# File lib/graphviz/theory.rb, line 12
    def adjancy_matrix
      matrix = GraphViz::Math::Matrix.new( @graph.node_count, @graph.node_count )
      
      @graph.each_edge { |e|
        x = @graph.get_node(e.node_one( false )).index
        y = @graph.get_node(e.node_two( false )).index
        matrix[x+1, y+1] = 1
        matrix[y+1, x+1] = 1 if @graph.type == "graph"
      }
      
      return matrix
    end