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From: robert_dewar@my-dejanews.com
Subject: Re: Calculating SQRT in ADA
Date: 1999/03/25
Date: 1999-03-25T00:00:00+00:00	[thread overview]
Message-ID: <7dei54$dv2$1@nnrp1.dejanews.com> (raw)
In-Reply-To: 19990324201959.00800.00000708@ngol04.aol.com

In article <19990324201959.00800.00000708@ngol04.aol.com>,
  johnherro@aol.com (John Herro) wrote:
> Robert Dewar wrote:
> >>   while ...
> >>        abs(Guess*Guess/X - 1.0) > 3.0*Dummy'Epsilon
loop
> > Why the epsilon test, this iteration will terminate to
> > exact equality in any reasonable floating-point model
...
>
> I don't know if the Open Ada 83 compiler has a
"reasonable" floating-point
> model, but I do know that if I test for exact equality,
instantiate with type
> Float, and compute Sqrt(2.0) with that compiler, the
program goes into an
> infinite loop.  I think that in general, you can't
guarantee that Guess*Guess
> will ever exactly equal X.


Of course not!

The proper way for testing for convergence is to see if
the new guess is the same as the last guess!

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  parent reply	other threads:[~1999-03-25  0:00 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-03-24  0:00 Calculating SQRT in ADA cmcrae
1999-03-23  0:00 ` Chris Morgan
1999-03-24  0:00   ` Marin David Condic
     [not found]   ` <36F913E0.75F51763@lmco.com>
1999-03-24  0:00     ` John Herro
1999-03-24  0:00       ` Hans Marqvardsen
     [not found]         ` <36FAA3DF.42C31CF@lmco.com>
1999-03-26  0:00           ` Tom Moran
1999-03-25  0:00       ` robert_dewar
1999-03-25  0:00         ` John Herro
1999-03-24  0:00           ` Hans Marqvardsen
1999-03-25  0:00             ` David C. Hoos, Sr.
1999-03-25  0:00           ` robert_dewar [this message]
1999-03-26  0:00             ` Calculating SQRT in Ada John Herro
1999-03-26  0:00               ` David C. Hoos, Sr.
1999-03-26  0:00                 ` John Herro
1999-03-25  0:00           ` Calculating SQRT in ADA robert_dewar
1999-03-25  0:00             ` David C. Hoos, Sr.
1999-03-26  0:00               ` Howard W. LUDWIG
1999-03-26  0:00             ` Ole-Hjalmar Kristensen
1999-03-27  0:00               ` robert_dewar
1999-03-29  0:00                 ` Robert I. Eachus
1999-03-30  0:00                   ` robert_dewar
1999-04-02  0:00                     ` Robert I. Eachus
1999-03-30  0:00                   ` robert_dewar
1999-04-02  0:00                     ` Robert I. Eachus
1999-04-03  0:00                       ` robert_dewar
1999-03-25  0:00       ` robert_dewar
1999-03-24  0:00     ` Ada 83 - Sometimes still chosen Richard D Riehle
1999-03-25  0:00       ` robert_dewar
1999-03-25  0:00         ` Richard D Riehle
1999-03-25  0:00           ` Marin David Condic
1999-03-26  0:00           ` robert_dewar
1999-03-25  0:00       ` robert_dewar
1999-03-25  0:00         ` Richard D Riehle
1999-03-25  0:00           ` Larry Kilgallen
1999-03-26  0:00           ` robert_dewar
1999-03-26  0:00             ` Tom Moran
1999-03-26  0:00             ` Richard D Riehle
1999-03-26  0:00               ` Tom Moran
1999-03-26  0:00                 ` Larry Kilgallen
1999-03-29  0:00                 ` Marin David Condic
1999-03-29  0:00                   ` Tarjei Tj�stheim Jensen
1999-03-27  0:00               ` Matthew Heaney
1999-03-26  0:00             ` Tarjei Tj�stheim Jensen
1999-03-27  0:00               ` robert_dewar
1999-03-27  0:00                 ` Tarjei Tj�stheim Jensen
1999-03-25  0:00     ` Calculating SQRT in ADA robert_dewar
1999-03-24  0:00       ` Howard W. LUDWIG
1999-03-25  0:00         ` Larry Kilgallen
1999-03-24  0:00 ` bob
1999-03-24  0:00   ` Niklas Holsti
1999-03-26  0:00     ` als0045
1999-03-26  0:00       ` als0045
1999-03-26  0:00     ` bob
1999-03-26  0:00 ` Marin David Condic
1999-03-26  0:00   ` David C. Hoos, Sr.
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