Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.albasani.net!.POSTED!not-for-mail From: Jan Burse Newsgroups: comp.lang.java.programmer Subject: Re: higher precision doubles Date: Sun, 07 Aug 2011 21:23:03 +0200 Organization: albasani.net Lines: 47 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news.albasani.net 1KbueUWJd44edcbMfHazJCKqd0CvLLbac1OGf/9EFwzE8y1lG+NFJWUEEqnfA8axZfXloupTz05Zo20+6BtP7Q== NNTP-Posting-Date: Sun, 7 Aug 2011 19:23:04 +0000 (UTC) Injection-Info: news.albasani.net; logging-data="npZF4sF2VSwXvYfWJRd0UzuMPS5ycjPuK+kFqqhN0ydtTL8SDGoSyuQZhJ3uGecPZOyRRNnkZv4P2EOe6F29gHfbPZFEao8EaW9Wl26G3qgdkQUpOmL9SPBsalpcwa2f"; mail-complaints-to="abuse@albasani.net" User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:5.0) Gecko/20110706 Firefox/5.0 SeaMonkey/2.2 In-Reply-To: Cancel-Lock: sha1:SmTtUNG9JuF7a8VyXUPZX6oPSGs= Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:6857 Patricia Shanahan schrieb: > One can often make some particular combination of calculations give a > more precise answer by some variations in the arithmetic. However, this > does not give much indication of the real requirements. > > Do calculations involving trig functions of integer multiples of pi need > to be exact in some application, even if trig functions of other angles > have normal rounding behavior? If so, why? Or do you need trig functions > in general to be more precise? I guess you looking too far. The higher precision is just parameter of the representation. From a far angel we have the requirement that float fit into 32 bit and double into 64 bit. In my post 06.08.2011 13:03 I was writing: > I was wondering whether I can take advantage of an AMD64. Since > it has 80bit IEEE floating point registers: > > http://people.freebsd.org/~lstewart/references/amd64.pdf > Paragraph 1.2 So no need to show you any application. I am just interested in the 80 bit. Whether I CAN work with them or not. I am not interested in the question whether I SHOULD work with them. In my post 06.08.2011 00:20, I was asking this as follows: > IEEE allows to internally calculate with additional bits. > Is it possible to have awailable these ops? Like an add > with this higher precision? How could we store such a > result? Would there be a wrapper like Double? We can also dig a little bit further what the representation parameters are. In particular we have: Mantissa Exponent double 64bit: 52 bit 11 bit double 80bit: 64 bit 15 bit So here I can restate my question: I would like for whatever reason work with 80bit floats as defined above in Java. I am interested in the full set of arithmetic functions, I/O and trigonometric functions. How could I do that? Best Regards