module CsrMatrix
	module Decompositions
		include Contracts::Core
    C = Contracts

    Contract C::None => C::ArrayOf[C::ArrayOf[C::Num]]
		def eigen()
			# alias for eigensystem
			# returns a list in the form {eigenvalues, eigenvectors}
			is_invariant?
			
  		self.eigenvalue()
		end # eigen
      
    Contract C::None => C::ArrayOf[C::ArrayOf[C::Num]]
		def eigenvalue()
			# identifies the eigenvalues of a matrix
			is_invariant?
			# post 	eigenvalues of the matrix
			m = Matrix.rows(self.decompose)
			return m.eigensystem().to_a[1].round().to_a
		end # eigenvalue
  end # Decompositions
end # CsrMatrix