Algorithm::Huffman Algorithm::Huffman is a Perl extension that implements the Huffman algorithm.
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Algorithm::Huffman Tags

Perl module algorithm Perl implementation Huffman algorithm Huffman

Algorithm::Huffman Description

Algorithm::Huffman is a Perl extension that implements the Huffman algorithm. Algorithm::Huffman is a Perl extension that implements the Huffman algorithm.SYNOPSIS use Algorithm::Huffman; my %char_counting = map {$_ => int rand(100)} ('a' .. 'z', 'A' .. 'Z'); # or better the real counting for your characters # as the huffman algorithm doesn't work good with random data :-)) my $huff = Algorithm::Huffman->new(%char_counting); my $encode_hash = $huff->encode_hash; my $decode_hash = $huff->decode_hash; my $encode_of_hello = $huff->encode_bitstring("Hello"); print "Look at the encoding bitstring of 'Hello': $encode_of_hellon"; print "The decoding of $encode_of_hello is '", $huff->decode_bitstring($encode_of_hello), "'";This modules implements the huffman algorithm. The aim is to create a good coding scheme for a given list of different characters (or even strings) and their occurence numbers.ALGORITHMPlease have a look to a good data compression book for a detailed view. However, the algorithm is like every good algorithm very easy.Assume we have a heap (keys are the characters/strings; values are their occurencies). In each step of the algorithm, the two rarest characters are looked at. Both get a suffix (one "0", the other "1"). They are joined together and will occur from that time as one "element" in the heap with their summed occurencies. The joining creates a tree growing on while the heap is reducing.Let's take an example. Given are the characters and occurencies. a (15) b(7) c(6) d(6) e(5)In the first step e and d are the rarest characters, so we create this new heap and tree structure: a(15) de(11) b(7) c(6) de / "0"/ "1" d eNext Step: a(15) bc(13) de(11) de bc / / "0"/ "1" "0"/ "1" d e b cNext Step: a(15) bcde(24) bcde / "0"/ "1" / de bc / / "0"/ "1" "0"/ "1" d e b cNext Step unifies the rest: Huffman-Table / "0"/ "1" / / bcde a / "0"/ "1" / de bc / / "0"/ "1" "0"/ "1" d e b cFinally this encoding table would be created: a 1 b 010 c 011 d 000 e 001Please note, that there is no rule defining what element in the tree is ordered to left or to right. So it's also possible to get e.g. the coding scheme: a 0 b 100 c 101 d 110 e 111 Requirements: · Perl

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