Class: Ravensat::PropLogic

Inherits:
Object
  • Object
show all
Defined in:
lib/ravensat/prop_logic.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(init_formula) ⇒ PropLogic

Returns a new instance of PropLogic.



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# File 'lib/ravensat/prop_logic.rb', line 6

def initialize( init_formula )
  @formula = init_formula
     # (a | b) & (~a | b) & (a | ~b) & (~a | ~b)

     # [:and,
     #    [:or, a, b],
     #    [:or, [:not, a], b],
     #    [:or, a, [:not, b]],
     #    [:or, [:not, a], [:not, b]]
     # ]
end

Instance Attribute Details

#formula ⇒ Object (readonly)

Returns the value of attribute formula.



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# File 'lib/ravensat/prop_logic.rb', line 3

def formula
  @formula
end

#name_table ⇒ Object (readonly)

Returns the value of attribute name_table.



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# File 'lib/ravensat/prop_logic.rb', line 4

def name_table
  @name_table
end

Instance Method Details

#&(object) ⇒ Object 



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# File 'lib/ravensat/prop_logic.rb', line 60

def &( object )
  if @formula.first == :and
    @formula.append object.formula
  else
    @formula = [:and, @formula, object.formula]
  end
  self
  # Ravensat::PropLogic.new [:and, @formula, object]
  # formulaがcnfである前提の実装
  # @formula & other_formula
end

#to_cnf ⇒ Object 



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# File 'lib/ravensat/prop_logic.rb', line 18

def to_cnf

end

#to_dimacs ⇒ Object 



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# File 'lib/ravensat/prop_logic.rb', line 22

def to_dimacs
  cnf_text = String.new
  tmp_name_table = @formula.flatten.uniq.reject{|e| e.class == Symbol}
  @name_table = tmp_name_table.zip((1..tmp_name_table.size).to_a.map{|e| e.to_s}).to_h

  nr_vars = tmp_name_table.size
  nr_clses = @formula.size - 1
  cnf_header = 'p cnf ' << nr_vars.to_s << ' ' << nr_clses.to_s << "\n"
  # @formula.is_cnf?
  @formula.each do |clause|
    # next if clause.first != :and
    case clause
    when Symbol
      next
    when Array
      case clause.first
      when :or
        clause.each do |literal|
          case literal
          when Symbol
            next
          when Ravensat::PropVar
            cnf_text << @name_table[literal] << ' '
          when Array #&& literal.first == :not
            cnf_text << '-' << @name_table[literal.last] << ' '
          end
        end
      when :not
        cnf_text << '-' << @name_table[clause.last] << ' '
      end
    when Ravensat::PropVar
      cnf_text << @name_table[clause] << ' '
    end
    cnf_text << '0' << "\n"
  end
  cnf_header + cnf_text
end

#|(object) ⇒ Object 



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# File 'lib/ravensat/prop_logic.rb', line 72

def |( object )
  if @formula.first == :or
    @formula.append object.formula
  else
    @formula = [:or, @formula, object.formula]
  end
  self
  # Ravensat::PropLogic.new [:or, @formula, object]
  # 木構造に落とすのが難しそう，実装見送り
  # @formula | other_formula
end