From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 9B75E138010 for ; Wed, 5 Sep 2012 15:26:59 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 26FF121C03C; Wed, 5 Sep 2012 15:26:30 +0000 (UTC) Received: from mail-ie0-f181.google.com (mail-ie0-f181.google.com [209.85.223.181]) by pigeon.gentoo.org (Postfix) with ESMTP id 4E82721C037 for ; Wed, 5 Sep 2012 15:24:44 +0000 (UTC) Received: by ieak12 with SMTP id k12so1249705iea.40 for ; Wed, 05 Sep 2012 08:24:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type :x-gm-message-state; bh=K3GhI3v5VqDPedREk6lvhvdjQbmnlQyGFi3f+nnWJq0=; b=Cv8WTiDNG3ui3Sttt2s8T+OG2+3Cdk61wwFFH8OboJdQpgAqpU/VrIIC5NxVDLkGyb 8bHrt6KPX6fWzeEsiY+T4aWoVD8C3k23UDzeIE3Nrts6WyuOCTzK4kwKJpjhv5BEoQnB ZzdM+Ohl1enB32NyYwnxeIOYIAHJ1HgKi02kbL4apkL0d1yaGgXfSSJ2cbBeEKAvnw19 00RB54EJsTJdDwNamtXbDnrSf0TWL6Q66roJVxyAUT/pn/dk1NqIRL7h9fgSNGW6ATsS MfldI7y9ql0bBaA8y1aehTeC/AvYaXKeJmTUZXwuWYyzvFO2JwXIR5bdLf6yTAujeoYg nwAg== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 Received: by 10.50.150.212 with SMTP id uk20mr642310igb.16.1346858683660; Wed, 05 Sep 2012 08:24:43 -0700 (PDT) Sender: antarus@scriptkitty.com Received: by 10.43.52.136 with HTTP; Wed, 5 Sep 2012 08:24:43 -0700 (PDT) In-Reply-To: References: <50411874.4060204@gentoo.org> <20120831214611.088b3f50@googlemail.com> <50469795.2070901@gentoo.org> <20120905122725.15d16d77@googlemail.com> Date: Wed, 5 Sep 2012 17:24:43 +0200 X-Google-Sender-Auth: srhAKtK125WxEspgwEazxHjf3Hc Message-ID: Subject: Re: [gentoo-dev] HDEPEND (host dependencies for cross-compilation) for EAPI 5? From: Alec Warner To: gentoo-dev@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 X-Gm-Message-State: ALoCoQl5T9PpMnJrFOCRqzljuqS5mryZ/IuRRxq1EBvvKaUH6SquwlAWS/qRCL26UTk26d44nrUO X-Archives-Salt: da9c5477-beca-414e-ac8e-0cffe62948b0 X-Archives-Hash: 95110ab2ec2aa4eb174a6af5fd166149 On Wed, Sep 5, 2012 at 2:46 PM, Rich Freeman wrote: > On Wed, Sep 5, 2012 at 7:27 AM, Ciaran McCreesh > wrote: >> Uhm. O(n) == O(n/2). Anything assuming they're different is just wrong. > > We're basically debating definitions. O notation is used to indicate > how algorithms scale and nobody uses O(n/2) and such as a result. > > An algorithm that is twice as slow is still twice as slow. That might > or might not matter. However, this isn't the domain where O notation > is used. You use O notation when your algorithm takes 30 seconds to > run and you want to know what happens with the dataset doubles 3000 > times. It generally doesn't matter if the result is that it will take > 1 trillion years to operate or 2 trillion years. You care more about > whether it will take minutes, hours, weeks, years, or whatever. > > I can't really think of any practical examples where multiplying the > time to parse a list of maybe 50 items vs 5 lists of 10 items is going > to make that big of a difference. They're just lines in a text file - > your CPU can compare a few billions characters per second. Sure, if > you add 75 layers of abstraction you might be able to find just the > right point where a factor of 5 is going to make it intolerable but a > factor of 1 is almost acceptable, but go ahead and add/remove a few > layers and suddenly it is all fine or all horrible anyway. That is a > bit contrived. That's why everybody ignores constant factors in O > notation anyway. so tl;dr, this doesn't matter because string comparison is very fast. -A > > Rich >