Re: Accuracy and Precision
- To: mathgroup at smc.vnet.net
- Subject: [mg36903] Re: Accuracy and Precision
- From: pkosta2002 at yahoo.com (Peter Kosta)
- Date: Tue, 1 Oct 2002 04:45:51 -0400 (EDT)
- References: <an8stl$6tq$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Thanks to all who adviced me on the correct use of
SetAccuracy. However, I still don't understand why
the order in which we set the accuracies for f, a,
and b matters.
In[1]:=
f = SetAccuracy[333.75*b^6 + a^2*(11*a^2*b^2 - b^6 -
121*b^4 - 2) + 5.5*b^8 + a/(2*b), Infinity];
a = SetAccuracy[77617., Infinity];
b = SetAccuracy[33096., Infinity];
In[4]:=
f
Out[4]=
-(54767/66192)
In[5]:=
f = SetAccuracy[333.75*b^6 + a^2*(11*a^2*b^2 - b^6 -
121*b^4 - 2) + 5.5*b^8 + a/(2*b), Infinity]
Out[5]=
1180591620717411303424
Similarily:
In[1]:=
f = SetAccuracy[333.75*b^6 + a^2*(11*a^2*b^2 - b^6 -
121*b^4 - 2) + 5.5*b^8 + a/(2*b), 50];
a = SetAccuracy[77617., 100];
b = SetAccuracy[33096., 100];
In[4]:=
f
Out[4]=
-0.8273960599468212641107299556`11.4133
In[5]:=
f = SetAccuracy[333.75*b^6 + a^2*(11*a^2*b^2 - b^6 -
121*b^4 - 2) + 5.5*b^8 + a/(2*b), 100];
Out[5]=
1.180591620717411303424`121.0721*^21
-PK