REFERENCE DATA SET

Sometimes one wants to use a REFERENCE_DATA_SET which was not itself written out by XDS or XSCALE.

For a file to be accepted as a REFERENCE_DATA_SET by XDS, it must minimally look like:

!FORMAT=XDS_ASCII
!END_OF_HEADER
   1   0   4  48445. 983.361   
   1   0   5 2124.59 283.825  
   1   0   6  17955. 493.356   
   1   0   7  19328. 510.718   
   1   0   8  87172. 3437.40   
...
...
!END_OF_DATA

The columns do not have a specified width, and are separated by a blank (Fortran's free format). Such a file, which I would call "fake XDS_ASCII" can be easily obtained. Additional columns besides h k l I sigI will be ignored. Anomalous data in that file will be treated as required by the setting of FRIEDEL'S_LAW in XDS.INP.

Please note that the REFERENCE_DATA_SET will only be used if SPACE_GROUP_NUMBER > 0 is specified in XDS.INP !

For use with XSCALE, the file must look like e.g.:

!FORMAT=XDS_ASCII
!NUMBER_OF_ITEMS_IN_EACH_DATA_RECORD=   5
!ITEM_H=1
!ITEM_K=2
!ITEM_L=3
!ITEM_IOBS=4
!ITEM_SIGMA(IOBS)=5
!END_OF_HEADER
   1   0   4  48445. 983.361   
   1   0   5 2124.59 283.825  
   1   0   6  17955. 493.356   
   1   0   7  19328. 510.718   
   1   0   8  87172. 3437.40   
...
...
!END_OF_DATA