# File lib/backports/1.9.2/stdlib/matrix.rb, line 1695
  def +(v)
    case v
    when Vector
      Vector.Raise ErrDimensionMismatch if size != v.size
      els = collect2(v) {|v1, v2|
        v1 + v2
      }
      self.class.elements(els, false)
    when Matrix
      Matrix.column_vector(self) + v
    else
      apply_through_coercion(v, __method__)
    end
  end