Class: Ebooks::MarkovModel

Inherits:
Object
  • Object
show all
Defined in:
lib/twitter_ebooks/markov.rb

Constant Summary collapse

INTERIM =

Special token marking newline/^/$ boundaries

:interim

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#depth ⇒ Object (readonly)

Returns the value of attribute depth.



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# File 'lib/twitter_ebooks/markov.rb', line 6

def depth
  @depth
end

#tokens ⇒ Object

Returns the value of attribute tokens.



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# File 'lib/twitter_ebooks/markov.rb', line 5

def tokens
  @tokens
end

Instance Method Details

#chain(tokens) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/twitter_ebooks/markov.rb', line 51

def chain(tokens)
  next_token = nil
  @depth.downto(1).each do |i|
    next if tokens.length < i
    matches = @model[tokens.last(i)]
    if matches
      #p tokens.last(i)
      #puts "=> #{matches.inspect}"
      next_token = matches.sample
      break
    end
  end

  raise ArgumentError if next_token.nil?

  if next_token == INTERIM
    return tokens
  else
    return chain(tokens + [next_token])
  end
end

#consume(tokenized, depth = 2) ⇒ Object 



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# File 'lib/twitter_ebooks/markov.rb', line 16

def consume(tokenized, depth=2)
  @tokens = [INTERIM]
  @depth = depth

  tokenized.each do |tokens|
    @tokens += tokens
    @tokens << INTERIM
  end

  @model = {}

  @tokens.each_with_index do |token, i|
    prev_tokens = []

    @depth.downto(1) do |j|
      if i-j < 0; next
      else; prev = represent(@tokens[i-j])
      end
      prev_tokens << prev
    end

    1.upto(@depth) do |j|
      break if j > prev_tokens.length
      ngram = prev_tokens.last(j)

      unless ngram == INTERIM && prev_tokens[-1] == INTERIM
        @model[ngram] ||= []
        @model[ngram] << represent(token)
      end
    end
  end

  self
end

#deserialize(data) ⇒ Object 



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# File 'lib/twitter_ebooks/markov.rb', line 83

def deserialize(data)
  @model = data['model']
  @depth = data['depth']
  self
end

#generate ⇒ Object 



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# File 'lib/twitter_ebooks/markov.rb', line 73

def generate
  tokens = chain([@model[[INTERIM]].sample])
  NLP.reconstruct(tokens)
end

#represent(token) ⇒ Object 



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# File 'lib/twitter_ebooks/markov.rb', line 8

def represent(token)
  if token.nil? || token == "\n" || token.empty?
    INTERIM
  else
    token
  end
end

#serialize ⇒ Object 



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# File 'lib/twitter_ebooks/markov.rb', line 78

def serialize
  { 'model' => @model,
    'depth' => @depth }
end