Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

It's an interesting concept. If I understand (and please correct me if I'm wrong), you're using the unpredictability of the relationship between a few asynchronous threads as an entropy source, and then reducing that entropy to, in this case, a range of 0 .. 23, though it could just as easily be full bytes, or something else.

When I run it with threaded Perl 5.14.2 on Ubuntu 13.04 (the only threaded Perl I have built at the moment), my distributions are not nearly so nice as yours. I keep seeing things like:

{ "0" => 3810, "2" => 5960, "16" => 230 }

I have no idea why there's a difference. I fiddled with different numbers of threads, but that didn't produce appreciable improvements toward getting a smoother distribution.

I also wonder if you need to consider modulo bias. Well, actually looking at the code again, I don't wonder, I'm pretty sure modulo bias can be an issue if $M is set to a number that doesn't divide evenly into 2^32.

Initially I intended to test your code with A Perl adaptation of the FIPS-140-2 test, and A randomness dispersion test, but it doesn't take that sharp of an instrument to spot clusters when there are only three numbers drawn out of a possible 24 given thousands of picks.

Any thoughts why this works for you and not for me?


Dave


In reply to Re^3: generate random number without using any built in function in perl? by davido
in thread generate random number without using any built in function in perl? by anurag_perl

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!
  • 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, 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, 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.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others perusing the Monastery: (5)
    As of 2015-07-04 23:37 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (60 votes), past polls