From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11028 Path: news.gmane.org!.POSTED!not-for-mail From: James Cloos Newsgroups: gmane.linux.lib.musl.general Subject: catrig Date: Sat, 11 Feb 2017 23:59:46 -0500 Message-ID: Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1486875611 25398 195.159.176.226 (12 Feb 2017 05:00:11 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 12 Feb 2017 05:00:11 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) To: musl@lists.openwall.com Original-X-From: musl-return-11043-gllmg-musl=m.gmane.org@lists.openwall.com Sun Feb 12 06:00:05 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1ccmGY-00063x-LL for gllmg-musl@m.gmane.org; Sun, 12 Feb 2017 06:00:02 +0100 Original-Received: (qmail 15590 invoked by uid 550); 12 Feb 2017 05:00:06 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 15561 invoked from network); 12 Feb 2017 05:00:04 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jhcloos.com; s=ore14; t=1486875591; bh=eecY9PbiStfAvLVrly3fG7kYuXtICyy7PyAe471J7+w=; h=From:To:Subject:Date:From; b=jfJ+jcl11Ft2bvqa6iGNb/SCE/eGzjOzLcPM8WzVPbtE++k+e9LctohsYXnPL9rMS F0oV/jdmMsNKU2OuU3RV3xAlU+wJVWE0CqwzxUWOYdoWXtPTjUxU3ZmN6skFeu65R5 DXejyhQzDdgRTB+OHcBp8mRJtEe52mKzuj+wleyY= Face: iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAgMAAABinRfyAAAACVBMVEX///8ZGXBQKKnCrDQ3 AAAAJElEQVQImWNgQAAXzwQg4SKASgAlXIEEiwsSIYBEcLaAtMEAADJnB+kKcKioAAAAAElFTkSu QmCC Copyright: Copyright 2016 James Cloos OpenPGP: 0x997A9F17ED7DAEA6; url=https://jhcloos.com/public_key/0x997A9F17ED7DAEA6.asc OpenPGP-Fingerprint: E9E9 F828 61A4 6EA9 0F2B 63E7 997A 9F17 ED7D AEA6 Original-Lines: 26 Xref: news.gmane.org gmane.linux.lib.musl.general:11028 Archived-At: There was a recent post on one of the freebsd lists about Stephen Montgomery-Smith's catrig routines: http://faculty.missouri.edu/~stephen/software/#catrig which is based on the paper "Implementing the complex arcsine and arccosine functions using exception handling" by T. E. Hull, Thomas F. Fairgrieve, and Ping Tak Peter Tang, published in ACM Transactions on Mathematical Software, Volume 23 Issue 3, 1997, Pages 299-335, http://dl.acm.org/citation.cfm?id=275324. It looks to be the most accurate catrig code availalbe. Stephen writes that tests indicate that both the real and imaginary parts of the results are good to within 4 ULP, that catrigl.c supports both 80 bit and 128 bit long double but that the float version is occasionally slightly worse that 4 ULP. I don't know how much interest the musl community has in better accuracy for libm, but in case there is interest Stephen's code looks like a good choice. And I see musl already uses freebsd libm code for some of the complex trig. -JimC -- James Cloos OpenPGP: 0x997A9F17ED7DAEA6