code: def vectorsToMatrix(aa, bb):
      
      MM = np.zeros([3, 3], np.float)
      for ii in range(3):
          for jj in range(3):
              MM[ii, jj] = aa[ii] * bb[jj]
      return MM
docs: Performs the vector multiplication of the elements of two vectors, constructing the 3x3 matrix.
      :param aa: One vector of size 3
      :param bb: Another vector of size 3
      :return: A 3x3 matrix M composed of the products of the elements of aa and bb :
       M_ij = aa_i * bb_j