Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.fsmpi.rwth-aachen.de!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed3a.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.004 X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'interpreter': 0.05; 'anders': 0.09; 'from:addr:ethan': 0.09; 'from:addr:stoneleaf.us': 0.09; 'from:name:ethan furman': 0.09; 'message-id:@stoneleaf.us': 0.09; 'raises': 0.09; '~ethan~': 0.09; 'python': 0.11; 'creates': 0.14; '12:04': 0.16; 'exception?': 0.16; 'nan': 0.16; 'raised.': 0.16; 'exception': 0.16; 'wrote:': 0.18; '>>>': 0.22; 'example': 0.22; 'header:User-Agent:1': 0.23; 'header:In-Reply-To:1': 0.27; 'appear': 0.29; 'is?': 0.30; 'apparently': 0.31; 'created': 0.35; 'otherwise.': 0.36; 'charset:us-ascii': 0.36; 'wrong': 0.37; 'to:addr:python-list': 0.38; 'pm,': 0.38; 'to:addr:python.org': 0.39; 'received:173': 0.61; 'received:69.56': 0.68; 'subject:For': 0.78; 'computation,': 0.84; 'ethan': 0.84; 'furman': 0.84; 'received:69.56.148': 0.84 Date: Tue, 08 Jul 2014 12:16:47 -0700 From: Ethan Furman User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: python-list@python.org Subject: Re: NaN comparisons - Call For Anecdotes References: <53BC05FB.4050707@jmunch.dk> <53BC2BA0.3050500@stoneleaf.us> <53BC40AF.50407@jmunch.dk> In-Reply-To: <53BC40AF.50407@jmunch.dk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator3304.hostgator.com X-AntiAbuse: Original Domain - python.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - stoneleaf.us X-BWhitelist: no X-Source-IP: 173.12.184.233 X-Exim-ID: 1X4ash-0007Z1-Ku X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([173.12.184.233]) [173.12.184.233]:58878 X-Source-Auth: ethan+stoneleaf.us X-Email-Count: 2 X-Source-Cap: dG9idWs7dG9idWs7Z2F0b3IzMzA0Lmhvc3RnYXRvci5jb20= X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 18 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1404848493 news.xs4all.nl 2829 [2001:888:2000:d::a6]:44962 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:74207 On 07/08/2014 12:04 PM, Anders J. Munch wrote: > Ethan Furman skrev: > >> What exception? Apparently your claims about NaN in Python are all wrong -- have you been using a custom interpreter? >> >>> float('inf') - float('inf') >> nan > > If you deliberately try to manufacture NaN's, you can. I never said otherwise. What you said is: "They just don't appear in normal computation, because the interpreter raises an exception instead." I just ran a calculation that created a NaN, the same as 4 - 3 creates a 1, and no exception was raised. Do you have an example where one is? -- ~Ethan~