`initialize_copy': undefined method `init_rows'

[Bortechino]

extendmatrix-0.4/lib/extendmatrix.rb:309:in initialize_copy': undefined method init_rows' for #Matrix:0x00005580c849f680 (NoMethodError)

def initialize_copy(orig)
    init_rows(orig.rows, true)
    self.wrap=(orig.wrap)
  end

Besides, unnecessary require 'rational'