From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 2667d5c: Add new functions for the root mean square of a (Calc) vector Date: Wed, 16 Sep 2015 15:46:58 +0200 Message-ID: <87fv2esch9.fsf@fencepost.gnu.org> References: <20150916005352.1277.32898@vcs.savannah.gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1442411272 3552 80.91.229.3 (16 Sep 2015 13:47:52 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 16 Sep 2015 13:47:52 +0000 (UTC) Cc: Jay Belanger , emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Sep 16 15:47:46 2015 Return-path: Envelope-to: ged-emacs-devel@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 1ZcD3p-0006Wo-La for ged-emacs-devel@m.gmane.org; Wed, 16 Sep 2015 15:47:45 +0200 Original-Received: from localhost ([::1]:50891 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZcD3p-0002VP-9O for ged-emacs-devel@m.gmane.org; Wed, 16 Sep 2015 09:47:45 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60249) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZcD39-0001mK-R7 for emacs-devel@gnu.org; Wed, 16 Sep 2015 09:47:07 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZcD39-00005T-2e for emacs-devel@gnu.org; Wed, 16 Sep 2015 09:47:03 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:41369) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZcD36-0008WT-Ae; Wed, 16 Sep 2015 09:47:00 -0400 Original-Received: from localhost ([127.0.0.1]:55188 helo=lola) by fencepost.gnu.org with esmtp (Exim 4.82) (envelope-from ) id 1ZcD35-0006dM-P6; Wed, 16 Sep 2015 09:47:00 -0400 Original-Received: by lola (Postfix, from userid 1000) id 02F89DF4A4; Wed, 16 Sep 2015 15:46:58 +0200 (CEST) In-Reply-To: (Stefan Monnier's message of "Wed, 16 Sep 2015 09:21:40 -0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:190010 Archived-At: Stefan Monnier writes: > -*- mode: nit-pick -*- > >> +Another commonly used mean, the RMS (root-mean-square), can be computed >> +for a vector of numbers by using the @kbd{u R} > > I must admit that I don't use Calc very often, and read its manual even > less often, so clearly I'm taking this out of context, but in any case: > > To me a "vector" has a rather specific meaning, and taking the root mean > square of a vector doesn't make much sense. Instead, I like to take the > rms of a *set* of numbers (which may be provided by packaging them in > a vector, of course). Why would you ever want to do that? It may at best make sense for a finite _multiset_ (which can conveniently be represented by vector elements). The only difference then is that the members of a multiset have no order. But once you move to infinite measures as the base, RMS is still well-defined but you'd rarely want to remove the order by only viewing cumulative density functions. At any rate, you could do s/vector of numbers/the numbers in a vector/ but indeed that may suggest that it may not count 1 twice in [1;2;1] because the "numbers" are just 1 and 2. So one would probably rather do s/vector of numbers/the vector elements/. -- David Kastrup