[ccp4bb]: Reducing the size of a FreeR-set

[Wulf Blankenfeldt <wb6@st-andrews.ac.uk>]

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Dear all,

I'm trying to reduce the FreeR-set of one of my files from 10 % to 5 %.

To be politically correct and keep half of this original set for further 
refinement my first idea was to generate a second FreeR-column with 
'uniqueify -p 0.5'. I thought that this should select half of my original 
FreeR-reflections as double-flagged. A few conversion, grep and awk steps 
should give me the desired new FreeR-set, I thought.

While I now have a script that is technically doing the steps described 
above my initial assumption of getting half of the reflections 
double-flagged turned out to be wrong. Of the original say 15000 FreeR 
data, approx. 14300 got the double flag (0.00       0.00) and only 700 
don't (0.00       1.00). I am obviously missing something 
distribution-related here I think.

Does anybody know how to split a FreeR set? Is there a standard procedure 
in CCP4 that I have overlooked?



Thanks in advance,




Wulf


-----------------
Dr. Wulf Blankenfeldt

Structural Biology Group
Biomolecular Sciences Building
University of St. Andrews

North Haugh
St. Andrews, Fife
KY16 9ST
UK

Tel:    +44 (0) 13 34 - 46 72 82
Fax:    +44 (0) 13 34 - 46 25 95
e-mail: wb6@st-andrews.ac.uk
-----------------