220 31424 <7327f25a-3d77-4d97-808e-678b3458ee52@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: lev@compuserve.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Math constants Date: Sat, 4 Mar 2017 12:30:40 -0800 (PST) Lines: 88 Approved: news@gmane.org Message-ID: <7327f25a-3d77-4d97-808e-678b3458ee52@isocpp.org> References: <8aec2d3e-60e3-4dbf-890d-3450a32ca6d3@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1002_1497323857.1488659440206" X-Trace: blaine.gmane.org 1488659441 25645 195.159.176.226 (4 Mar 2017 20:30:41 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 4 Mar 2017 20:30:41 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCL6TUMOQUJRB4GH5TCQKGQEQCDIS7A@isocpp.org Sat Mar 04 21:30:37 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pg0-f71.google.com ([74.125.83.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ckGK3-00064L-On for gclcip-std-proposals@m.gmane.org; Sat, 04 Mar 2017 21:30:35 +0100 Original-Received: by mail-pg0-f71.google.com with SMTP id b2sf164909604pgc.6 for ; Sat, 04 Mar 2017 12:30:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=CatW40likYH7Z+yaSVQS6HQPbZ/2guYoOky45jCo19E=; b=ertuV4lVFZlVjDWvgK/xbCOHFtmKfKPfgc5Si8sdzNt/4BkVSjqmMNHmqByRU+rKCq +6ETczFP94CWlF5OagYf229gkNwfGC8TyCjXPkls6JobYg+Rv9A7fxw9fhZhp2T9zwfv MZJdZJXAG3zHwFi0txSTGuq6Or4O3Lmenz38cgB35yTVxe7tM2S0Qw42MebsPbD8usgo yisJXO+DSfE54IrdwCgp6KOwOm4+TiiMlPUnYUAHuX19fzLVhhFW2uHHU9yVnTZItDYP P2e2OETQgI1yIBpeCEs/cDTKHFAF4BUDb343c97sFW7WJaev26qb3oVS0LPEuOS6t7Jq eDfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=CatW40likYH7Z+yaSVQS6HQPbZ/2guYoOky45jCo19E=; b=QjcYq1c1FMQUK+3lMT+WqcljYWdvPPJhOUxIAOUjp95dqJHtTkH1OjZHOF0Mf6dmmG MNlIW11rY4h2m8C+G0koJoYfv3Dj9O0jxyMkOHqZ3J9aD+joXs/W0VGcMJkHyTs+qIJx oMWB8qWDCzDr/bup5RFBDI8v3znXzGJ6HdHG+1YdLtodTeWOnt7LSlq1vZZLvkvgA43o 97VV+Zube5LnUB1WUEm2/t1oHiPGDRslsg2cKkxTlEpPfVHFfcGEhI+m3iNSuwlEsmMB hbgR6v0Z2KnVwSeHAoovA9cqnsBGW2HoXbxuuBGEcKhK33uAtOyiIjybKcXGW6pH1Q/y J7+g== X-Gm-Message-State: AMke39mfNFkVFQ+eTXO/HKqQ9voo0uTmp4d+TRYxI2KRqSylzLWsZ7LS/BpW3Geg/3dfbg== X-Received: by 10.99.174.78 with SMTP id e14mr61221pgp.74.1488659441575; Sat, 04 Mar 2017 12:30:41 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.63.218 with SMTP id i26ls12698843ote.48.gmail; Sat, 04 Mar 2017 12:30:40 -0800 (PST) X-Received: by 10.157.18.133 with SMTP id g5mr872352otg.8.1488659440700; Sat, 04 Mar 2017 12:30:40 -0800 (PST) In-Reply-To: <8aec2d3e-60e3-4dbf-890d-3450a32ca6d3@isocpp.org> X-Original-Sender: lev@compuserve.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:31424 Archived-At: ------=_Part_1002_1497323857.1488659440206 Content-Type: multipart/alternative; boundary="----=_Part_1003_943666784.1488659440206" ------=_Part_1003_943666784.1488659440206 Content-Type: text/plain; charset=UTF-8 My initial line of thought was that const in this context would be equivalent to constexpr. This appears to be a gray area when it comes to implementations, so you are probably correct. Here is the revision: namespace std { constexpr long double PI = 3.14159265358979323846; // pi constexpr long double E = 2.71828182845904523536; // e constexpr long double LOG2E = 1.44269504088896340736; // log2(e) constexpr long double LOG10E = 0.434294481903251827651; // log10(e) constexpr long double LN2 = 0.693147180559945309417; // ln(2) constexpr long double LN10 = 2.30258509299404568402; // ln(10) constexpr long double SQRT2 = 1.41421356237309504880; // sqrt(2) } On Saturday, March 4, 2017 at 2:16:56 PM UTC-5, Vishal Oza wrote: > > I am not sure I would like these values written as manual constants but > rather as constexpr constants that are evaluated one during ethier > compilation or linking. This has the advantage of being as accurate at the > hardware allows while have the same runtime as a constant. -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/7327f25a-3d77-4d97-808e-678b3458ee52%40isocpp.org. ------=_Part_1003_943666784.1488659440206 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
My initial line of thought was that const in this context = would be equivalent to constexpr. This appears to be a gray area when it co= mes to implementations, so you are probably correct. Here is the revision:<= div>
namespace std {
constexpr long double PI =3D 3.= 14159265358979323846; =C2=A0 =C2=A0 =C2=A0// pi
constexpr long double E =3D 2.71828182= 845904523536; =C2=A0 =C2=A0 =C2=A0// e
constexpr long double LOG2E =3D 1.442695040888= 96340736; =C2=A0 =C2=A0 // log2(e)
constexpr long double LOG10E =3D 0.43429= 4481903251827651; // log10(e)
constexpr long double LN2 =3D 0.6931471805599= 45309417; = =C2=A0 =C2=A0 =C2=A0// ln(2)
constexpr long double LN10 =3D 2.3025850929940= 4568402; = =C2=A0 =C2=A0 =C2=A0// ln(10)
constexpr long double SQRT2 =3D 1.41421356237= 309504880; =C2=A0 =C2=A0 // sqrt(2)
}

On Saturday, March= 4, 2017 at 2:16:56 PM UTC-5, Vishal Oza wrote:
I am not sure I would like these values written as manual = constants but rather as constexpr constants that are evaluated one during e= thier compilation or linking. This has the advantage of being as accurate a= t the hardware allows while have the same runtime as a constant.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/7327f25a-3d77-4d97-808e-678b3458ee52= %40isocpp.org.
------=_Part_1003_943666784.1488659440206-- ------=_Part_1002_1497323857.1488659440206-- .