Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!us.feeder.erje.net!news2.arglkargh.de!zen.net.uk!dedekind.zen.co.uk!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed1.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 0.009 X-Spam-Evidence: '*H*': 0.98; '*S*': 0.00; 'cpython': 0.05; 'correct.': 0.07; 'lookup': 0.09; 'algorithmic': 0.16; 'dict': 0.16; 'dictionary,': 0.16; 'from:addr:torriem': 0.16; 'from:name:michael torrie': 0.16; 'lookups': 0.16; "object's": 0.16; 'ought': 0.16; 'subject:slow': 0.16; 'wrote:': 0.18; 'wed,': 0.18; 'bit': 0.19; 'header:User-Agent:1': 0.23; 'header:In-Reply- To:1': 0.27; 'function': 0.29; 'michael': 0.29; 'chris': 0.29; 'am,': 0.29; 'related': 0.29; 'equivalent.': 0.31; 'overhead': 0.31; 'sep': 0.31; 'probably': 0.32; 'figure': 0.32; "we're": 0.32; 'call.': 0.33; 'guess': 0.33; 'implemented': 0.33; 'but': 0.35; 'list': 0.37; 'message-id:@gmail.com': 0.38; 'to:addr :python-list': 0.38; 'issue': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'is.': 0.60; "you're": 0.61; 'yes': 0.68; 'complexity': 0.84; 'faster.': 0.84 X-Virus-Scanned: amavisd-new at torriefamily.org Date: Tue, 09 Sep 2014 09:57:02 -0600 From: Michael Torrie User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20131118 Thunderbird/17.0.11 MIME-Version: 1.0 To: python-list@python.org Subject: Re: weakref, memory management and execution slow down in PyQt4 References: <540BFE43.5030006@riseup.net> <540CADDD.3050501@riseup.net> <540CB15C.2060008@gmail.com> <540CC278.4050106@riseup.net> <540E40FD.8030706@gmail.com> <540E69AF.5040309@riseup.net> <540F1D83.1010602@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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: 16 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1410278232 news.xs4all.nl 2829 [2001:888:2000:d::a6]:52779 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:77744 On 09/09/2014 09:37 AM, Chris Angelico wrote: > On Wed, Sep 10, 2014 at 1:32 AM, Michael Torrie wrote: >> Yes you're correct. It is the equivalent. But it always involves >> lookup in the object's dictionary, which is big O order O(n log n) >> complexity for each and every access. > > Where do you get that figure from? A CPython dictionary is implemented > as a hashtable, so algorithmic complexity of lookups ought to be O(1). You're right, it is. My mistake. Guess the main issue is the overhead of an additional function call. A dict directly or a list directly may me faster. Anyway, I guess we're wandering in the weeds a bit as the original issue is probably not related to his unorthodox choice of metaprogramming as a data model.