Have you looked at http://www.ccp4.ac.uk/dist/html/pxmaths/index.html
It is an introduction ..
Eleanor
Randy talked about deviations at the CCP4 study weekend this year..
Winter, G (Graeme) wrote:
>
> Hi Folks,
>
> I was wondering if there is a document somewhere explaining some of
> the more interesting things which can be interpreted from the plot of
> second moment of Z = I'/<I'> anywhere? I've looked around and I can't
> find much beyond the things pertaining to twinning, where it will have
> the magical values of 2.0 or 1.5. What about if it is say 2.0 around
> the low resolution regions but gets much bigger?
>
> Looking at the truncate source code there is a note to the effect that
> the second moments may be greater than two in when you have
> pseudotranslational symmetry. In this case, however, I would expect
> that the effect would be uniform across the resolution ranges… any
> thoughts?
>
> Any pointers would be greatly appreciated.
>
> Thanks,
>
> Graeme
>
|