From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Max Nikulin Newsgroups: gmane.emacs.devel Subject: Re: hypotenuse Date: Sun, 21 Jul 2024 22:54:53 +0700 Message-ID: References: <8734o9sdig.fsf@posteo.net> <87wmllqq66.fsf@posteo.net> <87plrdqnhc.fsf@posteo.net> <87le21qldj.fsf_-_@posteo.net> <878qy1at52.fsf@dataswamp.org> <87plr6u8al.fsf_-_@dataswamp.org> <86wmleby8w.fsf@gnu.org> <86sew2bxii.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="8852"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mozilla Thunderbird To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Jul 21 18:02:56 2024 Return-path: Envelope-to: ged-emacs-devel@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 1sVZ1U-00028S-69 for ged-emacs-devel@m.gmane-mx.org; Sun, 21 Jul 2024 18:02:56 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sVZ12-0005yy-7p; Sun, 21 Jul 2024 12:02:28 -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 1sVYts-00025y-1H for emacs-devel@gnu.org; Sun, 21 Jul 2024 11:55:04 -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 1sVYtq-0004p0-Ct for emacs-devel@gnu.org; Sun, 21 Jul 2024 11:55:03 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1sVYtn-0004JX-Ty for emacs-devel@gnu.org; Sun, 21 Jul 2024 17:54:59 +0200 X-Injected-Via-Gmane: http://gmane.org/ Content-Language: en-US, ru-RU In-Reply-To: Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: 23 X-Spam_score: 2.3 X-Spam_bar: ++ X-Spam_report: (2.3 / 5.0 requ) BAYES_00=-1.9, DKIM_ADSP_CUSTOM_MED=0.001, FORGED_GMAIL_RCVD=1, FORGED_MUA_MOZILLA=2.309, FREEMAIL_FORGED_FROMDOMAIN=0.001, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.001, NML_ADSP_CUSTOM_MED=0.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Sun, 21 Jul 2024 12:02:27 -0400 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:321901 Archived-At: On 21/07/2024 22:12, Christopher Dimech wrote: >>>> (defun hypotenuse (c1 c2) >>>> (sqrt (+ (* c1 c1) (* c2 c2))) ) > > I have a solution to the problem in fortran, but not in elisp. I could > include it. Its implementation required serious concentration. Underflow/overflow issues may be solved with a few lines of code and it does matter if it is fortran, elisp, or another language (besides pathological ones). The problem is to avoid error above 1 ULP. In 2021 hypot implementation in glibc was replaced by a more precise one: https://sourceware.org/git/?p=glibc.git;a=commit;h=6c848d70383e1dbe932ef41723ac0abfdeec7ca8