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=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,d45251e6e639e463
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Received: by 10.68.238.65 with SMTP id vi1mr154152pbc.7.1340840282918;
        Wed, 27 Jun 2012 16:38:02 -0700 (PDT)
Path: 
 l9ni27475pbj.0!nntp.google.com!news1.google.com!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
From: Shark8 <onewingedshark@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: questions on using the array component iterator for 2012
Date: Wed, 27 Jun 2012 16:31:33 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: <ac03aab4-11cd-4904-a5dc-d09aa96cb9e6@googlegroups.com>
References: <js4b8m$21r$1@speranza.aioe.org>
NNTP-Posting-Host: 96.2.54.122
Mime-Version: 1.0
X-Trace: posting.google.com 1340840282 19258 127.0.0.1 (27 Jun 2012 23:38:02
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Wed, 27 Jun 2012 23:38:02 +0000 (UTC)
Cc: nma@12000.org
In-Reply-To: <js4b8m$21r$1@speranza.aioe.org>
Complaints-To: groups-abuse@google.com
Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=96.2.54.122;
 posting-account=lJ3JNwoAAAAQfH3VV9vttJLkThaxtTfC
User-Agent: G2/1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
Date: 2012-06-27T16:31:33-07:00
List-Id: <comp.lang.ada>

On Saturday, June 23, 2012 7:02:18 AM UTC-5, Nasser M. Abbasi wrote:
> For example, assume I write
>     FOR e of A  LOOP
>         e :=3D e + 1 ;
>     END LOOP
> [...]
>=20
> But suppose I want to implement say a Jacobi relaxation
> iteration to solve a 2D Laplace pde on that grid, which
> is defined to update each element in the grid using
>=20
> A(i,j) :=3D (1/4) (  A(i-1,j)+A(i+1,j)+A(i,j-1)+A(i,j+1)
>=20
> where here 'i' is row index, and 'j' is column index.

Well the problem is that the "FOR E IN ..." loop is conceptually different =
from a "FOR Index IN Array_Variable'RANGE" loop. The difference is that in =
the former you don't care what the index/indices are, you just want to appl=
y the same procedure to each element.

Given that needing the index is sometimes wanted, the designers may have ad=
ded a 'Index(X) attribute, I don't really know because I've not had the inc=
lination to explore the new loop in such depth.