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