3D -1. We could either make gcd(0,x)=3Dgcd(x,0)=3D|x|, or try preventing sum = from simplifying its operand first, or both. For the smallest possible change, what about the hack below? --- a/lisp/calc/calc-comb.el +++ b/lisp/calc/calc-comb.el @@ -241,8 +241,8 @@ calcFunc-gcd (calcFunc-gcd (math-neg a) b)) ((Math-looks-negp b) (calcFunc-gcd a (math-neg b))) - ((Math-zerop a) b) - ((Math-zerop b) a) + ((Math-zerop a) (math-abs b)) + ((Math-zerop b) (math-abs a)) ((and (Math-ratp a) (Math-ratp b)) (math-make-frac (math-gcd (if (eq (car-safe a) 'frac) (nth 1 a) = a)