[phenixbb] Grid size in max_entropy maps

Pavel Afonine pafonine at lbl.gov
Thu May 16 15:29:18 PDT 2013

Hi Carsten,

Fourier map coefficients calculated from MEM map typically extend to 
high resolutions (d_min) ~0.2-0.7A or so:

Since map gridding is d_min/4 that in turn means you get very fine 
sampling. Cutting back resolution essentially means invalidating MEM 
results. phenix.maximum_entropy_map outputs MTZ file with two sets of 
map coefficients, original and MEM, so if you load them into Coot you 
will get both maps sampled at the same grid so at least visually they 
are comparable, and therefore sampling should not be a problem.

Alternatively, I can add an option to phenix.maximum_entropy_map so it 
outputs actual MEM map (in CCP4 binary format or in X-plor format). Then 
it will have d_min/4 sampling, where d_min is the resolution on input 
data set.


On 5/16/13 11:09 AM, Schubert, Carsten [JRDUS] wrote:
> Is there a way to control the grid size in the maximum entropy maps? The current grid size is quite small, resulting in a very fine mesh.
> Thanks
> 	Carsten

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