Hi all

I'm trying to get some measure of the amount of texture when using spherical harmonics.

As per here, I've entered

    PO_Spherical_Harmonics(sh, 8)
    Texture_Index(sh, 0)

into my input file, but the texture index is being returned as 1.

What am I doing wrong?

Also, is there a reference for this as to what it is actually doing?
.

I'm using 8th order harmonics on corundum (R-3C). The refined values are

		PO_Spherical_Harmonics(sh, 8 load sh_Cij_prm {
			y00   !sh_c00  1.00000
			y20   sh_c20   3.45732`
			y40   sh_c40   3.21439`
			y43m  sh_c43m  0.06270`
			y60   sh_c60   2.30631`
			y63m  sh_c63m -0.08453`
			y66p  sh_c66p -0.03784`
			y80   sh_c80   1.27055`
			y83m  sh_c83m  0.23360`
			y86p  sh_c86p -0.04219`
			} )

If I add what I think Texture_Index is doing, I get the following:

		prm = 1 + (1/5) (sh_c20^2) +
		           (1/9) (sh_c40^2 + sh_c43m^2) +
		           (1/13) (sh_c60^2 + sh_c63m^2 + sh_c66p^2) +
		           (1/17) (sh_c80^2 + sh_c83m^2 + sh_c86p^2); :  5.04731`