From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ealdwulf Wuffinga Subject: Re: Generalised bisection Date: Fri, 13 Mar 2009 10:00:53 +0000 Message-ID: References: <200903100808.15875.chriscool@tuxfamily.org> <43d8ce650903110235q5e2a59f6t201d5e65a4937476@mail.gmail.com> <43d8ce650903112345x3d40b70ap7e4c0f8c7d0b6069@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Johannes Schindelin , John Tapsell , Christian Couder , Git List To: Steven Tweed X-From: git-owner@vger.kernel.org Fri Mar 13 11:10:47 2009 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1Li4Ld-00036S-1P for gcvg-git-2@gmane.org; Fri, 13 Mar 2009 11:10:37 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754063AbZCMKIl (ORCPT ); Fri, 13 Mar 2009 06:08:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752331AbZCMKIl (ORCPT ); Fri, 13 Mar 2009 06:08:41 -0400 Received: from mail-bw0-f175.google.com ([209.85.218.175]:51245 "EHLO mail-bw0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751306AbZCMKIk (ORCPT ); Fri, 13 Mar 2009 06:08:40 -0400 X-Greylist: delayed 464 seconds by postgrey-1.27 at vger.kernel.org; Fri, 13 Mar 2009 06:08:39 EDT Received: by bwz23 with SMTP id 23so53583bwz.37 for ; Fri, 13 Mar 2009 03:08:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=7yr4u2CnGkVCmk14dMqmFyLczCZ1PBSyjhaEO8I2xXI=; b=aCvh9A5MIkjdD3uBoegcRbylRvzlwP1VdUGruFVK/fGC6SqdxVOi/R7y5Lzcd0HZW0 S+dvBKGQyQnJrrbrwgUFac12CFWGLhU9hVpQtmPg6/wD4PCGM6xAZ/Yi/k0LDxSRpMac i5iIyF2qOOFt/swgU+TGU7WcJFDNeSQgS06xU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=S4l8GsWeTLmXAgpwJpc85t241B9ihGzxEQtZhoJLPlxxof0FhFRoS+OMrbw70Twbzk eJ7Y8HaXoBps1AOx/i9waV2ogX0XgR0XiqTdmGl0pun29uZC4O15NA34JZ5oqgjn+Bvc lklzlm5gtaX6li738UHveXtFfXJDvmNF2KsSQ= Received: by 10.204.57.79 with SMTP id b15mr336513bkh.172.1236938453488; Fri, 13 Mar 2009 03:00:53 -0700 (PDT) In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Thu, Mar 12, 2009 at 6:02 PM, Steven Tweed wrote: > I haven't even looked at the source code so a description of the > mathematical algorithm would help, but I'll just point out that > underflow (in the case of working with probabilities) and overflow > (when working with their negated logarithms) is inherent in most > multi-step Bayesian algorithms. The only solution is to rescale things > as you go so that things stay in a "computable" range. (You're almost > never interested in absolute probabilities anyway but rather relative > probabilities or, in extreme cases, just the biggest probability, so > rescaling isn't losing any useful information.) Hmm, I'll have to think about that one. Ealdwulf