I think you are talking about the R of the reflections in an image to the set
of unique reflections resulting from scaling.
Here is a definition of Rmerge from a dtscaleaverage log file:
In the tables below Rmerge is defined as:
Rmerge = Sum Sum |Ihi - <Ih>| / Sum Sum <Ih>
h i h i
where Ihi is the ith used observation for unique hkl h,
and <Ih> is the mean intensity for unique hkl h.
Here is a definition of Rmeas from a dtscaleaverage log file:
In the tables below the redundancy-independent merging
R factor Rmeas (or Rrim) is defined as:
Rmeas = Sum [N/(N-1)]^(1/2) Sum |Ihi - <Ih>| / Sum Sum <Ih>
h i h i
where Ihi is the ith used observation for unique hkl h,
and <Ih> is the mean intensity for unique hkl h.
Sorry, but that's what "text only" gives you.
<Ih> is calculated from the entire scaled data set and is the unique hkl. If a
batch or image does not have that unique reflection, then it would not appear
in the above equations.
Also if only 1 reflection was used to calculate <Ih>, then it is not included
in the sums. Quiz time: Can you tell me why?
Jim
________________________________________
From: CCP4 bulletin board [[email protected]] on behalf of Keller, Jacob
[[email protected]]
Sent: Wednesday, February 12, 2014 10:46 PM
To: [email protected]
Subject: [ccp4bb] Rmerge of Images
Dear Crystallographers,
Where can I find the definition of the R vs batch reported in scaling?
Specifically I am wondering whether it is cumulative (each new frame versus all
previous ones pooled together) or something else, and also how this metric can
have any meaning on early frames when one has measured each reflection only
once (in p1, this would be 180 degrees). I am wondering about its efficacy as a
radiation-damage metric.
JPK
*******************************************
Jacob Pearson Keller, PhD
Looger Lab/HHMI Janelia Farms Research Campus
19700 Helix Dr, Ashburn, VA 20147
email: [email protected]
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