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"'

[download]

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

In reply to machine accuracy by maksl

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.