When does it write CC per atom vs per
residue? Can you please elaborate?
it's resolution dependent.
Say you are looking at ARG (or something similar with long side
chain), which has a few atoms sticking out of density, while the
other atoms are well placed into density. Then if you compute CC for
the whole residue it will still be high enough to mislead you
thinking that everything is all right with this residue. However, if
you compute CC per atom it will immediately red-flag these few atoms
that are not in density.
Computing CC per atom actually makes only sense if density shows you
atoms, that is the data resolution is high enough. For example, you
would not want to compute CC per atom at resolutions like 3A or so.
Is there a way to tell the program
to write CC one way or the other?
phenix.real_space_correlation allows more fine tuning. In particular
it allows you to specify whether to output CC per atom or per
residue.