220 31876 <582b35dc-0a1b-4a3e-92bc-881a1ef2d946@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: Wed, 29 Mar 2017 04:34:10 -0700 (PDT) Lines: 224 Approved: news@gmane.org Message-ID: <582b35dc-0a1b-4a3e-92bc-881a1ef2d946@isocpp.org> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_164_1067762707.1490787250753" X-Trace: blaine.gmane.org 1490787255 27676 195.159.176.226 (29 Mar 2017 11:34:15 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 29 Mar 2017 11:34:15 +0000 (UTC) Cc: bdawes@acm.org To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCL6TUMOQUJRBM5X53DAKGQERVI5A3Y@isocpp.org Wed Mar 29 13:34:11 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 1ctBra-0006LG-R2 for gclcip-std-proposals@m.gmane.org; Wed, 29 Mar 2017 13:34:07 +0200 Original-Received: by mail-pg0-f71.google.com with SMTP id n129sf8951928pga.0 for ; Wed, 29 Mar 2017 04:34:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc: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=2VlzPmxxyuCRAMcHBjFFYpVa8G9qOSxtIGuPphdYI94=; b=ECCDJwWQPojLNTjX7LjrM4luN82Z2A5cL5ON0aR6FdH4ZFFAjxFyq5V1n/uotk+5ns uqhHm4TqhEecvsk0d7MK0NQkaxfZZNC6QQ3ysZNMqrVyJtmnFD3HUe0J4NNVcDmEKDQ6 C+0Bgo1C7D/DBWF0aNwWzLWc+Xdh/d0102Ny0XvKs+Zp8208Omei4NUdECVgfFYqCwEl y0r1fREpqD1RZpHLt/Iu29xTHnFgYPmD4hhGd66fEZhmkW01bZNtuLdE/fXf43XTwkW/ xMX8b0EMS+xwI419+zGVsdzRRSltgXVzHPxa50N1cjOk5r+syCYVRgOiQpsyDfHVwA0y rT4Q== 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:cc: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=2VlzPmxxyuCRAMcHBjFFYpVa8G9qOSxtIGuPphdYI94=; b=dHXqnZJiAHwH7ldAgh+RpUk1R0XXip30XS9fNTZHfCwarY9h0/V092iyIsPJO0rNnN Lm56DEdhCM2Oww4oSBhzn1Sx7d1lRbk2+gBh25GH3tuTvwfeTNe0t2Zul5XW6dMLvnia GYydok3/70hzyfHz2yX/Gn+cO/HqK5beEFEd2SCq2oVlBmyFbXms7sLN2b7NBpcnvPUW 22ok600nmXemAJDbMe6GqG4u/XGnsj8BtA6y2klz1S8pnWkYSO+6qFPtgjrKbzgb0x1Q hLIsn3vdJ59wDQr4NCvXHxhBMkH8kvF/o9/HJ0pEJ+p9JEIggoBwqbXnYLB5dXb+Ntul D9Rg== X-Gm-Message-State: AFeK/H11TcwLSKVPznLi1jYDrH1CpQDJjBQrpEfJX2kVK7NbjLyTMkaFy+zQU1n68g8u8Q== X-Received: by 10.98.139.154 with SMTP id e26mr1181pfl.30.1490787252639; Wed, 29 Mar 2017 04:34:12 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.42.168 with SMTP id e37ls12015846otb.3.gmail; Wed, 29 Mar 2017 04:34:11 -0700 (PDT) X-Received: by 10.157.11.150 with SMTP id 22mr447oth.18.1490787251562; Wed, 29 Mar 2017 04:34:11 -0700 (PDT) In-Reply-To: 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:31876 Archived-At: ------=_Part_164_1067762707.1490787250753 Content-Type: multipart/alternative; boundary="----=_Part_165_1484881662.1490787250753" ------=_Part_165_1484881662.1490787250753 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Beman, =20 Thank you for your message. Yes, I am aware of the good work= =20 that Boost contributors have done on Boost constants. It doesn=E2=80=99t su= rprise=20 me that math functions are difficult to implement in a true cross-platform= =20 and computationally stable way. I spoke with Paul Bristow via email and got= =20 some useful feedback from him.=20 =20 The goal of my proposal is far more narrow. I focus=20 specifically on constants, and explicitly state that several aspects of=20 their implementation should be left up to the implementer=E2=80=99s discret= ion. It=20 is not my intent at all to compile a comprehensive set of math constants. I= =20 merely want to =E2=80=9Cpush downstream=E2=80=9D the set included in severa= l derivative=20 standardization efforts. =20 - Lev=20 On Wednesday, March 29, 2017 at 7:04:35 AM UTC-4, Beman Dawes wrote: > > > > On Sat, Mar 4, 2017 at 1:32 PM, > wrote= : > >> >> >> *Hello everyone, Many areas of software development where C++ is= =20 >> actively used involve mathematical calculations. The language inherited = a=20 >> sizable math function library from C, and now has its own numerics libra= ry=20 >> that grows with every release. There is however a small but annoying=20 >> omission: C++ standard headers do not include definitions of mathematica= l=20 >> constants. To this math major it appears to be a very strange gap: where= ver=20 >> common mathematical functions are used, the constants such as =CF=80 or= e=20 >> appear quite frequently. Yes, it is not terribly difficult to define a= =20 >> constant, but from the C++ user's perspective this is as if they were=20 >> served a dish at a restaurant but asked to bring their own salt. * >> > > Hi Lev, > > Are you aware of=20 > www.boost.org/doc/libs/1_63_0/libs/math/doc/html/constants.html ? > > IIRC, development of a truly useful library of C++ math functions was far= =20 > more complex than anyone would have guessed at the onset, and took severa= l=20 > years of effort. You might want to talk to John Maddock, Paul Bristow,=20 > and Christopher Kormanyos first. > > --Beman > > --=20 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 e= mail 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/582b35dc-0a1b-4a3e-92bc-881a1ef2d946%40isocpp.or= g. ------=_Part_165_1484881662.1490787250753 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

<= span style=3D"font-size:11.0pt; font-family:"Calibri",sans-serif;mso-ascii-theme-font:minor-latin= ;mso-hansi-theme-font: minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme= -font:minor-bidi">Hi Beman,

=C2=A0

=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0 Thank you for your message. Yes, I am aware of the good work that Boost contributors have done on Boost consta= nts. It doesn=E2=80=99t surprise me that math functions are difficult to impleme= nt in a true cross-platform and computationally stable way. I spoke with Paul Bristow vi= a email and got some useful feedback from him.

=C2=A0

=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0 The goal of my proposal is far more narrow. I focus specifically on constants, and explicitly state that severa= l aspects of their implementation should be left up to the implementer=E2=80=99s disc= retion. It is not my intent at all to compile a comprehensive set of math constants. I merely want to =E2=80=9Cpush downstream=E2=80=9D the set included in severa= l derivative standardization efforts.

=C2=A0

  • Lev

On Wednesday, March 29, 2017 at 7:04:35 AM UTC-4, Beman Dawes wrot= e:

On Sat, Mar 4, 2017 at 1:32 PM, <l...@compuserve.com> wrote:
Hello everyone,
=

=C2=A0 =C2=A0 =C2=A0 =C2=A0 Many areas of software deve= lopment where C++ is actively used involve mathematical calculations. The l= anguage inherited a sizable math function library from C, and now has its o= wn numerics library that grows with every release. There is however a small= but annoying omission: C++ standard headers do not include definitions of = mathematical constants. To this math major it appears to be a very strange = gap: wherever common mathematical functions are used, the constants such as= =C2=A0=CF=80 or e appear quite frequently. Yes, it is not terribly difficu= lt to define a constant, but from the C++ user's perspective this is as= if they were served a dish at a restaurant but asked to bring their own sa= lt.=C2=A0


<= div>Hi Lev,


IIRC, development of a truly useful library of C++ math fun= ctions was far more complex than anyone would have guessed at the onset, an= d took several years of effort. You might want to talk to John Maddock, Pau= l Bristow, and=C2=A0Christopher Kormanyos first.

-= -Beman

--
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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/582b35dc-0a1b-4a3e-92bc-881a1ef2d946= %40isocpp.org.
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