Re: How to print this function?

[marco atzeri]

On 5/22/2012 10:50 PM, Max Brister wrote:
> Actually, [-100000:1:100000;] is fine. Look at the code here
> http://hg.savannah.gnu.org/hgweb/octave/file/d95e719ef108/liboctave/Range.cc#l59
>
> Octave's algorithm for getting a matrix from a range works as folows
> 1) Determine the number of elements in a range
> 2) Compute each index of the matrix using the equation: result(i) =
> base + i * increment; where i is integer and goes from 0 to the number
> of elements.
>
> So there will be some difference between [-1:0.00001:1;]-0.00001 and
> [-100000:1:100000;] due to floating point roundoff errors. However,
> this difference does not accumulate. If we look at
>
> [a,b] = max(abs([-1:0.00001:1;]-0.00001*[-100000:1:100000;]))
>
> We see that the greatest error occurs at the 150001 element out of
> 200001 elements total. If the error was accumulating, we would expect
> for the largest difference to occur closer to the end. Furthermore, if
> there was actually an accuracy issue we would expect to see a
> different number of columns in each matrix.

very interesting Max,

in reality half of the values are equal around eps/2 and the rest
are smaller than that

  a = abs([-1:0.00001:1;]-0.00001*[-100000:1:100000;]);
  hist(a)


Regards
Marco