machine accuracy

[maksl]

dear monks;

i have to deal with numeric limits in perl. not exactly of the size npiazza deals with, but i need to know my machine accuracy. it's knowledge is crucial in order to eventually trust the computed data. :)

i've come up with this rapid one-liner:

perl -e '$eps=1;while(1<1+$eps){$eps/=2;}print "$eps\n"'

please tell me if my assumption are nuts. on a debian x86 and alpha i get: 1.11022302462516e-16
number that is found on various googled site in relation with the "NAG Fortran Library" and its precesion (example).

e~(N)^(1/2)*eps
where eps would be the machine accuracy.
N the number of multiplications.
e would result in the supposed mean fault

thx for your advice maksl