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Re: Transfer from msCIF: refine_ls_class category

  • To: Multiple recipients of list <coredmg@iucr.org>
  • Subject: Re: Transfer from msCIF: refine_ls_class category
  • From: Howard Flack <Howard.Flack@cryst.unige.ch>
  • Date: Mon, 14 Sep 1998 09:53:03 +0100 (BST)
I am sure that the idea of incorporating the notion of reflection
classes proposed for the mscif dictionary into the core dictionary
should be carried out. 
  I thank Brian for his work into trying to put this into effect and the
comments that result therefrom. 

  I have given some thought to the matter and tried to simplify and make
the best of the proposal. The result is shown in the following table
followed by my comments. I note from David's e-mail that he was going
down the same road.

####################################
## EXISTING CATEGORY DIFFRN_REFLN ##
####################################
   _diffrn_refln_class_code ---->-------->--------
#########################                         |
## DIFFRN_REFLNS_CLASS ##                         |
#########################                         |
   _diffrn_reflns_class_[]                        |
 * _diffrn_reflns_class_code <--<--------<--------            
   _diffrn_reflns_class_description
   _diffrn_reflns_class_number_of_reflns_measured_all
   _diffrn_reflns_class_number_of_reflns_measured_gt
   _diffrn_reflns_class_number_of_reflns_unique_all
   _diffrn_reflns_class_number_of_reflns_unique_gt
   _diffrn_reflns_class_number_of_reflns_unique_possible
   _diffrn_reflns_class_percent_of_reflns_possible_all
   _diffrn_reflns_class_percent_of_reflns_possible_gt
   _diffrn_reflns_class_d_res_high                   
   _diffrn_reflns_class_d_res_low                    
   _diffrn_reflns_class_av_R_eq               
   _diffrn_reflns_class_av_sgI/I                          
   _diffrn_reflns_class_meanI_over_sigI_all
   _diffrn_reflns_class_meanI_over_sigI_gt
   _diffrn_reflns_class_Rmerge_F_all
   _diffrn_reflns_class_Rmerge_F_gt
   _diffrn_reflns_class_Rmerge_I_all
   _diffrn_reflns_class_Rmerge_I_gt                  

#############################                          
## EXISTING CATEGORY REFLN ##                          
#############################                          
   _refln_class_code
--->------->------->---------                           
##################                               
|                           
## REFLNS_CLASS ##                               
|                           
##################                               
|                           
   _reflns_class_[]                              
|                       
 * _reflns_class_code <---------<--------<------- 
   _reflns_class_description
   _reflns_class_number_of_reflns_total       
   _reflns_class_number_of_reflns_gt         
   _reflns_class_d_res_high                     
   _reflns_class_d_res_low                      
   _reflns_class_R_factor_all                   
   _reflns_class_R_factor_gt                     
   _reflns_class_R_Fsqd_factor                   
   _reflns_class_R_I_factor                      
   _reflns_class_wR_factor_all                    


Comments:

 (1) One may well wish to class (or bin) raw diffraction data and
reduced diffraction data according to different criteria. For the first,
experimental factors such as  setting angle, time,  film or plate
number, run number may be required. For the second, parity group, index
group (for satellites), or random (for R free) are more obvious choices.
For this reason, I separate completely the structure of the binning of
_diffrn_reflns and _reflns.

 (2) One may well wish to bin reflections simultaneously according to
several criteria. If a criterion for binning is very simple, (e.g.
resolution shell, parity or index group) it is not worth the bother of
using the parent/child code which links the individual reflection to the
class. _code is thus optional. On the other hand, the _code is very
useful in cases where the criteria for the bins is more complicated
(e.g. the reflections chosen for an R free calculation.). How many
_codes are really necessary? I have put in just one.

 (3) I have attempted to make the data names as uniform as possible but
I did not check to see if they concord with the style of existing data
names in the core dictionary.  I have not attempted to work over the
individual definitions as 
  (a) I have changed some of the names and 
  (b) I have changed the category of some of the data items.
The only name I have removed is the "number of classes" for which I see
no great purpose but do not feel strongly about it. If included, it
should be there for _diffrn_reflns and _reflns.

H.
-- 
Howard Flack        http://www.unige.ch/crystal/ahdf/Howard.Flack.html
Laboratoire de Cristallographie               Phone: 41 (22) 702 62 49
24 quai Ernest-Ansermet             mailto:Howard.Flack@cryst.unige.ch
CH-1211 Geneva 4, Switzerland                   Fax: 41 (22) 781 21 92

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