From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: percent-change Date: Mon, 15 May 2023 04:54:11 +0200 Message-ID: <87fs7y719o.fsf@dataswamp.org> References: <87r0rnxa6v.fsf@dataswamp.org> <87zg68w73s.fsf@dataswamp.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="23039"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:bqWG3FZ8MItok/pu6svjPugVORY= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon May 15 19:05:26 2023 Return-path: Envelope-to: geh-help-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 1pybdT-0005eN-Nj for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 15 May 2023 19:05:23 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pybcw-0007vo-VA; Mon, 15 May 2023 13:04:51 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pyOLu-0007q1-Vz for help-gnu-emacs@gnu.org; Sun, 14 May 2023 22:54:26 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pyOLt-0006Ep-CD for help-gnu-emacs@gnu.org; Sun, 14 May 2023 22:54:22 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1pyOLr-0003Zc-0Z for help-gnu-emacs@gnu.org; Mon, 15 May 2023 04:54:19 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Mon, 15 May 2023 13:04:47 -0400 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:143617 Archived-At: Yuri Khan wrote: >> But how/why does that work if 'from' is 0? >> >> (/ 1 0 0.01) ; 1.0e+INF >> >> What does that mean? > > In floating point, dividing by zero is allowed and yields > +infinity, -infinity or (quiet) not-a-number depending on > the sign of the numerator. ‘/’ knows to perform the division > in floating when at least one operand is a float, which 0.01 > nicely provides. 1.0e+INF is just the printed representation > for positive infinity. A quiet NaN is not signalled. [1] (/ 1 0.0) ; 1.0e+INF (/ 0 0.0) ; -0.0e+NaN (/ -1 0.0) ; -1.0e+INF Yes, it is as you say, but why? Maybe the answer is TLDR: https://en.wikipedia.org/wiki/Division_by_zero [1] https://stackoverflow.com/questions/18118408/what-is-the-difference-between-quiet-nan-and-signaling-nan -- underground experts united https://dataswamp.org/~incal