Path: csiph.com!x330-a1.tempe.blueboxinc.net!newsfeed.hal-mli.net!feeder3.hal-mli.net!nx02.iad01.newshosting.com!newshosting.com!69.16.185.16.MISMATCH!npeer02.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!border3.nntp.dca.giganews.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.earthlink.com!news.earthlink.com.POSTED!not-for-mail NNTP-Posting-Date: Mon, 08 Aug 2011 07:37:13 -0500 Date: Mon, 08 Aug 2011 05:37:12 -0700 From: Patricia Shanahan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.18) Gecko/20110616 Thunderbird/3.1.11 MIME-Version: 1.0 Newsgroups: comp.lang.java.programmer Subject: Re: higher precision doubles References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Message-ID: Lines: 51 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 70.230.203.65 X-Trace: sv3-GaTl1C86RX4YuLg+ePnbijosnsYPjGa4ZNkLDghXfYRqU2xhrK9Yp3Q06VrUB4yuXcv2Lodt1/R2z0X!AKzq2GArkB/3ao4MX3b49KpZm7IYgdX7AIdq44s2F+iBea4HjS9X9I8WMxKkK2Zu/xOaSXVB3gq/!q2NLRi6dWxVyJN1gCedORZIWctRvBlQaOrYb9Q1C73t7Lw== X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 3828 Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:6867 On 8/8/2011 12:05 AM, Jan Burse wrote: > Eric Sosman schrieb: >>> 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? >> >> You have already said "So pointing me to JLS is like turning >> cycles, only confirming that Java has only float and double." That >> is, the JLS has already given you an answer -- but you don't like >> the answer, and keep asking for a different one. Do you really >> think your persistent rejection of "No" is productive? > > > You are the first one that says "no". One could of > course do something along the following lines: > > public class DoubleExt { > private long mantissa; > private short exponent; > } > > And then make a package that interfaces with some > of the known C libs for 80bit floats. > > But would this be considered the best practice? Whether it is best practice, or even practical, depends on the characteristics of the code that needs extended precision. If the extended precision arithmetic comes in fairly isolated chunks, so that you can afford significant overhead for each chunk, you could indeed write some part of the application in Java and still do the extended precision arithmetic in another language. For comparison, my doctoral dissertation research used a program that did a lot of general computation that I needed to be able to change rapidly, and some big blocks of linear algebra. I did the linear algebra in Matlab, because it had exactly the functions I needed, but the rest of the program was in Java. If the extended precision arithmetic is scattered uniformly throughout the program, and there is too much of it to do it in software emulation, you need to write the whole program in a language that supports hardware extended precision. This is why I have been trying to find out more about the application or applications that need the extended precision arithmetic - it is difficult to suggest solutions without knowing a bit about the requirements. Patricia