# File lib/graphviz/math/matrix.rb, line 106
      def *(m)
        matrix = GraphViz::Math::Matrix.new( @line, @line )
        
        @line.times do |line|
          @line.times do |column|
            l = self.line(line+1)
            c = m.column(column+1)
            v = 0
            l.size.times do |i|
              v += l[i]*c[i]
            end
            matrix[line+1,column+1] = v
          end
        end
        
        return matrix
      end