Class: Markov::TransitionMatrix

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(transitions = {}, depth:) ⇒ TransitionMatrix

Returns a new instance of TransitionMatrix.



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

def initialize(transitions={}, depth:)
  @depth = depth
  @transitions = transitions
end

Instance Attribute Details

#depth ⇒ Object (readonly)

Returns the value of attribute depth.



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# File 'lib/markov/transition_matrix.rb', line 3

def depth
  @depth
end

#transitions ⇒ Object (readonly)

Returns the value of attribute transitions.



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# File 'lib/markov/transition_matrix.rb', line 3

def transitions
  @transitions
end

Instance Method Details

#add_transition(states) ⇒ Object 



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# File 'lib/markov/transition_matrix.rb', line 10

def add_transition(states)
  # p [ :add_transition, states: states, depth: depth ]
  if states.is_a?(Array) && states.count > @depth
    states = states[-(@depth)..-1]
  end

  unless states.count == depth
    raise "This transition matrix is depth #@depth, not #{states.count}!"
  end

  *key, last = states
  key.inject(@transitions) { |h,k| h[k] ||= {}; h[k] }
  key.inject(@transitions, :fetch)[last] ||= 0
  key.inject(@transitions, :fetch)[last] += 1
end

#transitions_from(states) ⇒ Object 



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# File 'lib/markov/transition_matrix.rb', line 26

def transitions_from(states)
  states = [states] unless states.is_a?(Array)

  if states.count >= @depth
    states = states[-(@depth-1)..-1]
  end

  if @depth == 1
    states = []
  end

  if states.count > 0
    @transitions.dig(*states)
  else
    @transitions
  end
end