code: def cos_c(self, N=None):  # percent=0.9,
  		
  
  		if not hasattr(self, 'G') or self.G.shape[1] < self.rank:
  			self.fs_c(N=self.rank)  # generate
  		self.dc = norm(self.G, axis=1)**2
  		# cheaper than diag(self.G.dot(self.G.T))?
  
  		return apply_along_axis(lambda _: _/self.dc, 0, self.G[:, :N]**2)
docs: Return the squared cosines for each column.