Re: Why?
- To: mathgroup at smc.vnet.net
- Subject: [mg110010] Re: Why?
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Fri, 28 May 2010 07:23:42 -0400 (EDT)
On 5/27/10 at 6:46 AM, lehin.p at gmail.com (Alexey) wrote: >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"? The problem is you are attempting to convert a number from one precision to a higher precision. That is: In[9]:= Precision[1.000000000000000000000001] Out[9]= 24. But if you had entered the real value as having 60 digit precision things would work as you expect. That is: In[10]:= 1.000000000000000000000001`60 - 1 Out[10]= 1.00000000000000000000000000000000000*10^-24 or you could have started with exact values and used N to convert then to 60 digit precision, i.e., In[11]:= N[1 + 10^-24, 60] - 1 Out[11]= 1.00000000000000000000000000000000000*10^-24