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Re: Why?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg110007] Re: Why?
  • From: dh <dh at metrohm.com>
  • Date: Fri, 28 May 2010 07:23:09 -0400 (EDT)
  • References: <htliht$arp$1@smc.vnet.net>

Hi Alexey,
as you get an aswer not with 60 but only 1 digit, I assume that the 
input is somehow converted into lower precision. This is in agreement with:
N[1000000000000000000000001/10^24 - 1, 60]
what gives the correct result:
1.00000000000000000000000000000000000000000000000000000000000*10^-24
Also, if you eliminate the terminal "1", you get 0.*10^-23
Or if you replace the terminal 1 by a zero, you get 0.*10^-24
Therefore, I conlude that 1.000000000000000000000001 is read as "1", 
neglecting the terminal one. This is corroborated by:
N[1.000000000000000000000001, 60]
this gives: 1.00000000000000000000000
Why this happens, I can not tell, but it looks like a bug to me.
Cheers, Daniel

Am 27.05.2010 12:46, schrieb Alexey:
> Hello,
> Consider the following:
>
> In[1]:= N[1.000000000000000000000001 - 1, 60]
>
> Out[1]= 0.*10^-24
>
> I can not understand why this happens. Can anyone explain the reason?
> What is about "arbitrary precision arithmetics"?
>


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Daniel Huber
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E-Mail:<mailto:dh at metrohm.com>
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