Beefy Boxes and Bandwidth Generously Provided by pair Networks
Just another Perl shrine
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Hi everyone, I'm rather new to perl, and have been trying to impelement a calculation of hypergeometric distribution probabilities into some code. For those of you that aren't familiar, these statistics address the following type of question:

"If I have a box with 300 white balls and 700 black balls and I draw 100 balls from the box, what are the odds that I draw 40 or more white balls".

I've encountered two (related) problems:

1 These calculations require very large numbers, apparently necessitating the use of a module such as BigInt or BigFloat (though I don't fully understand at what size number these modules become necessary). By playing with someone else's publicly available code and clumsily implementing this functionality, I was able to get things to work... however:

2 Especially when I'm using very large samples, the process of calculating the probability of is excruciatingly slow due to the large number of factorial calculations necessary.

I would greatly appreciate advice on which "big number" module is the most efficient for factorials, and whether there is any conventional wisdom as to how I could best tackle this problem.

Thanks!
-ollie-

In reply to Fastest way to calculate hypergeometric distribution probabilities (i.e. BIG factorials)? by Commander Salamander

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, 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 romping around the Monastery: (6)
    As of 2020-01-26 21:02 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?
      Notices?