Class: Lernen::Equiv::RandomWordOracle

Inherits:
Oracle
  • Object
show all
Defined in:
lib/lernen/equiv/random_word_oracle.rb

Overview

RandomWordOracle provides an implementation of equivalence query that finds a counterexample by using random word generation.

This takes three important parameters:

  • max_words (default: 100): It is a limit of number of random words. If random words is generated and tried up to this value and no counterexample is found, it returns nil finally.
  • min_word_size (default: 1): It is the minimal size of randomly generated word. It should be greater than 0.
  • max_word_size (default: 30): It is the maximal size of randomly generated word. It should be greater than or equal to min_word_size.

Instance Attribute Summary

Attributes inherited from Oracle

#sul

Instance Method Summary collapse

Methods inherited from Oracle

#+, #stats

Constructor Details

#initialize(alphabet, sul, max_words: 100, min_word_size: 1, max_word_size: 30, random: Random) ⇒ RandomWordOracle

: ( Array alphabet, System::SUL[In, Out] sul, ?max_words: Integer, ?min_word_size: Integer, ?max_word_size: Integer, ?random: Random, ) -> void



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# File 'lib/lernen/equiv/random_word_oracle.rb', line 36

def initialize(alphabet, sul, max_words: 100, min_word_size: 1, max_word_size: 30, random: Random)
  super(sul)

  @alphabet = alphabet
  @max_words = max_words
  @min_word_size = min_word_size
  @max_word_size = max_word_size
  @random = random
end

Instance Method Details

#find_cex(hypothesis) ⇒ Object 



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# File 'lib/lernen/equiv/random_word_oracle.rb', line 47

def find_cex(hypothesis)
  super

  @max_words.times do
    reset_internal(hypothesis)
    word = []

    word_size = @random.rand(@min_word_size..@max_word_size)
    word_size.times do
      word << @alphabet.sample(random: @random)

      hypothesis_output, sul_output = step_internal(hypothesis, word.last)

      if hypothesis_output != sul_output # steep:ignore
        @sul.shutdown
        return word
      end
    end
  end

  nil
end