# File narray_ext.rb, line 171
  def rmsdev(*ranks)
    if integer?
      a = self.to_type(NArray::DFLOAT)
    else
      a = self
    end
    a = NArray.ref(a)
    n = rank_total(*ranks)
    if complex?
      NMath::sqrt( (( a-a.accum(*ranks).div!(n) ).abs**2).sum(*ranks)/n )
    else
      NMath::sqrt( (( a-a.accum(*ranks).div!(n) )**2).sum(*ranks)/n )
    end
  end