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    Algorithm::Bucketizer 0.13
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NAME
    Algorithm::Bucketizer - Distribute sized items to buckets with limited
    size

SYNOPSIS
      use Algorithm::Bucketizer;

          # Create a bucketizer
      my $bucketizer = Algorithm::Bucketizer->new(bucketsize => $size);

          # Add items to it
      $bucketizer->add_item($item, $size);

          # Optimize distribution
      $bucketizer->optimize(maxrounds => 100);

          # When done adding, get the buckets
          # (they're of type Algorithm::Bucketizer::Bucket)
      my @buckets = $bucketizer->buckets();

          # Access bucket content by using
          # Algorithm::Bucketizer::Bucket methods
      my @items  = $bucket->items();
      my $serial = $bucket->serial();

DESCRIPTION
    So, you own a number of mp3-Songs on your hard disc and want to copy
    them to a number of CDs, maxing out the space available on each of them?
    You want to distribute your picture collection into several folders, so
    each of them doesn't exceed a certain size? "Algorithm::Bucketizer"
    comes to the rescue.

    "Algorithm::Bucketizer" distributes items of a defined size into a
    number of dynamically created buckets, each of them capable of holding
    items of a defined total size.

    By calling the "$bucketizer->add_item()" method with the item (can be a
    scalar or an object reference) and its size as parameters, you're adding
    items to the system. The bucketizer will determine if the item fits into
    one of the existing buckets and put it in there if possible. If none of
    the existing buckets has enough space left to hold the new item (or if
    no buckets exist yet for that matter), the bucketizer will create a new
    bucket and put the item in there.

    After adding all items to the system, the bucketizer lets you iterate
    over all buckets with the "$bucketizer->items()" method and determine
    what's in each of them.

  Algorithms
    Currently, "Algorithm::Bucketizer" comes with two algorithms, "simple"
    and "retry".

    In "simple" mode, the algorithm will just try to fit in your items in
    the order in which they're arriving. If an item fits into the current
    bucket, it's being dropped in, if not, the algorithm moves on to the
    next bucket. It never goes back to previous buckets, although a new item
    might as well fit in there. This mode might be useful if preserving the
    original order of items is required. To query/manipulate the bucket the
    Bucketizer will try to fit in the next item, use
    "current_bucket_index()" explained below.

    In "retry" mode, the algorithm will try each existing bucket first,
    before opening a new one. If you have many items of various sizes,
    "retry" allows you to fit them into less buckets than in "simple" mode.

    The "new()" method chooses the algorithm:

        my $dumb = Algorithm::Bucketizer->new( algorithm => "simple" );

        my $smart = Algorithm::Bucketizer->new( algorithm => "retry" );

    In addition to these inserting algorithms, check "Optimize" to optimize
    the distribution, minimizing the number of required buckets.

  Prefilling Buckets
    Sometimes you will have preexisting buckets, which you need to tell the
    algorithm about before it starts adding new items. The
    "prefill_bucket()" method does exactly that, simply putting an item into
    a specified bucket:

        $b->prefill_bucket($bucket_idx, $item, $itemsize);

    $bucket_idx is the index of the bucket, starting from 0. Non-existing
    buckets are automatically created for you. Make sure you have a
    consecutive number of buckets at the end of the prefill.

  Optimize
    Once you've inserted all items, you might choose to optimize the
    distribution over the buckets, in order to *minimize* the number of
    required buckets to hold all the elements.

    Optimally distributing a number discrete-sized items into a number of
    discrete-sized buckets, however, is a non-trivial task. It's the
    "bin-packing problem", related to the "knapsack problem", which are both
    *NP-complete*.

    "Algorithm::Bucketize" therefore provides different optimization
    techniques to (stupidly) approximate an ideal solution, which can't be
    obtained otherwise (yet).

    Currently, it implements "random" and "brute_force".

    "random" tries to randomly vary the distribution until a time or round
    limit is reached.

            # Try randomly to improve distribution, 
            # timing out after 100 rounds
        $b->optimize(algorithm => "random", maxrounds => 100);

            # Try randomly to improve distribution, 
            # timing out after 60 secs
        $b->optimize(algorithm => "random", maxtime => 60);

            # Try to improve distribution by brute_force trying
            # all possible combinations (watch out: can take forever)
        $b->optimize(algorithm => "brute_force",
                     maxtime => ..., 
                     maxrounds => ...,