Re: [ccp4bb]: about R-factor of twinning data

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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xinqi liu wrote:
> 
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> 
> Hi, everyone,
> 
>    My data is merohedral twinning, after I detwined
> the data by DETWIN (CCP4), I use CNS to refine it. If
> I use the regular program in CNS, I can get R-factor
> about 29% (R-free 32%), with excellent density map. If
> I use the CNS/twinning program to refine, which will
> induce into a twin fraction and twin operator, that
> will give a R-facor of 22% (R-free 25%). But the
> density map is quite similar. Does someone know the
> difference of the method of these two program to
> caculate the R-facor, and which one is right?
> 
> Thank you very much.
> 
> xinqi
> 
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 Oh dear! That sounds bad..

 You dont say what the space group is, or what he twinning fraction is,
or what the operator is ...

 Could you give us some more details?

 Eleanor