From ... Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!skynet.be!skynet.be!ossa.telenet-ops.be!nmaster.kpnqwest.net!nreader2.kpnqwest.net.POSTED!not-for-mail Newsgroups: comp.lang.lisp Subject: Re: CMUCL18d on Alpha? References: <3CBA8472.48774F5C@ilt.fhg.de> <3CBBE1E6.93F85F44@ilt.fhg.de> <3CBBF4AC.39CD4A4C@kfunigraz.ac.at> <3CBE88D1.6A17BCE1@ilt.fhg.de> <3CBFBF03.31766207@ilt.fhg.de> <87g01r384r.fsf@nkapi.internal> Mail-Copies-To: never From: Erik Naggum Message-ID: <3228232604375936@naggum.net> Organization: Naggum Software, Oslo, Norway Lines: 25 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 19 Apr 2002 19:16:44 GMT X-Complaints-To: newsmaster@KPNQwest.no X-Trace: nreader2.kpnqwest.net 1019243804 193.71.199.50 (Fri, 19 Apr 2002 21:16:44 MET DST) NNTP-Posting-Date: Fri, 19 Apr 2002 21:16:44 MET DST Xref: archiver1.google.com comp.lang.lisp:32038 * Bulent Murtezaoglu | Yes, but if you assume that the numbers read have been printed by some | other program that uses the same internal float representation, then this | complication disappears, does it not? No. The problem lies in the rounding errors that can easily be introduced by the division and multiplication by (powers of) 10. You have to be _very_ careful with these operations to avoid introducing errors. If done incorrectly, they may even be relatively large and lead to propagating problems. | That is, given A.BdEE, printed from an IEEE double in decimal radix with | B l digits log, it seems we should be able to assume that (* (+ Ad0 Bd-l) | 1dEE) will retrieve the original IEEE double. At least I don't see how | this would fail. Then try it out. This is easy as long as you have an ample supply of precision bits, but that is not true for the least significant bits. /// -- In a fight against something, the fight has value, victory has none. In a fight for something, the fight is a loss, victory merely relief. Post with compassion: http://home.chello.no/~xyzzy/kitten.jpg