On 24/05/12 11:03, Ian Tickle wrote:
Hi Graeme
This has nothing to do with Randy's 1986 paper on minimally-biased map
coefficients from partial structures (which I assume is the one you're
referring to) since as you said yourself these are experimental, not
partial structure, phases. Rather, this is Blow& Crick's (1959)
result where they showed that coefficients m*F with the centroid phase
give the electron density with the least mean-square error over the
unit cell. But maybe the error in the density is not something you
need to worry about, since if the signal/noise ratio is sufficiently
high the peaks will stand out against the background anyway?
Paul's solution looks like the best one (once tested!).
Hmm... either that or read in the shelx output directly and let Coot
calculate the sigmaa map... (which is the thing I'd try first - Coot may
well be picky about the right type of Shelx* output).
Paul.
