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Re: [ccp4bb] differences between Rsym and Rmerge
 

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CCP4bb <-- 2008 <-- January 2008 <-- 18 January 2008
Previous message:
Subject: Re: differences between Rsym and Rmerge
From: "Manfred S {- dot -} Weiss" msweiss {- at -} EMBL-HAMBURG {- dot -} DE
Date: 2008-01-18 		Next message:
Subject: Re: Fwd: crystallisation robot
From: Lisa A Nagy lisanagy {- at -} UAB {- dot -} EDU
Date: 2008-01-18


Subject: Re: differences between Rsym and Rmerge
From: "Santarsiero, Bernard D {- dot -} " bds {- at -} UIC {- dot -} EDU
Date: 2008-01-18
I seem to recall hearing Rsym first when I used the Xuong-Hamlin detector,
since there were a substantial number of redundancies. There were two
Rsyms, one called Rrms for the sqrt over the sum of weighted squared
differences and and Rav for the linear summation of unweighted
differences. This was for protein work.

I do recall Rmerge being more popular with the small molecule
crystallographers. However, I also recall a difference between averaging
over pairs of reflections that were or were not Bijvoet pairs, for even
small differences in the anomalous scattering contributions.

Bernie



On Fri, January 18, 2008 9:29 am, R.M. Garavito wrote:
> Kay,
>
> I beg to differ, but only in a pedantic way. Historically, Rsym
> would refer to the agreement in symmetry-related reflections within a
> single data set and Rmerge would be the agreement between 2 or more
> data sets that were merged. This was the way we did it back in the
> "old day" of precession photography and early oscillation
> photography. While the terms seem synonymous today, the recent
> thread "[ccp4bb] combine incomplete data sets" illustrates where such
> a distinction is still relevant, where the "merging" is between data
> collected under different experimental conditions (i.e., a different
> crystal in a different orientation).
>
> Michael
>
> ****************************************************************
> R. Michael Garavito, Ph.D.
> Professor of Biochemistry & Molecular Biology
> 513 Biochemistry Bldg.
> Michigan State University
> East Lansing, MI 48824-1319
> Office: (517) 355-9724 Lab: (517) 353-9125
> FAX: (517) 353-9334 Email: garavito@msu.edu
> ****************************************************************
>
>
> On Jan 18, 2008, at 10:15 AM, Kay Diederichs wrote:
>
>> Salameh, Mohd A., Ph.D. schrieb:
>>> Hi everybody!
>>> I will appreciate it if anybody can clarify to me the differences
>>> between Rmerge and Rsym. Many thanks, M
>>
>> there is no difference - unfortunately there are two words for the
>> same thing. "Rmerge" currently appears to be more in fashion.
>>
>> just my 2 cents,
>>
>> Kay
>> --
>> Kay Diederichs http://strucbio.biologie.uni-konstanz.de
>> email: Kay.Diederichs@uni-konstanz.de Tel +49 7531 88 4049 Fax 3183
>> Fachbereich Biologie, Universität Konstanz, Box M647, D-78457 Konstanz
>
>

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CCP4bb <-- 2008 <-- January 2008 <-- 18 January 2008
Previous message:
Subject: Re: differences between Rsym and Rmerge
From: "Manfred S {- dot -} Weiss" msweiss {- at -} EMBL-HAMBURG {- dot -} DE
Date: 2008-01-18 		Next message:
Subject: Re: Fwd: crystallisation robot
From: Lisa A Nagy lisanagy {- at -} UAB {- dot -} EDU
Date: 2008-01-18


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