From mboxrd@z Thu Jan  1 00:00:00 1970
X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/13984
Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail
From: Szabolcs Nagy <nsz@port70.net>
Newsgroups: gmane.linux.lib.musl.general
Subject: Re: Re: atanhf(x) Slight Accuracy Improvements
Date: Mon, 18 Mar 2019 00:07:30 +0100
Message-ID: <20190317230729.GQ26605@port70.net>
References: <alpine.LRH.2.02.1903132105140.4826@key0.esi.com.au>
 <alpine.LRH.2.02.1903151222160.13162@key0.esi.com.au>
 <alpine.LRH.2.02.1903172219370.6962@key0.esi.com.au>
Reply-To: musl@lists.openwall.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226";
	logging-data="248551"; mail-complaints-to="usenet@blaine.gmane.org"
User-Agent: Mutt/1.10.1 (2018-07-13)
To: musl@lists.openwall.com
Original-X-From: musl-return-14000-gllmg-musl=m.gmane.org@lists.openwall.com Mon Mar 18 00:07:49 2019
Return-path: <musl-return-14000-gllmg-musl=m.gmane.org@lists.openwall.com>
Envelope-to: gllmg-musl@m.gmane.org
Original-Received: from mother.openwall.net ([195.42.179.200])
	by blaine.gmane.org with smtp (Exim 4.89)
	(envelope-from <musl-return-14000-gllmg-musl=m.gmane.org@lists.openwall.com>)
	id 1h5esa-0012RE-Ri
	for gllmg-musl@m.gmane.org; Mon, 18 Mar 2019 00:07:44 +0100
Original-Received: (qmail 31993 invoked by uid 550); 17 Mar 2019 23:07:42 -0000
Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm
Precedence: bulk
List-Post: <mailto:musl@lists.openwall.com>
List-Help: <mailto:musl-help@lists.openwall.com>
List-Unsubscribe: <mailto:musl-unsubscribe@lists.openwall.com>
List-Subscribe: <mailto:musl-subscribe@lists.openwall.com>
List-ID: <musl.lists.openwall.com>
Original-Received: (qmail 31975 invoked from network); 17 Mar 2019 23:07:42 -0000
Mail-Followup-To: musl@lists.openwall.com
Content-Disposition: inline
In-Reply-To: <alpine.LRH.2.02.1903172219370.6962@key0.esi.com.au>
Xref: news.gmane.org gmane.linux.lib.musl.general:13984
Archived-At: <http://permalink.gmane.org/gmane.linux.lib.musl.general/13984>

* Damian McGuckin <damianm@esi.com.au> [2019-03-17 22:41:53 +1100]:
> ATANH(x)  From  .. To      WORST ERROR  % ERROR>EPS/2  MEAN ERROR
> 
> Improved:0.00000..0.00012  0.04027*EPS   0.00000%      0.00301*EPS
> Original:0.00000..0.00012  0.99741*EPS   0.39818%      0.00581*EPS
> 
> Improved:0.00012..0.00100  0.66667*EPS   8.86075%      0.21559*EPS
> Original:0.00012..0.00100  0.95814*EPS   7.42942%      0.21211*EPS
> 
> Improved:0.00100..0.17157  0.55526*EPS   0.00605%      0.17453*EPS
> Original:0.00100..0.17157  1.09363*EPS   8.51956%      0.23306*EPS
> 
> Improved:0.17157..0.18248  0.63539*EPS   0.41833%      0.18648*EPS
> Original:0.17157..0.18248  1.07990*EPS   5.23646%      0.21706*EPS
> 
> Improved:0.18248..0.26667  0.83800*EPS   2.10627%      0.18376*EPS
> Original:0.18248..0.26667  1.12385*EPS   8.71681%      0.23764*EPS
> 
> Improved:0.26667..0.55000  0.90005*EPS   3.97403%      0.20866*EPS
> Original:0.26667..0.55000  1.12779*EPS   9.27245%      0.24201*EPS
> 
> Improved:0.55000..1.00000  0.68372*EPS   1.39651%      0.19197*EPS
> Original:0.55000..1.00000  0.68372*EPS   1.40897%      0.19207*EPS
> 
> Does this sort of gain make it worthwhile pursing a double version?

if you improve accuracy without performance loss that sounds
useful, but i cannot comment on it without seeing the patch.