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Date: Mon, 11 Mar 2002 13:48:34 -0600
From: Anatoly Chernyshev <rhezusfactor@yahoo.com>
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Subject: Re: I think - it's a bug...
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Thanks to everyone who tried to answer this post.
Eventually, I've found a solution that always put me on the safe side:

replace
FOR k IN 0..integer(b/dz) LOOP
with
FOR K IN 0..Integer(Float'Truncation(B/Dz)) LOOP

Anatoly Chernyshev wrote:

> Look at this piece of code:
>
> -------------------------------------------------------------------------------------------------
>
> WITH ada.text_io,ada.numerics.elementary_functions;
> USE ada.text_io, ada.numerics.elementary_functions;
> PROCEDURE el_stat_fun IS
>    b            : float := 7.5;
>    a:float:=4.0;
>    rr, z : float;
>    r            : float := 4.0;
>    dz           : float := 0.3;
> BEGIN
>    FOR k IN 0..integer(b/dz) LOOP
>       z:=float(k)*dz;
>       put_line (float'image(1.0-(z/b)));
>       rr:=-a*sqrt((1.0-(z/b)**2))+a+r;
>    END LOOP;
> END el_stat_fun;
> ----------------------------------------------------------------------------------------------------
>
> When compiled using GNAT 3.14 (WinNT sp 6) it raises
> ADA.NUMERICS.ARGUMENT_ERROR in sqrt function when k goes to 25 because
> the argument for sqrt becomes
> negative (like -X.XXXXXE-07 ... And this is a headache No 1).
> However, if one comments out the put_line string - everything works
> fine.
>
> I don't know whether this is a bug or feature, but any kind of help for
> how to avoid the situation when 1.0-1.0/1.0 yields  something different
> from 0.0 will be greatly appreciated.
>
> Thanks in advance,
>
> Anatoly.