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Re: Next representable number

• To: mathgroup at smc.vnet.net
• Subject: [mg73589] Re: Next representable number
• From: Bill Rowe <readnewsciv at sbcglobal.net>
• Date: Thu, 22 Feb 2007 04:40:09 -0500 (EST)

On 2/21/07 at 1:53 AM, andrew.j.moylan at gmail.com (Andrew Moylan)
wrote:

>What's a neat way to determine the next (higher) representable
>number (at a given precision)? That is, I want f[x] to be the
>smallest representable number (at precision Precision[x]) that's
>larger than x.

Take a look at the functions in the package NumericalMath`Microscope`

=46or example

In[1]:=
<<NumericalMath`

In[2]:=
Ulp[2.]

Out[2]=
2.220446049250313*^-16

indicating the nearest machine numbers to 2 on my machine are
2.2E-16 away from 2. Note, these results are platform dependent.
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