== MS_tandon_and_weng

  [CC,rh]=tandon_and_weng(vp,vs,rho,del,c,vpi,vsi,rhoi)

  Calculate anisotropic elastic constants for an isotropic material containing
  spheroidal inclusions with a symmetry axis aligned with the x1-direction.

  From the theory of Tandon and Weng (1984). 

  Input parameters:
       vp,vs,rho : isotropic parameters of the matrix (m/s, kg/m3)
             del : aspect ratio of spheroids:
                      del < 1 = smarties
                      del = 1 = spheres
                      del > 1 = cigars
               c : volume fractions of inclusions       
  vpi, vsi, rhoi : isotropic parameters of the inclusions

  Output parameters:
     CC : Elastic constants (actually Aij, density normalised)
     rh : aggregate density

  Based on FORTRAN code by Mike Kendall, translated into matlab
  by James Wookey, 2006
