Class: RandomData::MarkovGenerator

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

Instance Method Summary collapse

Constructor Details

#initialize(memory = 1) ⇒ MarkovGenerator

Returns a new instance of MarkovGenerator.



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# File 'lib/random_data/markov.rb', line 7

def initialize(memory = 1)
  @memory_size = memory
  @table = Hash.new {|h,k| h[k] = {}}
  @state = []
end

Instance Method Details

#generate(n = 1, clear_state = false) ⇒ Object 



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# File 'lib/random_data/markov.rb', line 34

def generate(n=1, clear_state=false)
  @state = [] if clear_state
  results = []
  n.times do
    retry_count = 0
    begin
      result_hash = @table[Marshal.dump(@state)]
      the_keys,the_vals = [],[]
      result_hash.each_pair do |k,v|
        the_keys << k
        the_vals << v
      end
      # get the weighted random value, by index.
      i = the_vals.roulette
    rescue
      # puts "results:#{result_hash.inspect}";
      # puts "keys:#{the_keys.inspect}";
      # puts "vals:#{the_vals.inspect}";
      # puts "state:#{@state.inspect}";
      @state = []
      retry_count += 1
      if retry_count < 5
        retry 
      else
        # puts
        # puts "table:#{@table.inspect}";
        raise
      end
    end
    result = the_keys[i]
    # puts "index:#{i.inspect}";

    next_state(result)
    if block_given?
      yield result
    end
    results << result
  end
  return results
end

#insert(result) ⇒ Object

given the next token of input add it to the table



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

def insert(result)
  # puts "insert called with #{result}"
  tabindex = Marshal.dump(@state)
  if @table[tabindex].has_key?(result)
    @table[tabindex][result] += 1
  else
    @table[tabindex][result] = 1
  end
  # puts "table #{@table.inspect}"
  next_state(result)
end

#next_state(result) ⇒ Object 



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# File 'lib/random_data/markov.rb', line 28

def next_state(result)
  @state.shift if @state.size >= @memory_size
  @state.push(result)
  # puts "@state is #{@state.inspect}"
end