Re: Problem of polyfit

[Henry F. Mollet]

[~] -bash-2.05b 501$ octave
GNU Octave, version 2.1.71 (powerpc-apple-darwin8.1.0).
This time around I was starting out with format long instead of default
format. I did not know that this was required to get higher precision. I
thought that my calculations using default format would be equally precise
but just not show as many digits on the screen.
Thanks, Henry
octave:1> format long
octave:22> (yhat-yf)'
octave:22> (yhat-yf)'
ans =

 Columns 1 through 3:

   3.10862446895044e-15   5.32907051820075e-15   7.10542735760100e-15

 Columns 4 through 6:

   7.10542735760100e-15   5.32907051820075e-15   5.32907051820075e-15

 Columns 7 through 9:

   5.32907051820075e-15   7.10542735760100e-15   3.55271367880050e-15

 Column 10:

   7.10542735760100e-15


  
 on 10/6/05 5:45 PM, Miroslaw Kwasniak at address@hidden wrote:

> On Thu, Oct 06, 2005 at 12:53:56PM -0700, Henry F. Mollet wrote:
>> octave:36> (yhat-yf)'
>> ans =
>> 
>>  Columns 1 through 5:
>> 
>>    -3.6364e-05   -3.9394e-05   -4.2424e-05   -4.5455e-05   -4.8485e-05
>> 
>>  Columns 6 through 10:
>> 
>>     4.8485e-05    4.5455e-05    4.2424e-05    3.9394e-05    3.6364e-05
> 
> Hmm, you have single precision aritmetic?
> 
> OCTAVE_VERSION = 2.1.50
>    -3.1086e-15    0.0000e+00    0.0000e+00    0.0000e+00    0.0000e+00
>     0.0000e+00    0.0000e+00    0.0000e+00    0.0000e+00    0.0000e+00
> 
> OCTAVE_VERSION = 2.9.2
>    -8.8818e-16   -4.4409e-15   -7.1054e-15   -3.5527e-15   -1.7764e-15
>    -3.5527e-15   -5.3291e-15   -3.5527e-15    0.0000e+00    3.5527e-15
> 
> 
> 
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Octave is freely available under the terms of the GNU GPL.

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