From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Rast Subject: Re: [PATCH 2/2] Document the --histogram diff option Date: Tue, 6 Mar 2012 21:42:50 +0100 Message-ID: <87fwdl1mwl.fsf@thomas.inf.ethz.ch> References: <7vd38psdt4.fsf@alter.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Thomas Rast , , Michal Privoznik , Jeff King To: Junio C Hamano X-From: git-owner@vger.kernel.org Tue Mar 06 21:43:04 2012 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1S51Do-0006Tc-SM for gcvg-git-2@plane.gmane.org; Tue, 06 Mar 2012 21:43:01 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031060Ab2CFUm4 (ORCPT ); Tue, 6 Mar 2012 15:42:56 -0500 Received: from edge20.ethz.ch ([82.130.99.26]:2668 "EHLO edge20.ethz.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031036Ab2CFUmz (ORCPT ); Tue, 6 Mar 2012 15:42:55 -0500 Received: from CAS21.d.ethz.ch (172.31.51.111) by edge20.ethz.ch (82.130.99.26) with Microsoft SMTP Server (TLS) id 14.1.355.2; Tue, 6 Mar 2012 21:42:53 +0100 Received: from thomas.inf.ethz.ch.ethz.ch (213.55.184.242) by CAS21.d.ethz.ch (172.31.51.111) with Microsoft SMTP Server (TLS) id 14.1.355.2; Tue, 6 Mar 2012 21:42:53 +0100 In-Reply-To: <7vd38psdt4.fsf@alter.siamese.dyndns.org> (Junio C. Hamano's message of "Tue, 06 Mar 2012 11:57:11 -0800") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) X-Originating-IP: [213.55.184.242] Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Junio C Hamano writes: > Thomas Rast writes: > >> Signed-off-by: Thomas Rast >> --- >> >> This is only the minimal update. I think in the long run, we should >> add a note saying why we support all of them. But off hand I didn't >> have any substantial evidence in favour of patience that could be used >> as an argument. > > Isn't the main argument made by proponents of patience diff is more > readable output, and not performance? That line of argument relies > on a fairly subjective test "which one is easier to read?", so it is > hard to come up with a substantial evidence, unless somebody invests > in A/B test. Well, I was just too lazy to look up what I dimly remembered people had posted at some point: examples where patience beats Myers for readability. E.g., http://article.gmane.org/gmane.comp.version-control.git/104316 I don't think you need a blind test to justify that the patience result is more readable. So I think in the long run, the docs should say something like: --diff-algorithm={histogram|myers|minimal|patience}:: Choose a diff algorithm. The variants are as follows: + -- histogram:: This is the fastest algorithm, and thus the default. myers:: The classical Myers diff algorithm. minimal:: Like 'myers', but spend extra time making sure that the diff is the shortest possible for the set of changes performed. patience:: The patience diff algorithm, which first matches unique lines with each other. This sometimes results in more readable (if longer) patches than the other algorithms. -- Or whatever -- magic is required to have a nested list in asciidoc. I can't be bothered to twiddle with that right now. -- Thomas Rast trast@{inf,student}.ethz.ch