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To: python-list@python.org
From: Dennis Lee Bieber <wlfraed@ix.netcom.com>
Subject: Re: Setting longer default decimal precision
Date: Mon, 18 Nov 2013 20:29:43 -0500
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Xref: csiph.com comp.lang.python:59930

On Mon, 18 Nov 2013 14:14:33 +0000, "Kay Y. Jheallee" <nospam@use.net>
declaimed the following:

>Using 1/3 as an example,
>
> >>> 1./3
>0.3333333333333333
> >>> print "%.50f" % (1./3)
>0.33333333333333331482961625624739099293947219848633
> >>> print "%.50f" % (10./3)
>3.33333333333333348136306995002087205648422241210938
> >>> print "%.50f" % (100./3)
>33.33333333333333570180911920033395290374755859375000
>
>which seems to mean real (at least default) decimal precision

	The default double precision FLOATING POINT is limited to ~15
significant digits. That's a hardware limit for double on most machines
(64-bits). Most floating point processors may use 80 bits internally, but
truncate back down on output.

	Python has supported a DECIMAL package for some years, but math with
that package will be slower as it can't go through the FPU.

Check the help file for your installation, look for decimal


-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/