From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by yquem.inria.fr (Postfix) with ESMTP id 966CCBB84 for ; Thu, 18 May 2006 22:14:36 +0200 (CEST) Received: from cgpsrv2.cis.mcmaster.ca (univmail.CIS.McMaster.CA [130.113.64.46]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id k4IKEZxl014947 for ; Thu, 18 May 2006 22:14:36 +0200 Received: from [130.113.68.27] (account carette@univmail.cis.mcmaster.ca [130.113.68.27] verified) by cgpsrv2.cis.mcmaster.ca (CommuniGate Pro SMTP 4.1.8) with ESMTP id 126595608; Thu, 18 May 2006 16:14:35 -0400 Message-ID: <446CD5D7.30903@mcmaster.ca> Date: Thu, 18 May 2006 16:15:19 -0400 From: Jacques Carette Organization: McMaster University User-Agent: Mozilla Thunderbird 1.0.6 (Windows/20050716) X-Accept-Language: en-us, en MIME-Version: 1.0 To: David Brown Cc: caml-list@yquem.inria.fr Subject: Re: [Caml-list] compiler bug? References: <20060517231426.30289.qmail@web32203.mail.mud.yahoo.com> <446CABCA.8000906@inria.fr> <446CB021.6000009@mcmaster.ca> <446CB2EE.1080102@inria.fr> <446CCB8E.8080601@mcmaster.ca> <20060518200732.GA31619@old.davidb.org> In-Reply-To: <20060518200732.GA31619@old.davidb.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Miltered: at nez-perce with ID 446CD5AB.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; compiler:01 bug:01 algebra:01 worst-case:01 worst-case:01 compiler:01 ocaml:01 functors:01 wrote:01 caml-list:01 compile:01 jacques:01 jacques:01 mcmaster:02 generally:03 X-Spam-Checker-Version: SpamAssassin 3.0.3 (2005-04-27) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.0.3 David Brown wrote: >>In Computer Algebra, people use Groebner bases all the time. They have >>doubly-exponential worst-case complexity -- but seem to work rather well >>in practice. So I have stopped paying attention to worst-case; average >>case, when available, does matter a lot more. >> >> > >Except when someone made a decision like this, in say a revision control >system, and suddenly you discover that you've provoked a worst case >scenario, and it suddenly takes hundreds of cpu hours to check in a file >rather than a few seconds. > > I see you've used ClearCase! Rather unpleasant experience. >For something like a compiler, worse case behavior is very important. It >is not generally acceptable for a build to just hang in the compiler. > Not the compiler, the super-optimizing pass in the compiler. I completely agree that the base compiler should not hang a build, and that complexity (including worst-case) there matters a lot. Speaking of which, have you ever tried to compile an Ocaml program with a LOT of functors in it? It requires quite a bit of patience... Jacques