[{"id":1798053,"web_url":"http://patchwork.ozlabs.org/comment/1798053/","msgid":"<39c1c9db-fc34-d1e9-e8ce-8ab2dedbe73b@gmail.com>","list_archive_url":null,"date":"2017-11-02T16:09:58","subject":"Re: [PATCHv3] New generic sinf","submitter":{"id":69753,"url":"http://patchwork.ozlabs.org/api/people/69753/","name":"Manfred","email":"mx2927@gmail.com"},"content":"On 11/2/2017 4:50 PM, Rajalakshmi Srinivasaraghavan wrote:\n> +static inline float\n> +reduced (const double theta, const unsigned long n,\n> +\t const unsigned long signbit)\n> +{\n> + double sx;\n> + const double theta2 = theta * theta;\n> + /* We are operating on|x|, so we need to add back the original\n> + * signbit for sinf. */\n> + int sign;\n> + sign = ones[((n >> 2) & 1) ^ signbit];\n> + theta2 = theta * theta;\nIsn't the above a duplication?\n\n> + /* Chebyshev polynomial of the form for sin:\n> + * x+x^3*(S0+x^2*(S1+x^2*(S2+x^2*(S3+x^2*S4)))).\nIsn't the following an expansion for cos?\n> + * 1.0+x^2*(C0+x^2*(C1+x^2*(C2+x^2*(C3+x^2*C4)))). */","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":["patchwork-incoming@bilbo.ozlabs.org","mailing list libc-alpha@sourceware.org"],"Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=sourceware.org\n\t(client-ip=209.132.180.131; helo=sourceware.org;\n\tenvelope-from=libc-alpha-return-86680-incoming=patchwork.ozlabs.org@sourceware.org;\n\treceiver=)","ozlabs.org; dkim=pass (1024-bit key;\n\tsecure) header.d=sourceware.org header.i=@sourceware.org\n\theader.b=\"EIc8ykOI\"; dkim-atps=neutral","sourceware.org; auth=none"],"Received":["from sourceware.org (server1.sourceware.org [209.132.180.131])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256\n\tbits)) (No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3ySVRV6hKcz9t2V\n\tfor ;\n\tFri, 3 Nov 2017 03:10:14 +1100 (AEDT)","(qmail 55389 invoked by alias); 2 Nov 2017 16:10:09 -0000","(qmail 55376 invoked by uid 89); 2 Nov 2017 16:10:08 -0000"],"DomainKey-Signature":"a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id\n\t:list-unsubscribe:list-subscribe:list-archive:list-post\n\t:list-help:sender:subject:to:references:from:message-id:date\n\t:mime-version:in-reply-to:content-type\n\t:content-transfer-encoding; q=dns; s=default; b=tRvVYdijqXq9dKRF\n\toxfvf3S9nJihznz4hZwP89m+WmqWTztS87Ih3TifPMYVNVBqsybo1XJh9sABVPwT\n\tPRdsfWjNG7zI28rj/6SevkFGkpeqG097aOyMrvPbP2WsZwYbykLWmXnaPhTt2D44\n\tsV0XuWDNRtS+ea/fO116wk1zdr4=","DKIM-Signature":"v=1; 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a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:subject:to:references:from:message-id:date\n\t:user-agent:mime-version:in-reply-to:content-language\n\t:content-transfer-encoding;\n\tbh=mEOUJaayGmsPIEsd29o7TtlUKDChw0xyVsg0Y5F13Bk=;\n\tb=HhuugYafEIqzeAQSWQaO+ZVHkI2y1KJpjx4tBrSqrhPe+pVgxLiDco+1CEJ3ZqBlnV\n\tici2809N+fXdbXvJwlGKX+5UI7396fj3r46y94e9rZHMNPa0yVGh3PoR0Ho/uY543ldt\n\tq4J6o5qcXFSBFIUbG1AgO5FKC3krWlfDvamearMKysU/2pcWTpecd0Zfy57JYJuYUggU\n\toSfxAQI22CjQfXXvHTonZgMnLv2g6Aze558BvXlfpHY7Iixjj/47xqrpIDjaY7FKzz0l\n\toI4rp0DJhWOfq2oS3TxmoQWHfW3Z222Zaw1wEoeOfKH0JCWRypSs4V0CATXbA4CB2QRc\n\tf75Q==","X-Gm-Message-State":"AMCzsaWkizZdXXQQN21Bt1nxRrfM7vDglkpoYf5eEBpBtLCbYAXXv7kO\n\tD667tNe3edQp1KFK2hMbeSL+qw==","X-Google-Smtp-Source":"ABhQp+S4wq0BkS4EC7DPF9FBT2AabSNNh8P3pyx5hG7JPjYSRTHQXh+Tsut0ts7OyduI47ut9su1mw==","X-Received":"by 10.46.16.218 with SMTP id 87mr1931712ljq.115.1509639001201;\n\tThu, 02 Nov 2017 09:10:01 -0700 (PDT)","Subject":"Re: [PATCHv3] New generic sinf","To":"libc-alpha@sourceware.org","References":"<1509637838-21839-1-git-send-email-raji@linux.vnet.ibm.com>","From":"Manfred ","Message-ID":"<39c1c9db-fc34-d1e9-e8ce-8ab2dedbe73b@gmail.com>","Date":"Thu, 2 Nov 2017 17:09:58 +0100","User-Agent":"Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101\n\tThunderbird/52.4.0","MIME-Version":"1.0","In-Reply-To":"<1509637838-21839-1-git-send-email-raji@linux.vnet.ibm.com>","Content-Type":"text/plain; charset=utf-8; format=flowed","Content-Transfer-Encoding":"7bit"}},{"id":1798089,"web_url":"http://patchwork.ozlabs.org/comment/1798089/","msgid":"","list_archive_url":null,"date":"2017-11-02T17:00:11","subject":"Re: [PATCHv3] New generic sinf","submitter":{"id":4349,"url":"http://patchwork.ozlabs.org/api/people/4349/","name":"Joseph Myers","email":"joseph@codesourcery.com"},"content":"On Thu, 2 Nov 2017, Rajalakshmi Srinivasaraghavan wrote:\n\n> +/* reduced (theta, n, signbit):\n> + * Compute sine (n * theta) using Chebyshev polynomials, where\n> + * - -Pi/4 <= theta < Pi/4\n> + * - n thus indicates the actual quadrant in which n*theta resides.\n> + * n is used to decide whether a sine or cosine approximation is\n> + * more accurate and the sign of the result. */\n\nGNU standard does not have the leading '*' on each line of the comment, \nand does not repeat the function name / prototype in the comment; the \nvalues of arguments should be referred to in uppercase in the comment.\n\nAnd this function certainly isn't computing sin (n * theta), there's no \nmultiplication by n involved. I think it might actually be something like \nsin (((-1)**SIGNBIT) * (THETA + (N >> 1)*PI/2)), but the comment needs to \nstate this, or whatever the actual function calculated is, explicitly \n(along with the constraint on the range for THETA).","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":["patchwork-incoming@bilbo.ozlabs.org","mailing list libc-alpha@sourceware.org"],"Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=sourceware.org\n\t(client-ip=209.132.180.131; helo=sourceware.org;\n\tenvelope-from=libc-alpha-return-86681-incoming=patchwork.ozlabs.org@sourceware.org;\n\treceiver=)","ozlabs.org; dkim=pass (1024-bit key;\n\tsecure) header.d=sourceware.org header.i=@sourceware.org\n\theader.b=\"Pg+Y+B99\"; dkim-atps=neutral","sourceware.org; auth=none"],"Received":["from sourceware.org (server1.sourceware.org [209.132.180.131])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256\n\tbits)) (No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3ySWYb5mv9z9s83\n\tfor ;\n\tFri, 3 Nov 2017 04:00:35 +1100 (AEDT)","(qmail 80622 invoked by alias); 2 Nov 2017 17:00:27 -0000","(qmail 80048 invoked by uid 89); 2 Nov 2017 17:00:21 -0000"],"DomainKey-Signature":"a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id\n\t:list-unsubscribe:list-subscribe:list-archive:list-post\n\t:list-help:sender:date:from:to:cc:subject:in-reply-to:message-id\n\t:references:mime-version:content-type; q=dns; s=default; b=w1DX+\n\tR4AOhqCVzxLxYAtGbHjA5G9my7dMbLoKrLVMceFVgc5jVGJZYiC/9/dovDRncY0A\n\tsxrUEb1s9ri8u4ihlmEdz8oyM+pFJ1h/oqL8bdFG6EXYbGPzx5CX4akD76BwmnlN\n\tYaqfVlV4de64HVTYsnmj6nX28YsWZLVHqBeCoM=","DKIM-Signature":"v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id\n\t:list-unsubscribe:list-subscribe:list-archive:list-post\n\t:list-help:sender:date:from:to:cc:subject:in-reply-to:message-id\n\t:references:mime-version:content-type; s=default; bh=Nz++FGQnqwu\n\ta9Ns0AtnLI5d8LYI=; b=Pg+Y+B99IEUPpJpuOYRgP0KBisUUXRBkPMBKxY9+Mtq\n\tDqATtqmHiLaSqMamzXKFFvYRrGgyCQCCZY5/4l5inNKtej1+SY8iBpHPs0cfAg9g\n\tvqsYeijru9L7k1ZN23bGLK0PGv6uwLhscoSjU6ZfCxw6xHAqWyudXbUGQPEqSI+8\n\t=","Mailing-List":"contact libc-alpha-help@sourceware.org; run by ezmlm","Precedence":"bulk","List-Id":"","List-Unsubscribe":"","List-Subscribe":"","List-Archive":"","List-Post":"","List-Help":",\n\t","Sender":"libc-alpha-owner@sourceware.org","X-Virus-Found":"No","X-Spam-SWARE-Status":"No, score=-2.0 required=5.0 tests=AWL, BAYES_00,\n\tRCVD_IN_DNSWL_NONE, SPF_PASS,\n\tURIBL_RED autolearn=ham version=3.3.2 spammy=Hx-languages-length:1012","X-HELO":"relay1.mentorg.com","Date":"Thu, 2 Nov 2017 17:00:11 +0000","From":"Joseph Myers ","To":"Rajalakshmi Srinivasaraghavan ","CC":"","Subject":"Re: [PATCHv3] New generic sinf","In-Reply-To":"<1509637838-21839-1-git-send-email-raji@linux.vnet.ibm.com>","Message-ID":"","References":"<1509637838-21839-1-git-send-email-raji@linux.vnet.ibm.com>","User-Agent":"Alpine 2.20 (DEB 67 2015-01-07)","MIME-Version":"1.0","Content-Type":"text/plain; charset=\"US-ASCII\"","X-ClientProxiedBy":"svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) To\n\tSVR-IES-MBX-03.mgc.mentorg.com (139.181.222.3)"}}]