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 1E149D55E for ; Sun, 31 Jul 2005 01:33:06 +0200 (CEST) Received: from mail.physik.uni-muenchen.de (mail.physik.uni-muenchen.de [192.54.42.129]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j6UNX5YR011284 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Sun, 31 Jul 2005 01:33:05 +0200 Received: from localhost (unknown [127.0.0.1]) by mail.physik.uni-muenchen.de (Postfix) with ESMTP id 703202001B; Sun, 31 Jul 2005 01:33:05 +0200 (CEST) Received: from mail.physik.uni-muenchen.de ([127.0.0.1]) by localhost (mail.physik.uni-muenchen.de [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 30710-02-6; Sun, 31 Jul 2005 01:33:03 +0200 (CEST) Received: from mailhost.cip.physik.uni-muenchen.de (kaiser.cip.physik.uni-muenchen.de [141.84.136.1]) by mail.physik.uni-muenchen.de (Postfix) with ESMTP id A90AC20015; Sun, 31 Jul 2005 01:33:03 +0200 (CEST) Received: from gamshag.cip.physik.uni-muenchen.de (gamshag.cip.physik.uni-muenchen.de [141.84.136.22]) by mailhost.cip.physik.uni-muenchen.de (Postfix) with ESMTP id 5F3CC26EDA; Sun, 31 Jul 2005 01:33:03 +0200 (CEST) Received: by gamshag.cip.physik.uni-muenchen.de (Postfix, from userid 3092) id 3DF6016B59; Sun, 31 Jul 2005 01:33:03 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by gamshag.cip.physik.uni-muenchen.de (Postfix) with ESMTP id 3A62F22144; Sun, 31 Jul 2005 01:33:03 +0200 (CEST) Date: Sun, 31 Jul 2005 01:33:03 +0200 (CEST) From: Thomas Fischbacher To: David Thomas Cc: caml-list@yquem.inria.fr Subject: Re: [Caml-list] How to do this properly with OCaml? In-Reply-To: <20050727153558.80900.qmail@web30515.mail.mud.yahoo.com> Message-ID: References: <20050727153558.80900.qmail@web30515.mail.mud.yahoo.com> X-BOFH: Daemons did it MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Virus-Scanned: amavisd-new at physik.uni-muenchen.de X-Miltered: at nez-perce with ID 42EC0E31.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; caml-list:01 ocaml:01 arrays:01 geometric:01 subset:01 geometric:01 binary:01 heap:01 2005,:98 ...:98 ...:98 cip:98 cip:98 lambda:01 lambda:01 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=SPF_FAIL autolearn=disabled version=3.0.3 On Wed, 27 Jul 2005, David Thomas wrote: > I'm still curious what numerical algorithm is so > desperately in need of variable length arrays... There are quite some geometric algorithms where you want to process a subset (of a priori unknown size) of all geometric entities that satisfy a certain constraint by decreasing priority. Using a binary heap implemented on top of an array often is a reasonable choice there. I am not an expert on this, but I think that even some algorithms that deal with the problem of permuting indices of a sparse matrix to optimize cache efficiency of subsequent matrix-vector products may belong to this category. Now if the sparse matrix is not known a priori, but assembled at run time... -- regards, tf@cip.physik.uni-muenchen.de (o_ Thomas Fischbacher - http://www.cip.physik.uni-muenchen.de/~tf //\ (lambda (n) ((lambda (p q r) (p p q r)) (lambda (g x y) V_/_ (if (= x 0) y (g g (- x 1) (* x y)))) n 1)) (Debian GNU)