[phenixbb] poor phasing

[Francis E Reyes]

R vs R statistic:
   R_abs_twin = <|I1-I2|>/<|I1+I2|>
   Lebedev, Vagin, Murshudov. Acta Cryst. (2006). D62, 83-95

    R_abs_twin observed data   : 0.012
    R_abs_twin calculated data : 0.300

Is R_abs_twin the same thing as Robs_twin in Lebedev, Vagin,  
Murshudov. Acta Cryst. (2006). D62, 83-95 ?

And I guess I have rotational pseudo symmetry with Rcalctwin < 1/2.

Interestingly when I run xtriage when the data is scaled into P 41 21  
2 I get the following stats
R vs R statistic:
   R_abs_twin = <|I1-I2|>/<|I1+I2|>
   Lebedev, Vagin, Murshudov. Acta Cryst. (2006). D62, 83-95

    R_abs_twin observed data   : 0.012
    R_abs_twin calculated data : 0.521

since r_abs_twin or r_obs_twin ~= 0, that's an indicator for perfect  
twinning.


FR

On Apr 27, 2009, at 8:58 AM, Peter Zwart wrote:

> Try supplying a pdb file
>
> phenix.xtriage mydata.sca reference.structure.file=mymodel.pdb
>
> for the RvsR analyses.
>
> P
>
> 2009/4/27 Francis E Reyes <Francis.Reyes at colorado.edu>:
>> Interesting. I checked my data in P4 with xtriage and yet L-test  
>> comes
>> at a respectable 0.948. How does one assess pseudo rotational  
>> symmetry
>> in the refined structure?
>>
>> Thanks
>>
>> FR
>>
>> On Apr 27, 2009, at 8:48 AM, Peter Zwart wrote:
>>
>>>> I have yet to find a twinning test that can assess perfect  
>>>> twinning.
>>>
>>> I think you mean perfect twinning in the presence of pseudo
>>> rotational symmetry.
>>> Without the latter part, The L-test works very well.
>>>
>>> P
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>>
>> ---------------------------------------------
>> Francis Reyes M.Sc.
>> 215 UCB
>> University of Colorado at Boulder
>>
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>
>
>
> -- 
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> P.H. Zwart
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> Berkeley Center for Structural Biology
> Lawrence Berkeley National Laboratories
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---------------------------------------------
Francis Reyes M.Sc.
215 UCB
University of Colorado at Boulder

gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D

8AE2 F2F4 90F7 9640 28BC  686F 78FD 6669 67BA 8D5D