text: """
    Name     : c9_32_matrix_multiplication.py
    Book     : Python for Finance (2nd ed.)
    Publisher: Packt Publishing Ltd. 
    Author   : Yuxing Yan
    Date     : 6/6/2017
    email    : yany@canisius.edu
               paulyxy@hotmail.com
  """
  
  import numpy as np
  ret=np.matrix(np.array([[0.1,0.2],[0.10,0.1071],[-0.02,0.25],[0.012,0.028],[0.06,0.262],[0.14,0.115]]))
  covar=np.dot(ret.T,ret)
  print("covar")
  print(covar)
  