On 27 Jan 2015, at 20:25, James Holton <jmhol...@lbl.gov> wrote: … snip
> Now you can ask questions about the phase shift. The problem with phases is > that the phase of weak reflections doesn't really matter because they don't > contribute to the map. Also, poorly-measured phases get low FOM weights in > map calculations as well. For this reason, the phase shift in rms degrees is > not really all that useful. Better to consider the correlation coefficient > of the two electron density maps. In the case of 3aw6 vs 3aw7 you get CC= > 0.7. Not too bad really. Gerard Bricogne pointed out a long time ago that the clearest comparison between two sets of phases is the complex correlation coefficient between two "best" structure factors ( m F exp(i phi) ) - this is equivalent to map correlation, but can be analysed in resolution bins. I'm not sure whether there are programs which calculate this, though it's straightforward, and I've had various jiffy programs in the past (which I've probably lost) Phil
