From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Pip Cet Newsgroups: gmane.emacs.bugs Subject: bug#38753: 27.0.60; cl--random-state uncontrolled growth due to bignums Date: Sun, 29 Dec 2019 17:33:59 +0000 Message-ID: References: <20191226171207.cepft7cjmmbuow6o@nullprogram.com> <20191229142718.q2vvumr6e7pbobdu@nullprogram.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="156619"; mail-complaints-to="usenet@blaine.gmane.org" Cc: 38753@debbugs.gnu.org To: Christopher Wellons Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Dec 29 18:35:16 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ilcT9-000eQs-S6 for geb-bug-gnu-emacs@m.gmane.org; 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Sun, 29 Dec 2019 09:34:35 -0800 (PST) In-Reply-To: <20191229142718.q2vvumr6e7pbobdu@nullprogram.com> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:173900 Archived-At: On Sun, Dec 29, 2019 at 2:27 PM Christopher Wellons wrote: > > Any idea how easy it would be to fix either of them, or both? > The reason I found that bug is because I was experimenting with > addressing exactly that problem: > > https://github.com/skeeto/lcg128 > > It's got the right features, including support for arbitrary limits (per > your example), but I'm not satisfied with the performance. That looks excellent. Maybe we should be using a cryptographic RNG by default, though? I really don't know the tradeoffs, though. At first glance, there are two questions I have about lcg128: - should random floats have more than 53 significant bits if they're < 0.5? I think the answer is yes, even though that will make the implementation harder. - should (lcg128-range 2^n) call the generator twice, on average? I think it's an important special case in which we only want to call the generator once.