[cctbxbb] correlation function for cctbx.miller.array

[Gabor Bunkoczi]

On 2013-10-22 18:25, Pavel Afonine wrote:
> Hi Gabor,
> 
> I coded "map_correlation" method in
> cctbx_project/cctbx/miller/__init__.py based on (if I recall it
> correctly):
> 
> Acta Cryst. (1993). D49, 530-533
> Mean phase error and the map-correlation coefficient
> Lunin and Woolfson
> 
> I'm not aware of functionality you described...
> 
> I guess you can create a clone of "map_correlation" with modifications
> you want, and add a corresponding method with some (long)
> self-explicable name and a regression test along with it.

Thanks for confirming this. I go ahead and add it, since this is a 
generic operation between two functions. I will possibly call it 
"cross_correlation_map".

http://en.wikipedia.org/wiki/Cross_correlation

BW, Gabor


> 
> Pavel
> 
> 
> On 10/22/13 10:01 AM, Gabor Bunkoczi wrote:
>> Hi,
>> 
>> I need to calculate the correlation function between two maps, both of
>> them are stored as miller.array objects. There is a map_correlation
>> method, which does something similar to what I want, but this 
>> calculates
>> the total correlation coefficient, while what I need is another
>> miller.array with amplitudes = f1*f2 and phases = p2-p1 (where f1, f2
>> are amplitudes and p1, p2 are phases of map1 and map2, respectively),
>> i.e. not just the sum of these. Is this available somewhere?
>> 
>> There is the additional complication that the hkl-list for map1 and 
>> map2
>> may not be fully identical, but the intersect of the two maps could be
>> taken.
>> 
>> Thanks, Gabor
>> 
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      Dr Gabor Bunkoczi

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