== MS_brow_chev_norms


  Calculate the percentages of the original matrix norm represented by the
  individual decompositions of an elasticity tensor. 

  See Browaeys and Chevrot (GJI, v159, 667-678, 2004), and function
     CIJ_brow_chev_decomp()

  [P] = CIJ_brow_chev_norms(C,Ciso)
     Isotropic part (scalar)

  [P] = CIJ_brow_chev_norms(C,Ciso,Chex)
     Isotropic, and hexagonal parts of the elastic tensor (vector)

  [P] = CIJ_brow_chev_norms(C,Ciso,Chex,Ctet,Cort,Cmon,Ctri)
     All parts of the elastic tensor (vector)
   
