Re: [ccp4bb] meaning of R free of perfect twin

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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From: Felix Frolow mbfrolow {- at -} POST {- dot -} TAU {- dot -} AC {- dot -} IL
Date: 2008-12-11

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Subject: Re: meaning of R free of perfect twin
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2008-12-11

you need to select the Free R in the highest possible Laue group , then
use cad to extend this to all reflections in the chosen point group.
This is best done immediately post-truncate..

eg if you twinning operator is k,h,-l, then if
1,2, 3 is assigned to the free set so should 2, 1, -3 be.

PHENIX.xtriage does it properly

REFMAC does not use it properly I dont think, but maybe that has been
fixed..

Eleanor

Serge Cohen wrote:
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> I guess the independence is mostly depending on how you select the
> reflection that lie in the free-set.
>
> If (from the beginning) you select reflections that are related by the
> twin operator to be both in the free-set you keep the "independence"
> of the free-set.
>
> Serge.
>
> Le 5 déc. 08 à 13:50, Agnieszka Kiliszek a écrit :
>
>> Hi,
>>
>> What is the meaning of R free of perfect twin? Shelxl counts it but it
>> seems that the R f is no longer independent.
>>
>> Aga
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CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: License
From: Felix Frolow mbfrolow {- at -} POST {- dot -} TAU {- dot -} AC {- dot -} IL
Date: 2008-12-11

Next message:
Subject: Re: Summary - torsion angle restraints in REFMAC
From: Artem Evdokimov artem {- at -} XTALS {- dot -} ORG
Date: 2008-12-11