From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM
	autolearn=ham autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,13280cdb905844e4
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII
Path: 
 g2news1.google.com!postnews.google.com!j31g2000yqa.googlegroups.com!not-for-mail
From: jonathan <johnscpg@googlemail.com>
Newsgroups: comp.lang.ada
Subject: Re: Is there an Ada compiler whose
 Ada.Numerics.Generic_Elementary_Functions.Log(Base=>10,
	X=>variable) is efficient?
Date: Mon, 15 Feb 2010 06:54:56 -0800 (PST)
Organization: http://groups.google.com
Message-ID: 
 <7b3d1a4c-e61f-41c0-a35b-a9d13c6f4f67@j31g2000yqa.googlegroups.com>
References: <alpine.LNX.2.00.1002151055530.17315@Bluewhite64.example.net>
NNTP-Posting-Host: 143.117.23.62
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-Trace: posting.google.com 1266245696 638 127.0.0.1 (15 Feb 2010 14:54:56
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Mon, 15 Feb 2010 14:54:56 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: j31g2000yqa.googlegroups.com; posting-host=143.117.23.62;
	posting-account=Jzt5lQoAAAB4PhTgRLOPGuTLd_K1LY-C
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.16)
	Gecko/2009121609 Iceweasel/3.0.6 (Debian-3.0.6-3),gzip(gfe),gzip(gfe)
Xref: g2news1.google.com comp.lang.ada:9236
Date: 2010-02-15T06:54:56-08:00
List-Id: <comp.lang.ada>

On Feb 15, 10:58=A0am, Colin Paul Gloster <Colin_Paul_Glos...@ACM.org>
wrote:
> Hello,
>
> I have been improving a program by suppressing C++ in it. After
> speeding it up a lot by making changes, I have found one considerable
> part which calls a library routine, which is unfortunately very slow
> as provided as standard with a number of Ada compilers but which is
> very fast with implementations of other languages....

Here is my own bench ... easier to play with:

with ada.numerics.generic_elementary_functions;
with text_io; use text_io;

procedure log_bench is

  type Real is digits 15;
  package Math is new ada.numerics.generic_elementary_functions
(Real);
  use Math;
  x, y : Real :=3D 0.1;

  -- might (or might not!) be faster to use:
  --    log_base_10 (x) =3D log_base_10_of_e * log_base_e (x)

  Log_base_10_of_e : constant :=3D 0.434_294_481_903_251_827_651_129;

begin

  for i in 1 .. 1_000_000 loop
    x :=3D x + Log_base_10_of_e * Log (y);
    y :=3D y + 0.0000000000001;
  end loop;
  put (Real'Image(x));

end log_bench;


gnatmake  gnatnp -O2 -march=3Dnative log_bench.adb