From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22722 invoked by alias); 12 Dec 2012 23:35:41 -0000 Received: (qmail 22581 invoked by uid 22791); 12 Dec 2012 23:35:40 -0000 X-SWARE-Spam-Status: No, hits=-3.5 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE X-Spam-Check-By: sourceware.org Received: from mail-ie0-f169.google.com (HELO mail-ie0-f169.google.com) (209.85.223.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 12 Dec 2012 23:35:35 +0000 Received: by mail-ie0-f169.google.com with SMTP id c14so3162163ieb.0 for ; Wed, 12 Dec 2012 15:35:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding :x-gm-message-state; bh=XebgPpbErUlm8ydilmnyqnpDfKrMao9WQ5jqH6i1SkU=; b=kdOfSxqxhc9KXEOl13ypdVjIVvufCfWr3HAX7MfB3EbSCs+MnfxGO3wvcACM6GeKxv sWEi03BvjEdeQAFoPQ/GqaO0Il0yAqQI0bcOAz/iRDbaMizFPh0BEr6vmWWVUjR0j2MS RVMZTN5F+lT1kjxQweCwClZ2kUAK+4HLomTVI4/Xx3VL3abcfB7ChrnN5XGrj/e/h2jy idkTG6tZjlWtX5cifq2Sc1EMRrDTiKUR7HEw3hUdX6EhCvMALxr616DcPIlzlgOed6WK Zc83pNHlVGsUJRnvy/cNfZztvyQ9smZlMxwl3/3ui+3YKPGAVf8pHqJfpwSRX1pdDx8/ 5psg== Received: by 10.50.15.134 with SMTP id x6mr15229670igc.27.1355355334605; Wed, 12 Dec 2012 15:35:34 -0800 (PST) Received: from MacBook-Pro-de-Maxime.local ([75.98.19.134]) by mx.google.com with ESMTPS id c3sm2963501igj.1.2012.12.12.15.35.33 (version=SSLv3 cipher=OTHER); Wed, 12 Dec 2012 15:35:34 -0800 (PST) Message-ID: <50C914C4.2060102@calculquebec.ca> Date: Wed, 12 Dec 2012 23:35:00 -0000 From: Maxime Boissonneault User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Rhys Ulerich CC: gsl-discuss@sourceware.org Subject: Re: Adding OpenMP support for some of the GSL functions References: <50C791BB.4060303@calculquebec.ca> <50C8F364.2010109@calculquebec.ca> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Gm-Message-State: ALoCoQlBEhnKRcxUiiM1d76qH8jL//+UyEezqaCXN6Xz0Gz58E1VyGJtqaOu2ox5L5JKWr28tD50 Mailing-List: contact gsl-discuss-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gsl-discuss-owner@sourceware.org X-SW-Source: 2012-q4/txt/msg00008.txt.bz2 Hi Rhys, I am not sure if you mean parallelizing the for loop in this code, but this would not work, as each iteration is not independent from the next one. Differential equation solving is intrinsically serial. I can not either just split the problem into smaller chunks (lets say 100k istead of 1M), because they are coupled, i.e. func can only be defined for the whole system, not for some of its parts. Thanks, Maxime Le 2012-12-12 16:36, Rhys Ulerich a écrit : >> I have not, since it is much simpler to add 6 pragmas to the loops of >> rk45_apply to achieve the same goal. > I suspect, from glancing at the first example at > http://www.gnu.org/software/gsl/manual/html_node/ODE-Example-programs.html, > you could achieve parallelization atop stock GSL builds with fewer > than 6 pragmas. > > I also suspect that by using OpenMP tasks over the coarser granularity > concept (1 ODE) instead of the parallel-fors over the finer > granularity method (1 step) you may see better overall performance. > > - Rhys