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
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|
