From: Dennis Lee Bieber <wlfraed@ix.netcom.com>
Subject: Re: Ada.Numerics, Accuracy of trigonometric functions
Date: Fri, 07 Oct 2016 10:52:49 -0400
Date: 2016-10-07T10:52:49-04:00 [thread overview]
Message-ID: <g8dfvb5eln7isqv9k9ihjp0ts5b28o1vhn@4ax.com> (raw)
In-Reply-To: nt7sgs$1a06$1@gioia.aioe.org
On Fri, 7 Oct 2016 12:13:48 +0200, Markus Schöpflin <no.spam@spam.spam>
declaimed the following:
>X = 4294967296.00000; COS(X) = 1.00000 <-- WHAT?
That kind of surprises me... Not the cos() result, but the input X
Short float should only have around 23-24 bits of significance in the
mantissa -- enough for around 7 decimal digits. Yet you are seeing the full
UNSIGNED 32-bit integer value with a stack of fractional zeros tacked on.
I'm tempted to think the compiler, not the run-time, is computing the
2^32 as a universal (or whatever the preferred term is) constant using the
smallest data type that holds the full value.
--
Wulfraed Dennis Lee Bieber AF6VN
wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/
next prev parent reply other threads:[~2016-10-07 14:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 10:13 Ada.Numerics, Accuracy of trigonometric functions Markus Schöpflin
2016-10-07 10:23 ` Markus Schöpflin
2016-10-07 10:23 ` Brian Drummond
2016-10-07 10:40 ` Markus Schöpflin
2016-10-07 14:52 ` Dennis Lee Bieber [this message]
2016-10-07 15:19 ` Markus Schöpflin
2016-10-07 22:15 ` Dennis Lee Bieber
2016-10-07 16:38 ` Jeffrey R. Carter
2016-10-10 7:44 ` Markus Schöpflin
2016-10-22 22:38 ` Robert Eachus
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