phenix.auto_sharpen expected filtration of input map
Hi, So far I have liked very much the results of phenix.auto_sharpen, but one thing is not yet clear to me: how does it expect the input map to be filtered? Would be something like: a) Unsharpened, unfiltered map (e.g. the simple average of the half-maps) b) Unsharpened, SSNR-weighted (Cref) (Rosenthal & Henderson, JMB 2003) c) Doesn't matter / other? Thanks in advance! Best wishes, -- Ricardo Diogo Righetto
Hi Ricardo,
If you are using phenix.auto_sharpen with just a map and resolution as
inputs, then it will (by default) apply an overall sharpening B-factor up
to the resolution limit you supply, and then a blurring B-factor beyond
that. This means that any filtering applied to the input map will make a
difference. I haven't tested systematically, but my guess is that the
better the map you start with with the better the map you'll get. So I
would recommend starting with the weighted map as in Rosenthal and
Henderson. In this case phenix.auto_sharpen will basically be identifying
the overall sharpening that optimizes the clarity and connectivity of the
map.
If you sharpen using a model, then a different sharpening is applied at
each resolution (basically as in Rosenthal and Henderson, but based on the
match between model and map, not between two half-maps), so the starting
map should make only a small difference.
All the best,
Tom T
On Wed, Jan 24, 2018 at 6:00 AM, Ricardo Righetto
wrote:
-- Thomas C Terwilliger Laboratory Fellow, Los Alamos National Laboratory Senior Scientist, New Mexico Consortium 100 Entrada Dr, Los Alamos, NM 87544 Email: tterwilliger@newmexicoconsortium.org Tel: 505-431-0033
participants (2)
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Ricardo Righetto -
Tom Terwilliger