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=-2.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,
	MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no
	version=3.4.4
X-Google-Thread: 103376,64fc02e079586f1b
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news4.google.com!news2.google.com!proxad.net!usenet-fr.net!news.enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail
From: Marius Amado Alves <amado.alves@netcabo.pt>
Newsgroups: comp.lang.ada
Subject: Re: [Shootout] Spellcheck.adb
Date: Tue, 26 Apr 2005 00:27:29 +0100
Organization: Cuivre, Argent, Or
Message-ID: <mailman.74.1114471678.24457.comp.lang.ada@ada-france.org>
References: <1114464642.518876.137610@f14g2000cwb.googlegroups.com>
NNTP-Posting-Host: lovelace.ada-france.org
Mime-Version: 1.0 (Apple Message framework v622)
Content-Type: text/plain; charset=US-ASCII; format=flowed
Content-Transfer-Encoding: 7bit
X-Trace: melchior.cuivre.fr.eu.org 1114471679 8690 212.85.156.195 (25 Apr 2005
 23:27:59 GMT)
X-Complaints-To: usenet@melchior.cuivre.fr.eu.org
NNTP-Posting-Date: Mon, 25 Apr 2005 23:27:59 +0000 (UTC)
To: comp.lang.ada@ada-france.org
Return-Path: <amado.alves@netcabo.pt>
In-Reply-To: <1114464642.518876.137610@f14g2000cwb.googlegroups.com>
X-Mailer: Apple Mail (2.622)
X-OriginalArrivalTime: 25 Apr 2005 23:27:31.0507 (UTC)
	FILETIME=[5A3F5030:01C549EE]
X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at ada-france.org
X-BeenThere: comp.lang.ada@ada-france.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "Gateway to the comp.lang.ada Usenet newsgroup"
	<comp.lang.ada.ada-france.org>
List-Unsubscribe: <http://www.ada-france.org/mailman/listinfo/comp.lang.ada>,
	<mailto:comp.lang.ada-request@ada-france.org?subject=unsubscribe>
List-Post: <mailto:comp.lang.ada@ada-france.org>
List-Help: <mailto:comp.lang.ada-request@ada-france.org?subject=help>
List-Subscribe: <http://www.ada-france.org/mailman/listinfo/comp.lang.ada>,
	<mailto:comp.lang.ada-request@ada-france.org?subject=subscribe>
Xref: g2news1.google.com comp.lang.ada:10706
Date: 2005-04-26T00:27:29+01:00

At first sight the thing to improve is the hash function. The current 
function seems too expensive. Some time ago I had this problem. I 
invented a less expensive function with good dispersion. I don't have 
the code with me now, but it was as follows. Treat both the input and 
output values as bit strings X (1 .. M) and Y (1 .. N) respectively. 
(Use representation clauses, packed arrays, and unchecked conversion 
for this.) Make N small, say 16. Set Y bits to the value of X bits as 
follows:

if M > N, Y (J) = X (1 + (J - 1) * M / N), for J in 1 .. N

if M = N, Y = X

if M < N, initialize Y to all zeros,
  then let Y (1 + (I - 1) * N / M) = X (I), for I in 1 .. M

Another thing to improve may be the text input. Buffering with streams 
has proved faster than Text_IO.