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Newsgroups: comp.lang.ada
Date: Thu, 15 Oct 2015 04:23:39 -0700 (PDT)
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Subject: Re: Issue with SPARK 2014
From: Stuart <google_news@palin-26.freeserve.co.uk>
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Xref: news.eternal-september.org comp.lang.ada:27981
Date: 2015-10-15T04:23:39-07:00
List-Id: <comp.lang.ada>

On Thursday, 15 October 2015 09:44:39 UTC+1, Phil Thornley  wrote:
...
> Stuart's explanation is quite correct.
[Thank you :-)]

> In the first version try changing the bound on Count1 to:
>    Integer (Columns'Pred (Column) - J)
> so that it starts at 0 and increments by 1 on each loop.
...
Having thought about it a bit more (but still no opportunity to test) I thought that example 1 could use the invariant:
   Count1 = Integer(J-Columns'First)

This seems to capture the essence of the loop (always a good sign for a loop invariant)

In the absence of the full code getting a definitive useful loop invariant is not possible!