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Optimisation: Difference between revisions
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→Wilson outliers (aliens)
(paragraph about beam divergence and mosaicity) |
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* Another way to judge Wilson outliers is to identify resolution ranges that deviate from 1. in the table '''HIGHER ORDER MOMENTS OF WILSON DISTRIBUTION OF ACENTRIC DATA''' in [[CORRECT.LP]]. "Aliens" that are put into REMOVE.HKL will lower the values in these resolution ranges! | * Another way to judge Wilson outliers is to identify resolution ranges that deviate from 1. in the table '''HIGHER ORDER MOMENTS OF WILSON DISTRIBUTION OF ACENTRIC DATA''' in [[CORRECT.LP]]. "Aliens" that are put into REMOVE.HKL will lower the values in these resolution ranges! | ||
* SCALEPACK users: don't confuse this process of rejecting Wilson outliers with the iterative procedure of rejecting scaling outliers that is usually done when using SCALEPACK. Scaling outliers are handled non-iteratively in [[XDS]]; the only way to influence [[XDS]] in this respect is by modifying [[WFAC1]]. | * SCALEPACK users: don't confuse this process of rejecting Wilson outliers with the iterative procedure of rejecting scaling outliers that is usually done when using SCALEPACK. Scaling outliers are handled non-iteratively in [[XDS]]; the only way to influence [[XDS]] in this respect is by modifying [[WFAC1]]. | ||
* if CORRECT rejects many "aliens" in a very weak high resolution shell because they have Z>20 then this is due to the fact that the reflections do not obey Wilson statistics. If this happens, the REJECT_ALIEN parameter should be set much higher (e.g. 100). | |||
=== Optimizing the anomalous signal === | === Optimizing the anomalous signal === | ||
It may be helpful to increase WFAC1 from its default 1.0 to 1.5, to avoid rejection of the strongest Bijvoet pairs (this is not necessary when STRICT_ABSORPTION_CORRECTION=TRUE which is ''not'' the default). | It may be helpful to increase WFAC1 from its default 1.0 to 1.5, to avoid rejection of the strongest Bijvoet pairs (this is not necessary when STRICT_ABSORPTION_CORRECTION=TRUE which is ''not'' the default). | ||
Read [[Tips_and_Tricks#SAD.2FMAD_data_reduction]] concerning STRICT_ABSORPTION_CORRECTION. | Read [[Tips_and_Tricks#SAD.2FMAD_data_reduction]] concerning STRICT_ABSORPTION_CORRECTION. | ||