From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.tachyum.com (mx2.tachyum.com [50.229.46.110]) by sourceware.org (Postfix) with ESMTPS id EF3D738708CE for ; Fri, 19 Feb 2021 16:44:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org EF3D738708CE Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=tachyum.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mmorrell@tachyum.com Received: by mx2.tachyum.com (Postfix, from userid 1000) id 70B7910056B9; Fri, 19 Feb 2021 08:44:04 -0800 (PST) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 Received: from THQ-EX2016.tachyum.com (thq-ex2016.tachyum.com [10.7.1.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx2.tachyum.com (Postfix) with ESMTPS id F008510056AD for ; Fri, 19 Feb 2021 08:44:03 -0800 (PST) Received: from THQ-EX3.tachyum.com (10.7.1.26) by THQ-EX2016.tachyum.com (10.7.1.16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Fri, 19 Feb 2021 08:44:03 -0800 Received: from THQ-EX2016.tachyum.com (10.7.1.16) by THQ-EX3.tachyum.com (10.7.1.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Fri, 19 Feb 2021 08:44:02 -0800 Received: from THQ-EX2016.tachyum.com ([10.7.1.16]) by THQ-EX2016.tachyum.com ([10.7.1.16]) with mapi id 15.01.1913.010; Fri, 19 Feb 2021 08:44:02 -0800 From: Michael Morrell To: "libc-alpha@sourceware.org" Subject: RE: Fix the inaccuracy of j0f/y0f/j1f/y1f Thread-Topic: Fix the inaccuracy of j0f/y0f/j1f/y1f Thread-Index: AQHXBp351p4BWcSUikGsV5rxG/VloKpfraxw Date: Fri, 19 Feb 2021 16:44:02 +0000 Message-ID: <6cf8704bcd9a45ac82cf23f05aab68a6@tachyum.com> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.0.96.10] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2021 16:44:06 -0000 I'm curious about something. Where is it specified what the required accur= acy is for a given math function? Before I discovered the libm-test-ulps f= ile, I would have expected a C library to be required to computed the exact= result for any defined function (possibly allowing some inaccuracy if -ffa= st-math were specified). I look through the POSIX spec, but couldn't find = any place that mentioned an accuracy requirement. Michael -----Original Message----- From: Libc-alpha On Behalf Of Paul Zimm= ermann Sent: Friday, February 19, 2021 1:03 AM To: libc-alpha@sourceware.org Subject: Fix the inaccuracy of j0f/y0f/j1f/y1f Hi, I just sent a new version of patches to fix #14469, #14471, #14470, #14472. Following Wilco's advice, this new version uses the "reduce_large" function= for argument reduction modulo pi/2. If anyone is willing to perform exhaustive tests on some exotic platforms, = some code is available on . Warning: it takes about one hour on a 4-core computer for each function and= each rounding mode. Paul