NAME
    DateTime::Event::Predict - Predict new dates from a set of dates

SYNOPSIS
    Given a set of dates this module will predict the next date or dates to
    follow.

      use DateTime::Event::Predict;

      my $dtp = DateTime::Event::Predict->new(
          profile => {
              buckets => ['day_of_week'],
          },
      );

      # Add today's date: 2009-12-17
      my $date = new DateTime->today();
      $dtp->add_date($date);

      # Add the previous 14 days
      for  (1 .. 14) {
          my $new_date = $date->clone->add(
              days => ($_ * -1),
          );

          $dtp->add_date($new_date);
      }

      # Predict the next date
      my $predicted_date = $dtp->predict;

      print $predicted_date->ymd;

      # 2009-12-18

    Here we create a new "DateTime" object with today's date (it being
    December 17th, 2009 currently). We then use add_date to add it onto the
    list of dates that "DateTime::Event::Predict" (DTP) will use to make the
    prediction.

    Then we take the 14 previous days (December 16-2) and them on to same
    list one by one. This gives us a good set to make a prediction out of.

    Finally we call predict which returns a "DateTime" object representing
    the date that DTP has calculated will come next.

HOW IT WORKS
    Predicting the future is not easy, as anyone except, perhaps,
    Nostradamus will tell you. Events can occur with perplexing randomness
    and discerning any pattern in the noise is nigh unpossible.

    However, if you have a set of data to work with that you know for
    certain contains some sort of regularity, and you have enough
    information to discover that regularity, then making predictions from
    that set can be possible. The main issue with our example above is the
    tuning we did with this sort of information.

    When you configure your instance of DTP, you will have to tell what
    sorts of date-parts to keep track of so that it has a good way of making
    a prediction. Date-parts can be things like "day of the week", "day of
    the year", "is a weekend day", "week on month", "month of year",
    differences between dates counted by "week", or "month", etc. Dtpredict
    will collect these identifiers from all the provided dates into
    "buckets" for processing later on.

EXAMPLES
    Predicting Easter
    Predicting

METHODS
  new
    Constructor

            my $dtp = DateTime::Event::Predict->new();

  dates
    Arguments: none | \@dates

    Return value: \@dates

    Called with no argument this method will return an arrayref to the list
    of the dates currently in the instance.

    Called with an arrayref to a list of DateTime objects ("\@dates") this
    method will set the dates for this instance to "\@dates".

  add_date
    Arguments: $date

    Return value:

    Adds a date on to the list of dates in the instance, where $date is a
    DateTime object.

  profile
    Arguments: $profile

    Set the profile for which date-parts will be

      # Pass in preset profile by name
      $dtp->profile( profile => 'default' );
      $dtp->profile( profile => 'holiday' );

      # Create a new profile
      my $profile = new DateTime::Event::Predict::Profile(
          buckets => [qw/ minute hour day_of_week day_of_month /],
      );

      $dtp->profile( profile => $profile );

   Provided profiles
    The following profiles are provided for use by-name:

  predict
    Arguments: %options

    Return Value: $next_date | @next_dates

    Predict the next date(s) from the dates supplied.

      my $predicted_date = $dtp->predict();

    If list context "predict" returns a list of all the predictions, sorted
    by their probability:

      my @predicted_dates = $dtp->predict();

    The number of prediction can be limited with the "max_predictions"
    option.

    Possible options

      $dtp->predict(
          max_predictions => 4, # Once 4 predictions are found, return back
          callbacks => [
              sub { return ($_->second % 4) ? 0 : 1 } # Only predict dates with second values that are divisible by four.
          ],
      );

    max_predictions
        Maximum number of predictions to find.

    callbacks
        Arrayref of subroutine callbacks. If any of them return a false
        value the date will not be returned as a prediction.

  train
    Train this instance of DTP

TODO
    *   It would be be cool if you could pass your own buckets in with a
        certain type, so you could, say, look for recurrence based on
        intervals of 6 seconds, or 18 days, whatever.

    *   We need to be able to handle recording more than one interval per
        diff. If the dates are all offset from each other by 1 day 6 hours
        (May 1, 3:00; May 2, 6:00), we can't be predicting a new date that's
        exactly 1 day after the most recent one. ^ The best way to do this
        is probably to record intervals as epoch seconds, so everything is
        taken into account. Maybe record epoch seconds in addition to whole
        regular intervals like days & hours.

AUTHOR
    Brian Hann, "<brian.hann at gmail.com>"

BUGS
    Please report any bugs or feature requests to
    "bug-datetime-event-predict at rt.cpan.org", or through the web
    interface at
    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=DateTime-Event-Predict>.
    I will be notified, and then you'll automatically be notified of
    progress on your bug as I make changes.

SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc DateTime::Event::Predict

    You can also look for information at:

    *   RT: CPAN's request tracker

        <http://rt.cpan.org/NoAuth/Bugs.html?Dist=DateTime-Event-Predict>

    *   AnnoCPAN: Annotated CPAN documentation

        <http://annocpan.org/dist/DateTime-Event-Predict>

    *   CPAN Ratings

        <http://cpanratings.perl.org/d/DateTime-Event-Predict>

    *   Search CPAN

        <http://search.cpan.org/dist/DateTime-Event-Predict/>

COPYRIGHT & LICENSE
    Copyright 2009 Brian Hann, all rights reserved.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

SEE ALSO
    DateTime, DateTime::Event::Predict::Profile