Hi Ian,
... or you could just use the RMSD of the difference map (i.e. that
using 2(mFo-DFc) coefficients for acentric reflns), which is a
reasonable approximation of the uncertainty provided most of the
structure is accounted for, as the uncertainty of the Fourier map
(i.e. that using 2mFo-DFc for acentrics). Note that for this to work
you must use the correct 'minimally biased' coefficients, i.e.
2(mFo-DFc) for acentric reflns, and (mFo-DFc) for centrics; I suspect
some programs are still not doing this correctly.
thanks for shedding some light on this subject! I coded this way of map
calculation in phenix.refine without actually understanding why it has
to be this way. Did anybody discuss this in the literature (or it's too
obvious to be worth of discussion -:) )?
Pavel.
