From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23999 invoked by alias); 17 Mar 2008 23:20:11 -0000 Received: (qmail 23991 invoked by uid 22791); 17 Mar 2008 23:20:11 -0000 X-Spam-Check-By: sourceware.org Received: from mail.network-theory.co.uk (HELO mail.network-theory.co.uk) (66.199.228.187) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 17 Mar 2008 23:19:53 +0000 Date: Mon, 17 Mar 2008 23:20:00 -0000 Message-ID: <87r6e9x7jd.wl%bjg@network-theory.co.uk> From: Brian Gough To: GSL Discussion list Subject: Re: 64 bit rng interface? In-Reply-To: References: User-Agent: Wanderlust/2.14.0 (Africa) Emacs/22.1 Mule/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII X-Message-Mac: 29d15850a16d632163895b60597c6574 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: 2008-q1/txt/msg00041.txt.bz2 At Mon, 17 Mar 2008 10:27:57 -0400 (EDT), Robert G. Brown wrote: > a) Are there plans for a 64-bit GSL RNG interface? A number of my > correspondants are working on algorithms that can run equally well at 64 > bits, and 64 bit unsigned ints invert to double precision uniform > deviates. Is it possible to do it using the existing interface in some way? If it would need a duplicate 64-bit interface it's not really feasible. > b) Are there plans for a "vectorized" interface? I'd envision this > as a user-selectable switch on the creation/initialization step that > builds (say) a page-sized buffer. On the first call, this buffer would > be filled with random bits in a single step, keeping the generation code > on the CPU and cache and permitting certain pipelining optimizations. > Subsequent calls would simply walk a pointer through the buffer to the > end, where the "refill buffer" command would once again be called and > the pointer reset to the beginning before returning. The possibility is there to do that, or to provide a gsl_rng_get_array function. If there is a realistic benchmark that shows a large performance improvement (>2x) then that would be a good motivation. Currently it seems like motivation is the missing ingredient. -- Brian Gough