Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
If you're just looking for an estimate, why not work on a manageable and reasonably sampled subset of the data?

Because, according to (my application of) the formulae I found on line, I should be seeing false positive after low 10s of millions of inserts. But my testing showed none after 1e6, 10e6, 100e6, 200e6 ...

Ie. My sampling showed that the calculations were wrong, but provided no information upon which to draw any further conclusions.

The nature of the beast is that I needed to run the experiment for 3/4 of a billion iterations in order to get my first piece of actual information from it.

This start out being about verify my gut with respect to the big strings. That lead to looking for a mechanism capable of verifying uniqueness with the huge numbers involved. That lead -- through various documented mechanisms that proved inadequate -- to coming up with the current schema that appears to work substantially better than all the documented mechanisms.

This post is about trying to come up with math that fits the experimental evidence.


With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?


In reply to Re^2: [OT] The statistics of hashing. by BrowserUk
in thread [OT] The statistics of hashing. by BrowserUk

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 musing on the Monastery: (7)
    As of 2018-08-20 02:42 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?
      Asked to put a square peg in a round hole, I would:









      Results (190 votes). Check out past polls.

      Notices?