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What are those methods of xray.scatterer for?

And what are their relation to set_grad_u_iso and set_grad_u_aniso?

You can use any combination of u_iso and u_star (anisotropic). We had to make this generalization to accomodate TLS refinement. I.e. there are four combinations, use_u_iso/use_u_aniso false/false, true/false, false/true, true/true. The total Debye-Waller factor is the product dw_iso * dw_aniso. If use_u_iso is false, dw_iso = 1, similarly dw_aniso = 1 if use_u_ansio is false. Unfortunately I didn't find the time yet to eliminate the anisotropic_flag, which is redundant. The main problem is that phaser needs to be changed in many places in order to get rid of the flag. The grad_u_iso and grad_u_ansio control the computation of the gradients. The flags are independent of corresponding use flags. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com