Hi, When anomalous data is available, both F+ and F- will be assumed to be independent variables (unless you merge them as Pavel described). I did refine f' and f" for a nice high reso twinned data set once and the results were quite encouraging. I am not sure how reliable this would be for more challenging data. HTH Peter 2008/10/20, Pavel Afonine :

Hi Francis,

by default both F+ and F- are used in phenix.refine. However, you can request that the average values, Fobs_ave = (F+ + F-)/2 are used instead ("xray_data.force_anomalous_flag_to_be_equal_to=False" keyword).

Peter may have more details on how this is handled in twin-refinement.

Pavel.

On 10/20/2008 7:45 AM, Francis E Reyes wrote: All

How does phenix.refine handle the twin refinement target when refining against F+/F-? I'm specifically asking for the proper assignment of F+/F- for twin related reflections (e.g. 10.1107/S0907444902021704). My data is currently in P41 with friedel pairs as output by scala.

Thanks

FR

--------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder

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